From 344e2ac7d14241ed49f747ddd318aedefb731d5d Mon Sep 17 00:00:00 2001
From: viettranx <viettranx@gmail.com>
Date: Mon, 9 Mar 2026 22:22:42 +0700
Subject: [PATCH] feat(i18n): add full i18n support for backend and web UI

- Add i18next + react-i18next with namespace-split locale files (27 namespaces x 3 languages)
- Add language switcher in topbar (EN/VI/ZH) with localStorage persistence
- Replace hardcoded strings in 160+ React components with t() translations
- Add Go message catalog (internal/i18n) with T(locale, key, args...) function
- Replace 81 hardcoded error strings in gateway methods and HTTP handlers
- Add locale context propagation: WS connect param + HTTP Accept-Language header
- Keep technical terms in English: Agent, Session, Channel, Provider, Skill, Team, MCP, Cron
- Update CLAUDE.md and review-pr skill with i18n compliance checks
---
 CLAUDE.md                                     |   5 +-
 internal/gateway/client.go                    |   2 +
 internal/gateway/methods/agent_links.go       |  64 ++--
 internal/gateway/methods/agents.go            |   6 +-
 internal/gateway/methods/agents_create.go     |  16 +-
 internal/gateway/methods/agents_delete.go     |  17 +-
 internal/gateway/methods/agents_files.go      |  32 +-
 internal/gateway/methods/agents_update.go     |  15 +-
 internal/gateway/methods/channel_instances.go |  34 +-
 internal/gateway/methods/channels.go          |   7 +-
 internal/gateway/methods/chat.go              |  27 +-
 internal/gateway/methods/config.go            |  23 +-
 internal/gateway/methods/cron.go              |  48 +--
 internal/gateway/methods/delegations.go       |  17 +-
 internal/gateway/methods/exec_approval.go     |  20 +-
 internal/gateway/methods/logs.go              |   7 +-
 internal/gateway/methods/pairing.go           |  24 +-
 internal/gateway/methods/send.go              |  11 +-
 internal/gateway/methods/sessions.go          |  23 +-
 internal/gateway/methods/skills.go            |  23 +-
 internal/gateway/methods/teams.go             |  24 +-
 internal/gateway/methods/teams_crud.go        |  71 ++--
 internal/gateway/methods/teams_members.go     |  41 +--
 internal/gateway/router.go                    |  15 +-
 internal/http/agents.go                       |  50 +--
 internal/http/agents_instances.go             |  47 +--
 internal/http/agents_sharing.go               |  54 +--
 internal/http/auth.go                         |  19 +
 internal/http/builtin_tools.go                |  19 +-
 internal/http/channel_instances.go            |  87 +++--
 internal/http/chat_completions.go             |  29 +-
 internal/http/custom_tools.go                 |  38 +-
 internal/http/delegations.go                  |  10 +-
 internal/http/files.go                        |  10 +-
 internal/http/knowledge_graph_handlers.go     |  23 +-
 internal/http/mcp.go                          |  35 +-
 internal/http/mcp_grants.go                   |  31 +-
 internal/http/mcp_requests.go                 |  13 +-
 internal/http/mcp_tools.go                    |  12 +-
 internal/http/media_serve.go                  |   7 +-
 internal/http/media_upload.go                 |  15 +-
 internal/http/memory.go                       |   4 +-
 internal/http/memory_handlers.go              |  20 +-
 internal/http/oauth.go                        |  14 +-
 internal/http/pending_messages.go             |  18 +-
 internal/http/provider_models.go              |   8 +-
 internal/http/provider_verify.go              |  10 +-
 internal/http/providers.go                    |  35 +-
 internal/http/skills.go                       |  21 +-
 internal/http/skills_grants.go                |  28 +-
 internal/http/skills_upload.go                |  24 +-
 internal/http/skills_versions.go              |  38 +-
 internal/http/storage.go                      |  40 +-
 internal/http/tools_invoke.go                 |  14 +-
 internal/http/traces.go                       |  12 +-
 internal/i18n/catalog_en.go                   | 132 +++++++
 internal/i18n/catalog_vi.go                   | 132 +++++++
 internal/i18n/catalog_zh.go                   | 132 +++++++
 internal/i18n/i18n.go                         |  80 ++++
 internal/i18n/keys.go                         | 132 +++++++
 internal/store/context.go                     |  15 +
 ui/web/package.json                           |   2 +
 ui/web/pnpm-lock.yaml                         |  66 ++++
 ui/web/src/api/ws-client.ts                   |   1 +
 ui/web/src/components/chat/agent-selector.tsx |   8 +-
 ui/web/src/components/chat/chat-input.tsx     |   8 +-
 ui/web/src/components/chat/rich-content.tsx   |  21 +-
 .../src/components/chat/session-switcher.tsx  |   6 +-
 ui/web/src/components/chat/thinking-block.tsx |   4 +-
 ui/web/src/components/chat/tool-call-card.tsx |  11 +-
 ui/web/src/components/layout/app-layout.tsx   |   4 +-
 .../components/layout/connection-status.tsx   |   4 +-
 ui/web/src/components/layout/sidebar.tsx      |  58 +--
 ui/web/src/components/layout/topbar.tsx       |  31 +-
 .../shared/confirm-delete-dialog.tsx          |  10 +-
 .../src/components/shared/confirm-dialog.tsx  |   8 +-
 ui/web/src/components/shared/file-browser.tsx |   4 +-
 ui/web/src/components/shared/file-tree.tsx    |   4 +-
 ui/web/src/components/shared/file-viewers.tsx |   4 +-
 ui/web/src/components/shared/pagination.tsx   |   8 +-
 .../shared/provider-model-select.tsx          |  28 +-
 ui/web/src/components/shared/search-input.tsx |   6 +-
 ui/web/src/components/shared/tag-input.tsx    |   6 +-
 .../components/shared/tool-name-select.tsx    |  10 +-
 ui/web/src/i18n/index.ts                      | 161 +++++++++
 ui/web/src/i18n/locales/en/agents.json        | 342 ++++++++++++++++++
 ui/web/src/i18n/locales/en/approvals.json     |  23 ++
 ui/web/src/i18n/locales/en/channels.json      | 213 +++++++++++
 ui/web/src/i18n/locales/en/chat.json          |  20 +
 ui/web/src/i18n/locales/en/common.json        | 104 ++++++
 ui/web/src/i18n/locales/en/cron.json          | 102 ++++++
 ui/web/src/i18n/locales/en/delegations.json   |  41 +++
 ui/web/src/i18n/locales/en/events.json        |  34 ++
 ui/web/src/i18n/locales/en/login.json         |  32 ++
 ui/web/src/i18n/locales/en/logs.json          |  15 +
 ui/web/src/i18n/locales/en/mcp.json           |  99 +++++
 ui/web/src/i18n/locales/en/memory.json        | 166 +++++++++
 ui/web/src/i18n/locales/en/nodes.json         |  35 ++
 ui/web/src/i18n/locales/en/overview.json      |  74 ++++
 .../src/i18n/locales/en/pending-messages.json |  31 ++
 ui/web/src/i18n/locales/en/providers.json     | 115 ++++++
 ui/web/src/i18n/locales/en/sessions.json      |  34 ++
 ui/web/src/i18n/locales/en/setup.json         | 102 ++++++
 ui/web/src/i18n/locales/en/sidebar.json       |  34 ++
 ui/web/src/i18n/locales/en/skills.json        |  55 +++
 ui/web/src/i18n/locales/en/storage.json       |  14 +
 ui/web/src/i18n/locales/en/teams.json         | 150 ++++++++
 ui/web/src/i18n/locales/en/tools.json         | 156 ++++++++
 ui/web/src/i18n/locales/en/topbar.json        |  16 +
 ui/web/src/i18n/locales/en/traces.json        |  49 +++
 ui/web/src/i18n/locales/en/tts.json           |  71 ++++
 ui/web/src/i18n/locales/en/usage.json         |  21 ++
 ui/web/src/i18n/locales/vi/agents.json        | 342 ++++++++++++++++++
 ui/web/src/i18n/locales/vi/approvals.json     |  23 ++
 ui/web/src/i18n/locales/vi/channels.json      | 213 +++++++++++
 ui/web/src/i18n/locales/vi/chat.json          |  20 +
 ui/web/src/i18n/locales/vi/common.json        | 104 ++++++
 ui/web/src/i18n/locales/vi/cron.json          | 102 ++++++
 ui/web/src/i18n/locales/vi/delegations.json   |  41 +++
 ui/web/src/i18n/locales/vi/events.json        |  34 ++
 ui/web/src/i18n/locales/vi/login.json         |  32 ++
 ui/web/src/i18n/locales/vi/logs.json          |  15 +
 ui/web/src/i18n/locales/vi/mcp.json           |  99 +++++
 ui/web/src/i18n/locales/vi/memory.json        | 166 +++++++++
 ui/web/src/i18n/locales/vi/nodes.json         |  35 ++
 ui/web/src/i18n/locales/vi/overview.json      |  74 ++++
 .../src/i18n/locales/vi/pending-messages.json |  31 ++
 ui/web/src/i18n/locales/vi/providers.json     | 115 ++++++
 ui/web/src/i18n/locales/vi/sessions.json      |  34 ++
 ui/web/src/i18n/locales/vi/setup.json         | 102 ++++++
 ui/web/src/i18n/locales/vi/sidebar.json       |  34 ++
 ui/web/src/i18n/locales/vi/skills.json        |  55 +++
 ui/web/src/i18n/locales/vi/storage.json       |  14 +
 ui/web/src/i18n/locales/vi/teams.json         | 150 ++++++++
 ui/web/src/i18n/locales/vi/tools.json         | 156 ++++++++
 ui/web/src/i18n/locales/vi/topbar.json        |  16 +
 ui/web/src/i18n/locales/vi/traces.json        |  49 +++
 ui/web/src/i18n/locales/vi/tts.json           |  71 ++++
 ui/web/src/i18n/locales/vi/usage.json         |  21 ++
 ui/web/src/i18n/locales/zh/agents.json        | 342 ++++++++++++++++++
 ui/web/src/i18n/locales/zh/approvals.json     |  23 ++
 ui/web/src/i18n/locales/zh/channels.json      | 213 +++++++++++
 ui/web/src/i18n/locales/zh/chat.json          |  20 +
 ui/web/src/i18n/locales/zh/common.json        | 104 ++++++
 ui/web/src/i18n/locales/zh/cron.json          | 102 ++++++
 ui/web/src/i18n/locales/zh/delegations.json   |  41 +++
 ui/web/src/i18n/locales/zh/events.json        |  34 ++
 ui/web/src/i18n/locales/zh/login.json         |  32 ++
 ui/web/src/i18n/locales/zh/logs.json          |  15 +
 ui/web/src/i18n/locales/zh/mcp.json           |  99 +++++
 ui/web/src/i18n/locales/zh/memory.json        | 166 +++++++++
 ui/web/src/i18n/locales/zh/nodes.json         |  35 ++
 ui/web/src/i18n/locales/zh/overview.json      |  74 ++++
 .../src/i18n/locales/zh/pending-messages.json |  31 ++
 ui/web/src/i18n/locales/zh/providers.json     | 115 ++++++
 ui/web/src/i18n/locales/zh/sessions.json      |  34 ++
 ui/web/src/i18n/locales/zh/setup.json         | 102 ++++++
 ui/web/src/i18n/locales/zh/sidebar.json       |  34 ++
 ui/web/src/i18n/locales/zh/skills.json        |  55 +++
 ui/web/src/i18n/locales/zh/storage.json       |  14 +
 ui/web/src/i18n/locales/zh/teams.json         | 150 ++++++++
 ui/web/src/i18n/locales/zh/tools.json         | 156 ++++++++
 ui/web/src/i18n/locales/zh/topbar.json        |  16 +
 ui/web/src/i18n/locales/zh/traces.json        |  49 +++
 ui/web/src/i18n/locales/zh/tts.json           |  71 ++++
 ui/web/src/i18n/locales/zh/usage.json         |  21 ++
 ui/web/src/lib/constants.ts                   |  10 +
 ui/web/src/main.tsx                           |   1 +
 ui/web/src/pages/agents/agent-card.tsx        |  22 +-
 .../src/pages/agents/agent-create-dialog.tsx  |  59 +--
 .../agents/agent-detail/agent-config-tab.tsx  |  11 +-
 .../agents/agent-detail/agent-danger-tab.tsx  |  17 +-
 .../agents/agent-detail/agent-detail-page.tsx |  43 ++-
 .../agents/agent-detail/agent-files-tab.tsx   |  23 +-
 .../agents/agent-detail/agent-general-tab.tsx |  18 +-
 .../agent-detail/agent-instances-tab.tsx      |  23 +-
 .../agents/agent-detail/agent-links-tab.tsx   |  15 +-
 .../agents/agent-detail/agent-shares-tab.tsx  |  28 +-
 .../agents/agent-detail/agent-skills-tab.tsx  |  20 +-
 .../config-sections/compaction-section.tsx    |  19 +-
 .../config-sections/config-section.tsx        |   4 +-
 .../context-pruning-section.tsx               |  31 +-
 .../config-sections/memory-section.tsx        |  21 +-
 .../config-sections/other-config-section.tsx  |  11 +-
 .../config-sections/quality-gates-section.tsx |  26 +-
 .../config-sections/sandbox-section.tsx       |  23 +-
 .../config-sections/subagents-section.tsx     |  25 +-
 .../config-sections/thinking-section.tsx      |  26 +-
 .../config-sections/tool-policy-section.tsx   |  21 +-
 .../file-sections/file-editor.tsx             |   9 +-
 .../file-sections/file-sidebar.tsx            |  10 +-
 .../file-sections/open-agent-empty-state.tsx  |  22 +-
 .../file-sections/regenerate-dialog.tsx       |  13 +-
 .../general-sections/identity-section.tsx     |  30 +-
 .../general-sections/llm-config-section.tsx   |  12 +-
 .../general-sections/workspace-section.tsx    |  15 +-
 .../link-sections/link-create-form.tsx        |  32 +-
 .../link-sections/link-edit-dialog.tsx        |  26 +-
 .../agent-detail/link-sections/link-list.tsx  |  17 +-
 ui/web/src/pages/agents/agents-page.tsx       |  22 +-
 ui/web/src/pages/agents/summoning-modal.tsx   |  26 +-
 ui/web/src/pages/approvals/approvals-page.tsx |  35 +-
 .../builtin-tool-settings-dialog.tsx          |  18 +-
 .../builtin-tools/builtin-tools-page.tsx      |  53 ++-
 .../pages/builtin-tools/kg-settings-form.tsx  |  26 +-
 .../media-provider-chain-form.tsx             |  31 +-
 .../channel-detail/channel-config-tab.tsx     |   8 +-
 .../channel-credentials-tab.tsx               |  14 +-
 .../channel-detail/channel-detail-page.tsx    |  18 +-
 .../channel-detail/channel-general-tab.tsx    |  22 +-
 .../channel-detail/channel-groups-tab.tsx     |   6 +-
 .../channel-detail/channel-writers-tab.tsx    |  66 ++--
 ui/web/src/pages/channels/channel-fields.tsx  |   6 +-
 .../channels/channel-instance-form-dialog.tsx |  69 ++--
 ui/web/src/pages/channels/channels-page.tsx   |  40 +-
 .../pages/channels/channels-status-view.tsx   |  18 +-
 .../channels/hooks/use-channel-instances.ts   |  16 +-
 .../pages/channels/telegram-group-fields.tsx  |  53 +--
 .../channels/telegram-group-overrides.tsx     |  16 +-
 .../channels/telegram-topic-overrides.tsx     |  10 +-
 .../channels/zalo/zalo-contacts-picker.tsx    |  26 +-
 .../channels/zalo/zalo-personal-qr-dialog.tsx |  14 +-
 .../pages/channels/zalo/zalo-wizard-steps.tsx |  12 +-
 ui/web/src/pages/chat/chat-page.tsx           |   6 +-
 ui/web/src/pages/chat/chat-sidebar.tsx        |   4 +-
 ui/web/src/pages/chat/chat-thread.tsx         |   6 +-
 ui/web/src/pages/config/config-page.tsx       |  36 +-
 .../sections/agents-defaults-section.tsx      |  90 ++---
 .../config/sections/bindings-section.tsx      |  20 +-
 .../config/sections/channels-section.tsx      |  34 +-
 .../pages/config/sections/cron-section.tsx    |  14 +-
 .../pages/config/sections/gateway-section.tsx |  34 +-
 .../config/sections/providers-section.tsx     |  18 +-
 .../pages/config/sections/quota-section.tsx   |  59 +--
 .../config/sections/sessions-section.tsx      |  12 +-
 .../config/sections/telemetry-section.tsx     |  26 +-
 .../pages/config/sections/tools-section.tsx   |  56 +--
 .../src/pages/config/sections/tts-section.tsx |  13 +-
 ui/web/src/pages/cron/cron-detail-page.tsx    |  60 +--
 ui/web/src/pages/cron/cron-form-dialog.tsx    |  34 +-
 ui/web/src/pages/cron/cron-page.tsx           |  51 +--
 ui/web/src/pages/cron/cron-run-log-dialog.tsx |   7 +-
 ui/web/src/pages/cron/hooks/use-cron.ts       |  17 +-
 .../custom-tools/custom-tool-form-dialog.tsx  |  44 +--
 .../pages/custom-tools/custom-tools-page.tsx  |  43 ++-
 .../custom-tools/hooks/use-custom-tools.ts    |  13 +-
 .../delegations/delegation-detail-dialog.tsx  |  30 +-
 .../pages/delegations/delegations-page.tsx    |  43 ++-
 .../event-sections/event-detail-dialog.tsx    |   4 +-
 ui/web/src/pages/events/events-page.tsx       |  62 ++--
 ui/web/src/pages/login/login-page.tsx         |   4 +-
 ui/web/src/pages/login/login-tabs.tsx         |   7 +-
 ui/web/src/pages/login/pairing-form.tsx       |  26 +-
 ui/web/src/pages/login/token-form.tsx         |  18 +-
 ui/web/src/pages/logs/logs-page.tsx           |  28 +-
 ui/web/src/pages/mcp/hooks/use-mcp.ts         |  13 +-
 ui/web/src/pages/mcp/mcp-form-dialog.tsx      |  78 ++--
 ui/web/src/pages/mcp/mcp-grants-dialog.tsx    |  32 +-
 ui/web/src/pages/mcp/mcp-page.tsx             |  41 ++-
 ui/web/src/pages/mcp/mcp-tools-dialog.tsx     |  18 +-
 ui/web/src/pages/memory/kg-entities-tab.tsx   |  36 +-
 .../pages/memory/kg-entity-detail-dialog.tsx  |  48 ++-
 ui/web/src/pages/memory/kg-extract-dialog.tsx |  16 +-
 ui/web/src/pages/memory/kg-graph-view.tsx     |   4 +-
 .../src/pages/memory/memory-create-dialog.tsx |  43 ++-
 .../pages/memory/memory-document-dialog.tsx   |  38 +-
 ui/web/src/pages/memory/memory-page.tsx       |  51 +--
 .../src/pages/memory/memory-search-dialog.tsx |  14 +-
 ui/web/src/pages/nodes/nodes-page.tsx         |  54 +--
 .../pages/overview/connected-clients-card.tsx |  16 +-
 ui/web/src/pages/overview/cron-jobs-card.tsx  |  10 +-
 ui/web/src/pages/overview/overview-page.tsx   |  34 +-
 .../src/pages/overview/quota-usage-card.tsx   |  17 +-
 .../pages/overview/recent-requests-card.tsx   |  22 +-
 .../src/pages/overview/system-health-card.tsx |  24 +-
 .../pending-messages/message-list-dialog.tsx  |   8 +-
 .../pending-messages-page.tsx                 |  45 +--
 .../pages/providers/hooks/use-providers.ts    |  16 +-
 .../pages/providers/provider-cli-section.tsx  |  20 +-
 .../pages/providers/provider-form-dialog.tsx  |  72 ++--
 .../providers/provider-oauth-section.tsx      |  46 ++-
 ui/web/src/pages/providers/providers-page.tsx |  41 ++-
 .../pages/sessions/session-detail-page.tsx    |  32 +-
 ui/web/src/pages/sessions/sessions-page.tsx   |  24 +-
 .../src/pages/setup/setup-complete-modal.tsx  |  10 +-
 ui/web/src/pages/setup/setup-layout.tsx       |   5 +-
 ui/web/src/pages/setup/setup-stepper.tsx      |  17 +-
 ui/web/src/pages/setup/step-agent.tsx         |  40 +-
 ui/web/src/pages/setup/step-channel.tsx       |  40 +-
 ui/web/src/pages/setup/step-model.tsx         |  26 +-
 ui/web/src/pages/setup/step-provider.tsx      |  30 +-
 .../src/pages/skills/skill-detail-dialog.tsx  |  12 +-
 ui/web/src/pages/skills/skill-edit-dialog.tsx |  34 +-
 .../src/pages/skills/skill-upload-dialog.tsx  |  16 +-
 ui/web/src/pages/skills/skills-page.tsx       |  34 +-
 ui/web/src/pages/storage/storage-page.tsx     |  20 +-
 .../teams/member-sections/member-list.tsx     |  13 +-
 .../task-sections/task-detail-dialog.tsx      |  23 +-
 .../pages/teams/task-sections/task-list.tsx   |  16 +-
 ui/web/src/pages/teams/team-card.tsx          |   4 +-
 ui/web/src/pages/teams/team-create-dialog.tsx |  30 +-
 .../src/pages/teams/team-delegations-tab.tsx  |  18 +-
 ui/web/src/pages/teams/team-detail-page.tsx   |  24 +-
 ui/web/src/pages/teams/team-members-tab.tsx   |  12 +-
 ui/web/src/pages/teams/team-settings-tab.tsx  |  46 +--
 ui/web/src/pages/teams/team-tasks-tab.tsx     |   4 +-
 ui/web/src/pages/teams/teams-page.tsx         |  25 +-
 .../src/pages/traces/trace-detail-dialog.tsx  |  59 +--
 ui/web/src/pages/traces/traces-page.tsx       |  33 +-
 ui/web/src/pages/tts/tts-page.tsx             | 129 +++----
 ui/web/src/pages/usage/usage-page.tsx         |  34 +-
 ui/web/src/stores/use-ui-store.ts             |  11 +-
 312 files changed, 10361 insertions(+), 2441 deletions(-)
 create mode 100644 internal/i18n/catalog_en.go
 create mode 100644 internal/i18n/catalog_vi.go
 create mode 100644 internal/i18n/catalog_zh.go
 create mode 100644 internal/i18n/i18n.go
 create mode 100644 internal/i18n/keys.go
 create mode 100644 ui/web/src/i18n/index.ts
 create mode 100644 ui/web/src/i18n/locales/en/agents.json
 create mode 100644 ui/web/src/i18n/locales/en/approvals.json
 create mode 100644 ui/web/src/i18n/locales/en/channels.json
 create mode 100644 ui/web/src/i18n/locales/en/chat.json
 create mode 100644 ui/web/src/i18n/locales/en/common.json
 create mode 100644 ui/web/src/i18n/locales/en/cron.json
 create mode 100644 ui/web/src/i18n/locales/en/delegations.json
 create mode 100644 ui/web/src/i18n/locales/en/events.json
 create mode 100644 ui/web/src/i18n/locales/en/login.json
 create mode 100644 ui/web/src/i18n/locales/en/logs.json
 create mode 100644 ui/web/src/i18n/locales/en/mcp.json
 create mode 100644 ui/web/src/i18n/locales/en/memory.json
 create mode 100644 ui/web/src/i18n/locales/en/nodes.json
 create mode 100644 ui/web/src/i18n/locales/en/overview.json
 create mode 100644 ui/web/src/i18n/locales/en/pending-messages.json
 create mode 100644 ui/web/src/i18n/locales/en/providers.json
 create mode 100644 ui/web/src/i18n/locales/en/sessions.json
 create mode 100644 ui/web/src/i18n/locales/en/setup.json
 create mode 100644 ui/web/src/i18n/locales/en/sidebar.json
 create mode 100644 ui/web/src/i18n/locales/en/skills.json
 create mode 100644 ui/web/src/i18n/locales/en/storage.json
 create mode 100644 ui/web/src/i18n/locales/en/teams.json
 create mode 100644 ui/web/src/i18n/locales/en/tools.json
 create mode 100644 ui/web/src/i18n/locales/en/topbar.json
 create mode 100644 ui/web/src/i18n/locales/en/traces.json
 create mode 100644 ui/web/src/i18n/locales/en/tts.json
 create mode 100644 ui/web/src/i18n/locales/en/usage.json
 create mode 100644 ui/web/src/i18n/locales/vi/agents.json
 create mode 100644 ui/web/src/i18n/locales/vi/approvals.json
 create mode 100644 ui/web/src/i18n/locales/vi/channels.json
 create mode 100644 ui/web/src/i18n/locales/vi/chat.json
 create mode 100644 ui/web/src/i18n/locales/vi/common.json
 create mode 100644 ui/web/src/i18n/locales/vi/cron.json
 create mode 100644 ui/web/src/i18n/locales/vi/delegations.json
 create mode 100644 ui/web/src/i18n/locales/vi/events.json
 create mode 100644 ui/web/src/i18n/locales/vi/login.json
 create mode 100644 ui/web/src/i18n/locales/vi/logs.json
 create mode 100644 ui/web/src/i18n/locales/vi/mcp.json
 create mode 100644 ui/web/src/i18n/locales/vi/memory.json
 create mode 100644 ui/web/src/i18n/locales/vi/nodes.json
 create mode 100644 ui/web/src/i18n/locales/vi/overview.json
 create mode 100644 ui/web/src/i18n/locales/vi/pending-messages.json
 create mode 100644 ui/web/src/i18n/locales/vi/providers.json
 create mode 100644 ui/web/src/i18n/locales/vi/sessions.json
 create mode 100644 ui/web/src/i18n/locales/vi/setup.json
 create mode 100644 ui/web/src/i18n/locales/vi/sidebar.json
 create mode 100644 ui/web/src/i18n/locales/vi/skills.json
 create mode 100644 ui/web/src/i18n/locales/vi/storage.json
 create mode 100644 ui/web/src/i18n/locales/vi/teams.json
 create mode 100644 ui/web/src/i18n/locales/vi/tools.json
 create mode 100644 ui/web/src/i18n/locales/vi/topbar.json
 create mode 100644 ui/web/src/i18n/locales/vi/traces.json
 create mode 100644 ui/web/src/i18n/locales/vi/tts.json
 create mode 100644 ui/web/src/i18n/locales/vi/usage.json
 create mode 100644 ui/web/src/i18n/locales/zh/agents.json
 create mode 100644 ui/web/src/i18n/locales/zh/approvals.json
 create mode 100644 ui/web/src/i18n/locales/zh/channels.json
 create mode 100644 ui/web/src/i18n/locales/zh/chat.json
 create mode 100644 ui/web/src/i18n/locales/zh/common.json
 create mode 100644 ui/web/src/i18n/locales/zh/cron.json
 create mode 100644 ui/web/src/i18n/locales/zh/delegations.json
 create mode 100644 ui/web/src/i18n/locales/zh/events.json
 create mode 100644 ui/web/src/i18n/locales/zh/login.json
 create mode 100644 ui/web/src/i18n/locales/zh/logs.json
 create mode 100644 ui/web/src/i18n/locales/zh/mcp.json
 create mode 100644 ui/web/src/i18n/locales/zh/memory.json
 create mode 100644 ui/web/src/i18n/locales/zh/nodes.json
 create mode 100644 ui/web/src/i18n/locales/zh/overview.json
 create mode 100644 ui/web/src/i18n/locales/zh/pending-messages.json
 create mode 100644 ui/web/src/i18n/locales/zh/providers.json
 create mode 100644 ui/web/src/i18n/locales/zh/sessions.json
 create mode 100644 ui/web/src/i18n/locales/zh/setup.json
 create mode 100644 ui/web/src/i18n/locales/zh/sidebar.json
 create mode 100644 ui/web/src/i18n/locales/zh/skills.json
 create mode 100644 ui/web/src/i18n/locales/zh/storage.json
 create mode 100644 ui/web/src/i18n/locales/zh/teams.json
 create mode 100644 ui/web/src/i18n/locales/zh/tools.json
 create mode 100644 ui/web/src/i18n/locales/zh/topbar.json
 create mode 100644 ui/web/src/i18n/locales/zh/traces.json
 create mode 100644 ui/web/src/i18n/locales/zh/tts.json
 create mode 100644 ui/web/src/i18n/locales/zh/usage.json

diff --git a/CLAUDE.md b/CLAUDE.md
index 7b5a54d2..acfc1b69 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -33,6 +33,7 @@ internal/
 ├── crypto/                   AES-256-GCM encryption for API keys
 ├── sandbox/                  Docker-based code sandbox
 ├── tts/                      Text-to-Speech (OpenAI, ElevenLabs, Edge, MiniMax)
+├── i18n/                     Message catalog: T(locale, key, args...) + per-locale catalogs (en/vi/zh)
 pkg/protocol/                 Wire types (frames, methods, errors, events)
 pkg/browser/                  Browser automation (Rod + CDP)
 migrations/                   PostgreSQL migration files
@@ -46,11 +47,12 @@ ui/web/                       React SPA (pnpm, Vite, Tailwind, Radix UI)
 - **Context files:** `agent_context_files` (agent-level) + `user_context_files` (per-user), routed via `ContextFileInterceptor`
 - **Providers:** Anthropic (native HTTP+SSE) and OpenAI-compat (generic). Both use `RetryDo()` for retries. Loads from `llm_providers` table with encrypted API keys
 - **Agent loop:** `RunRequest` → think→act→observe → `RunResult`. Events: `run.started`, `run.completed`, `chunk`, `tool.call`, `tool.result`. Auto-summarization at >75% context
-- **Context propagation:** `store.WithAgentType(ctx)`, `store.WithUserID(ctx)`, `store.WithAgentID(ctx)`
+- **Context propagation:** `store.WithAgentType(ctx)`, `store.WithUserID(ctx)`, `store.WithAgentID(ctx)`, `store.WithLocale(ctx)`
 - **WebSocket protocol (v3):** Frame types `req`/`res`/`event`. First request must be `connect`
 - **Config:** JSON5 at `GOCLAW_CONFIG` env. Secrets in `.env.local` or env vars, never in config.json
 - **Security:** Rate limiting, input guard (detection-only), CORS, shell deny patterns, SSRF protection, path traversal prevention, AES-256-GCM encryption. All security logs: `slog.Warn("security.*")`
 - **Telegram formatting:** LLM output → `SanitizeAssistantContent()` → `markdownToTelegramHTML()` → `chunkHTML()` → `sendHTML()`. Tables rendered as ASCII in `<pre>` tags
+- **i18n:** Web UI uses `i18next` with namespace-split locale files in `ui/web/src/i18n/locales/{lang}/`. Backend uses `internal/i18n` message catalog with `i18n.T(locale, key, args...)`. Locale propagated via `store.WithLocale(ctx)` — WS `connect` param `locale`, HTTP `Accept-Language` header. Supported: en (default), vi, zh. New user-facing strings: add key to `internal/i18n/keys.go`, add translations to all 3 catalog files. New UI strings: add key to all 3 locale dirs. Bootstrap templates (SOUL.md, etc.) stay English-only (LLM consumption).
 
 ## Running
 
@@ -78,3 +80,4 @@ Go conventions to follow:
 - Use `append(dst, src...)` instead of loop-based append
 - Always handle errors; don't ignore return values
 - **Migrations:** When adding a new SQL migration file in `migrations/`, bump `RequiredSchemaVersion` in `internal/upgrade/version.go` to match the new migration number
+- **i18n strings:** When adding user-facing error messages, add key to `internal/i18n/keys.go` and translations to `catalog_en.go`, `catalog_vi.go`, `catalog_zh.go`. For UI strings, add to all locale JSON files in `ui/web/src/i18n/locales/{en,vi,zh}/`
diff --git a/internal/gateway/client.go b/internal/gateway/client.go
index a22a9ab4..ce5b7457 100644
--- a/internal/gateway/client.go
+++ b/internal/gateway/client.go
@@ -26,6 +26,8 @@ type Client struct {
 	connectedAt time.Time // when the client connected
 	remoteAddr  string    // peer IP (extracted from proxy headers or RemoteAddr)
 
+	locale string // user's preferred locale (e.g. "en", "vi", "zh")
+
 	// Browser pairing state
 	pairingCode     string // 8-char code if pending approval
 	pairingPending  bool   // true while waiting for admin approval
diff --git a/internal/gateway/methods/agent_links.go b/internal/gateway/methods/agent_links.go
index cb77d397..d3ab6b15 100644
--- a/internal/gateway/methods/agent_links.go
+++ b/internal/gateway/methods/agent_links.go
@@ -9,6 +9,7 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/agent"
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -39,20 +40,21 @@ type linksListParams struct {
 	Direction string `json:"direction"` // "from" (default), "to", "all"
 }
 
-func (m *AgentLinksMethods) handleList(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentLinksMethods) handleList(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.linkStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "agent links not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgLinksNotConfigured)))
 		return
 	}
 
 	var params linksListParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.AgentID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "agentId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "agentId")))
 		return
 	}
 
@@ -62,7 +64,6 @@ func (m *AgentLinksMethods) handleList(_ context.Context, client *gateway.Client
 		return
 	}
 
-	ctx := context.Background()
 	var links []store.AgentLinkData
 
 	switch params.Direction {
@@ -104,20 +105,21 @@ type linksCreateParams struct {
 	Settings      json.RawMessage `json:"settings"`
 }
 
-func (m *AgentLinksMethods) handleCreate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentLinksMethods) handleCreate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.linkStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "agent links not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgLinksNotConfigured)))
 		return
 	}
 
 	var params linksCreateParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.SourceAgent == "" || params.TargetAgent == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "sourceAgent and targetAgent are required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "sourceAgent and targetAgent")))
 		return
 	}
 
@@ -126,7 +128,7 @@ func (m *AgentLinksMethods) handleCreate(_ context.Context, client *gateway.Clie
 		direction = store.LinkDirectionOutbound
 	}
 	if direction != store.LinkDirectionOutbound && direction != store.LinkDirectionInbound && direction != store.LinkDirectionBidirectional {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "direction must be outbound, inbound, or bidirectional"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidDirection)))
 		return
 	}
 
@@ -142,13 +144,13 @@ func (m *AgentLinksMethods) handleCreate(_ context.Context, client *gateway.Clie
 	}
 
 	if sourceAgent.ID == targetAgent.ID {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "source and target must be different agents"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgSourceTargetSame)))
 		return
 	}
 
 	// Delegation targets must be predefined agents (open agents have no agent-level context files)
 	if targetAgent.AgentType == store.AgentTypeOpen {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "cannot delegate to open agents — only predefined agents can be delegation targets"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgCannotDelegateOpen)))
 		return
 	}
 
@@ -168,9 +170,8 @@ func (m *AgentLinksMethods) handleCreate(_ context.Context, client *gateway.Clie
 		CreatedBy:     client.UserID(),
 	}
 
-	ctx := context.Background()
 	if err := m.linkStore.CreateLink(ctx, link); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to create link: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToCreate, "link", err.Error())))
 		return
 	}
 
@@ -217,33 +218,34 @@ type linksUpdateParams struct {
 	Status        string          `json:"status"`
 }
 
-func (m *AgentLinksMethods) handleUpdate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentLinksMethods) handleUpdate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.linkStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "agent links not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgLinksNotConfigured)))
 		return
 	}
 
 	var params linksUpdateParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.LinkID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "linkId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "linkId")))
 		return
 	}
 
 	linkID, err := uuid.Parse(params.LinkID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid linkId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "linkId")))
 		return
 	}
 
 	updates := map[string]any{}
 	if params.Direction != "" {
 		if params.Direction != store.LinkDirectionOutbound && params.Direction != store.LinkDirectionInbound && params.Direction != store.LinkDirectionBidirectional {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "direction must be outbound, inbound, or bidirectional"))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidDirection)))
 			return
 		}
 		updates["direction"] = params.Direction
@@ -259,20 +261,19 @@ func (m *AgentLinksMethods) handleUpdate(_ context.Context, client *gateway.Clie
 	}
 	if params.Status != "" {
 		if params.Status != store.LinkStatusActive && params.Status != store.LinkStatusDisabled {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "status must be active or disabled"))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidLinkStatus)))
 			return
 		}
 		updates["status"] = params.Status
 	}
 
 	if len(updates) == 0 {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "no updates provided"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgNoUpdatesProvided)))
 		return
 	}
 
-	ctx := context.Background()
 	if err := m.linkStore.UpdateLink(ctx, linkID, updates); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to update link: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToUpdate, "link", err.Error())))
 		return
 	}
 
@@ -311,36 +312,35 @@ type linksDeleteParams struct {
 	LinkID string `json:"linkId"`
 }
 
-func (m *AgentLinksMethods) handleDelete(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentLinksMethods) handleDelete(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.linkStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "agent links not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgLinksNotConfigured)))
 		return
 	}
 
 	var params linksDeleteParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.LinkID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "linkId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "linkId")))
 		return
 	}
 
 	linkID, err := uuid.Parse(params.LinkID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid linkId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "linkId")))
 		return
 	}
 
-	ctx := context.Background()
-
 	// Fetch link before deleting to get agent IDs for cache invalidation
 	link, _ := m.linkStore.GetLink(ctx, linkID)
 
 	if err := m.linkStore.DeleteLink(ctx, linkID); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to delete link: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToDelete, "link", err.Error())))
 		return
 	}
 
diff --git a/internal/gateway/methods/agents.go b/internal/gateway/methods/agents.go
index 5992f053..25cfb8d7 100644
--- a/internal/gateway/methods/agents.go
+++ b/internal/gateway/methods/agents.go
@@ -8,6 +8,7 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/agent"
 	"github.com/nextlevelbuilder/goclaw/internal/config"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/internal/tools"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
@@ -103,9 +104,10 @@ func (m *AgentsMethods) handleAgentWait(_ context.Context, client *gateway.Clien
 
 func (m *AgentsMethods) handleList(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
 	if m.agentStore != nil {
+		locale := store.LocaleFromContext(ctx)
 		userID := client.UserID()
 		if userID == "" {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "user context required"))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgUserCtxRequired)))
 			return
 		}
 
@@ -118,7 +120,7 @@ func (m *AgentsMethods) handleList(ctx context.Context, client *gateway.Client,
 		}
 		if err != nil {
 			slog.Warn("agents.list: store query failed", "error", err)
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to list agents"))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToList, "agents")))
 			return
 		}
 
diff --git a/internal/gateway/methods/agents_create.go b/internal/gateway/methods/agents_create.go
index c54cc416..b4049894 100644
--- a/internal/gateway/methods/agents_create.go
+++ b/internal/gateway/methods/agents_create.go
@@ -11,6 +11,7 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/bootstrap"
 	"github.com/nextlevelbuilder/goclaw/internal/config"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -18,7 +19,8 @@ import (
 // --- agents.create ---
 // Matching TS src/gateway/server-methods/agents.ts:216-287
 
-func (m *AgentsMethods) handleCreate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentsMethods) handleCreate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Name      string   `json:"name"`
 		Workspace string   `json:"workspace"`
@@ -40,7 +42,7 @@ func (m *AgentsMethods) handleCreate(_ context.Context, client *gateway.Client,
 	}
 
 	if params.Name == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name")))
 		return
 	}
 
@@ -51,7 +53,7 @@ func (m *AgentsMethods) handleCreate(_ context.Context, client *gateway.Client,
 
 	agentID := config.NormalizeAgentID(params.Name)
 	if agentID == "default" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "cannot create agent with reserved id 'default'"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, "cannot create agent with reserved id 'default'")))
 		return
 	}
 
@@ -69,7 +71,7 @@ func (m *AgentsMethods) handleCreate(_ context.Context, client *gateway.Client,
 
 		// Check if agent already exists in DB
 		if existing, _ := m.agentStore.GetByKey(ctx, agentID); existing != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "agent already exists: "+agentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgAlreadyExists, "agent", agentID)))
 			return
 		}
 
@@ -98,7 +100,7 @@ func (m *AgentsMethods) handleCreate(_ context.Context, client *gateway.Client,
 			OtherConfig:      params.OtherConfig,
 		}
 		if err := m.agentStore.Create(ctx, agentData); err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, fmt.Sprintf("failed to create agent: %v", err)))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToCreate, "agent", fmt.Sprintf("%v", err))))
 			return
 		}
 
@@ -120,7 +122,7 @@ func (m *AgentsMethods) handleCreate(_ context.Context, client *gateway.Client,
 	} else {
 		// --- Fallback: config.json + filesystem ---
 		if _, ok := m.cfg.Agents.List[agentID]; ok {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "agent already exists: "+agentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgAlreadyExists, "agent", agentID)))
 			return
 		}
 
@@ -140,7 +142,7 @@ func (m *AgentsMethods) handleCreate(_ context.Context, client *gateway.Client,
 		m.cfg.Agents.List[agentID] = spec
 
 		if err := config.Save(m.cfgPath, m.cfg); err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to save config: "+err.Error()))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "config", err.Error())))
 			return
 		}
 
diff --git a/internal/gateway/methods/agents_delete.go b/internal/gateway/methods/agents_delete.go
index 6c63444c..98459ab8 100644
--- a/internal/gateway/methods/agents_delete.go
+++ b/internal/gateway/methods/agents_delete.go
@@ -8,13 +8,16 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/config"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
 
 // --- agents.delete ---
 // Matching TS src/gateway/server-methods/agents.ts:347-398
 
-func (m *AgentsMethods) handleDelete(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentsMethods) handleDelete(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		AgentID     string `json:"agentId"`
 		DeleteFiles bool   `json:"deleteFiles"`
@@ -25,11 +28,11 @@ func (m *AgentsMethods) handleDelete(_ context.Context, client *gateway.Client,
 	}
 
 	if params.AgentID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "agentId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "agentId")))
 		return
 	}
 	if params.AgentID == "default" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "cannot delete the default agent"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgCannotDeleteDefault)))
 		return
 	}
 
@@ -40,12 +43,12 @@ func (m *AgentsMethods) handleDelete(_ context.Context, client *gateway.Client,
 		ctx := context.Background()
 		ag, err := m.agentStore.GetByKey(ctx, params.AgentID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "agent not found: "+params.AgentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgAgentNotFound, params.AgentID)))
 			return
 		}
 
 		if err := m.agentStore.Delete(ctx, ag.ID); err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, fmt.Sprintf("failed to delete agent: %v", err)))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToDelete, "agent", fmt.Sprintf("%v", err))))
 			return
 		}
 
@@ -60,7 +63,7 @@ func (m *AgentsMethods) handleDelete(_ context.Context, client *gateway.Client,
 		// --- Fallback: config.json ---
 		spec, ok := m.cfg.Agents.List[params.AgentID]
 		if !ok {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "agent not found: "+params.AgentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgAgentNotFound, params.AgentID)))
 			return
 		}
 
@@ -79,7 +82,7 @@ func (m *AgentsMethods) handleDelete(_ context.Context, client *gateway.Client,
 		m.agents.Remove(params.AgentID)
 
 		if err := config.Save(m.cfgPath, m.cfg); err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to save config: "+err.Error()))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "config", err.Error())))
 			return
 		}
 
diff --git a/internal/gateway/methods/agents_files.go b/internal/gateway/methods/agents_files.go
index b11c2bb0..f723ddb8 100644
--- a/internal/gateway/methods/agents_files.go
+++ b/internal/gateway/methods/agents_files.go
@@ -9,6 +9,7 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/bootstrap"
 	"github.com/nextlevelbuilder/goclaw/internal/config"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -23,7 +24,8 @@ var allowedAgentFiles = []string{
 // --- agents.files.list ---
 // Matching TS src/gateway/server-methods/agents.ts:399-422
 
-func (m *AgentsMethods) handleFilesList(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentsMethods) handleFilesList(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params agentParams
 	if req.Params != nil {
 		json.Unmarshal(req.Params, &params)
@@ -37,13 +39,13 @@ func (m *AgentsMethods) handleFilesList(_ context.Context, client *gateway.Clien
 		ctx := context.Background()
 		ag, err := m.agentStore.GetByKey(ctx, params.AgentID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "agent not found: "+params.AgentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgAgentNotFound, params.AgentID)))
 			return
 		}
 
 		dbFiles, err := m.agentStore.GetAgentContextFiles(ctx, ag.ID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to list files: "+err.Error()))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToList, "files")))
 			return
 		}
 
@@ -110,7 +112,8 @@ func (m *AgentsMethods) handleFilesList(_ context.Context, client *gateway.Clien
 // --- agents.files.get ---
 // Matching TS src/gateway/server-methods/agents.ts:423-473
 
-func (m *AgentsMethods) handleFilesGet(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentsMethods) handleFilesGet(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		AgentID string `json:"agentId"`
 		Name    string `json:"name"`
@@ -122,11 +125,11 @@ func (m *AgentsMethods) handleFilesGet(_ context.Context, client *gateway.Client
 		params.AgentID = "default"
 	}
 	if params.Name == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name")))
 		return
 	}
 	if !isAllowedFile(params.Name) {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "file not allowed: "+params.Name))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, "file not allowed: "+params.Name)))
 		return
 	}
 
@@ -135,13 +138,13 @@ func (m *AgentsMethods) handleFilesGet(_ context.Context, client *gateway.Client
 		ctx := context.Background()
 		ag, err := m.agentStore.GetByKey(ctx, params.AgentID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "agent not found: "+params.AgentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgAgentNotFound, params.AgentID)))
 			return
 		}
 
 		dbFiles, err := m.agentStore.GetAgentContextFiles(ctx, ag.ID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to get files: "+err.Error()))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToList, "files")))
 			return
 		}
 
@@ -207,7 +210,8 @@ func (m *AgentsMethods) handleFilesGet(_ context.Context, client *gateway.Client
 // --- agents.files.set ---
 // Matching TS src/gateway/server-methods/agents.ts:474-515
 
-func (m *AgentsMethods) handleFilesSet(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentsMethods) handleFilesSet(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		AgentID string `json:"agentId"`
 		Name    string `json:"name"`
@@ -220,11 +224,11 @@ func (m *AgentsMethods) handleFilesSet(_ context.Context, client *gateway.Client
 		params.AgentID = "default"
 	}
 	if params.Name == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name")))
 		return
 	}
 	if !isAllowedFile(params.Name) {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "file not allowed: "+params.Name))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, "file not allowed: "+params.Name)))
 		return
 	}
 
@@ -233,12 +237,12 @@ func (m *AgentsMethods) handleFilesSet(_ context.Context, client *gateway.Client
 		ctx := context.Background()
 		ag, err := m.agentStore.GetByKey(ctx, params.AgentID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "agent not found: "+params.AgentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgAgentNotFound, params.AgentID)))
 			return
 		}
 
 		if err := m.agentStore.SetAgentContextFile(ctx, ag.ID, params.Name, params.Content); err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to write file: "+err.Error()))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "file", err.Error())))
 			return
 		}
 
@@ -267,7 +271,7 @@ func (m *AgentsMethods) handleFilesSet(_ context.Context, client *gateway.Client
 	p := filepath.Join(ws, params.Name)
 
 	if err := os.WriteFile(p, []byte(params.Content), 0644); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to write file: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "file", err.Error())))
 		return
 	}
 
diff --git a/internal/gateway/methods/agents_update.go b/internal/gateway/methods/agents_update.go
index 4fd59743..1416ce6f 100644
--- a/internal/gateway/methods/agents_update.go
+++ b/internal/gateway/methods/agents_update.go
@@ -10,13 +10,16 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/config"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
 
 // --- agents.update ---
 // Matching TS src/gateway/server-methods/agents.ts:288-346
 
-func (m *AgentsMethods) handleUpdate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *AgentsMethods) handleUpdate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		AgentID   string `json:"agentId"`
 		Name      string `json:"name"`
@@ -37,7 +40,7 @@ func (m *AgentsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 	}
 
 	if params.AgentID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "agentId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "agentId")))
 		return
 	}
 
@@ -46,7 +49,7 @@ func (m *AgentsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 		ctx := context.Background()
 		ag, err := m.agentStore.GetByKey(ctx, params.AgentID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "agent not found: "+params.AgentID))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgAgentNotFound, params.AgentID)))
 			return
 		}
 
@@ -87,7 +90,7 @@ func (m *AgentsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 
 		if len(updates) > 0 {
 			if err := m.agentStore.Update(ctx, ag.ID, updates); err != nil {
-				client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, fmt.Sprintf("failed to update agent: %v", err)))
+				client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToUpdate, "agent", fmt.Sprintf("%v", err))))
 				return
 			}
 		}
@@ -110,7 +113,7 @@ func (m *AgentsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 		spec, ok := m.cfg.Agents.List[params.AgentID]
 		if !ok {
 			if params.AgentID != "default" {
-				client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "agent not found: "+params.AgentID))
+				client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgAgentNotFound, params.AgentID)))
 				return
 			}
 		}
@@ -147,7 +150,7 @@ func (m *AgentsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 		}
 
 		if err := config.Save(m.cfgPath, m.cfg); err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to save config: "+err.Error()))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "config", err.Error())))
 			return
 		}
 	}
diff --git a/internal/gateway/methods/channel_instances.go b/internal/gateway/methods/channel_instances.go
index 6b64d2aa..7cc7799b 100644
--- a/internal/gateway/methods/channel_instances.go
+++ b/internal/gateway/methods/channel_instances.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -44,10 +45,11 @@ func (m *ChannelInstancesMethods) emitCacheInvalidate() {
 }
 
 func (m *ChannelInstancesMethods) handleList(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	instances, err := m.store.ListAll(ctx)
 	if err != nil {
 		slog.Error("channels.instances.list", "error", err)
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to list channel instances"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToList, "channel instances")))
 		return
 	}
 
@@ -63,6 +65,7 @@ func (m *ChannelInstancesMethods) handleList(ctx context.Context, client *gatewa
 }
 
 func (m *ChannelInstancesMethods) handleGet(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		ID string `json:"id"`
 	}
@@ -72,13 +75,13 @@ func (m *ChannelInstancesMethods) handleGet(ctx context.Context, client *gateway
 
 	id, err := uuid.Parse(params.ID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid instance ID"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "instance")))
 		return
 	}
 
 	inst, err := m.store.Get(ctx, id)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "instance not found"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgInstanceNotFound)))
 		return
 	}
 
@@ -86,6 +89,7 @@ func (m *ChannelInstancesMethods) handleGet(ctx context.Context, client *gateway
 }
 
 func (m *ChannelInstancesMethods) handleCreate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Name        string          `json:"name"`
 		DisplayName string          `json:"display_name"`
@@ -100,18 +104,18 @@ func (m *ChannelInstancesMethods) handleCreate(ctx context.Context, client *gate
 	}
 
 	if params.Name == "" || params.ChannelType == "" || params.AgentID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name, channel_type, and agent_id are required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name, channel_type, and agent_id")))
 		return
 	}
 
 	if !isValidChannelType(params.ChannelType) {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid channel_type"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidChannelType)))
 		return
 	}
 
 	agentID, err := uuid.Parse(params.AgentID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid agent_id"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "agent_id")))
 		return
 	}
 
@@ -132,7 +136,7 @@ func (m *ChannelInstancesMethods) handleCreate(ctx context.Context, client *gate
 
 	if err := m.store.Create(ctx, inst); err != nil {
 		slog.Error("channels.instances.create", "error", err)
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to create instance: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToCreate, "instance", err.Error())))
 		return
 	}
 
@@ -141,6 +145,7 @@ func (m *ChannelInstancesMethods) handleCreate(ctx context.Context, client *gate
 }
 
 func (m *ChannelInstancesMethods) handleUpdate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		ID      string          `json:"id"`
 		Updates json.RawMessage `json:"updates"`
@@ -151,19 +156,19 @@ func (m *ChannelInstancesMethods) handleUpdate(ctx context.Context, client *gate
 
 	id, err := uuid.Parse(params.ID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid instance ID"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "instance")))
 		return
 	}
 
 	var updates map[string]interface{}
 	if err := json.Unmarshal(params.Updates, &updates); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid updates"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidUpdates)))
 		return
 	}
 
 	if err := m.store.Update(ctx, id, updates); err != nil {
 		slog.Error("channels.instances.update", "error", err)
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to update instance: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToUpdate, "instance", err.Error())))
 		return
 	}
 
@@ -172,6 +177,7 @@ func (m *ChannelInstancesMethods) handleUpdate(ctx context.Context, client *gate
 }
 
 func (m *ChannelInstancesMethods) handleDelete(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		ID string `json:"id"`
 	}
@@ -181,24 +187,24 @@ func (m *ChannelInstancesMethods) handleDelete(ctx context.Context, client *gate
 
 	id, err := uuid.Parse(params.ID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid instance ID"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "instance")))
 		return
 	}
 
 	// Look up instance to check if it's a default (seeded) instance.
 	inst, err := m.store.Get(ctx, id)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "instance not found"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInstanceNotFound)))
 		return
 	}
 	if store.IsDefaultChannelInstance(inst.Name) {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "cannot delete default channel instance"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgCannotDeleteDefaultInst)))
 		return
 	}
 
 	if err := m.store.Delete(ctx, id); err != nil {
 		slog.Error("channels.instances.delete", "error", err)
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to delete instance: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToDelete, "instance", err.Error())))
 		return
 	}
 
diff --git a/internal/gateway/methods/channels.go b/internal/gateway/methods/channels.go
index a0a2d053..f40c7d8a 100644
--- a/internal/gateway/methods/channels.go
+++ b/internal/gateway/methods/channels.go
@@ -5,6 +5,8 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/channels"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
 
@@ -39,7 +41,8 @@ func (m *ChannelsMethods) handleStatus(_ context.Context, client *gateway.Client
 	}))
 }
 
-func (m *ChannelsMethods) handleToggle(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *ChannelsMethods) handleToggle(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	// Channel toggling requires restarting the channel, which is a Phase 3 feature.
-	client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "channels.toggle not yet implemented"))
+	client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgNotImplemented, "channels.toggle")))
 }
diff --git a/internal/gateway/methods/chat.go b/internal/gateway/methods/chat.go
index d30965f8..162ad1e9 100644
--- a/internal/gateway/methods/chat.go
+++ b/internal/gateway/methods/chat.go
@@ -10,6 +10,7 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/channels/media"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/providers"
 	"github.com/nextlevelbuilder/goclaw/internal/sessions"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
@@ -44,6 +45,7 @@ type chatSendParams struct {
 }
 
 func (m *ChatMethods) handleSend(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	// Rate limit check per user/client
 	if m.rateLimiter != nil && m.rateLimiter.Enabled() {
 		key := client.UserID()
@@ -51,14 +53,14 @@ func (m *ChatMethods) handleSend(ctx context.Context, client *gateway.Client, re
 			key = client.ID()
 		}
 		if !m.rateLimiter.Allow(key) {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "rate limit exceeded — please wait before sending more messages"))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRateLimitExceeded)))
 			return
 		}
 	}
 
 	var params chatSendParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
@@ -83,7 +85,7 @@ func (m *ChatMethods) handleSend(ctx context.Context, client *gateway.Client, re
 
 	userID := client.UserID()
 	if userID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "user_id is required in managed mode — provide it in the connect handshake"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgUserIDRequired)))
 		return
 	}
 
@@ -171,9 +173,10 @@ type chatHistoryParams struct {
 }
 
 func (m *ChatMethods) handleHistory(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params chatHistoryParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
@@ -195,23 +198,24 @@ func (m *ChatMethods) handleHistory(ctx context.Context, client *gateway.Client,
 
 // handleInject injects a message into a session transcript without running the agent.
 // Matching TS chat.inject (src/gateway/server-methods/chat.ts:686-746).
-func (m *ChatMethods) handleInject(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *ChatMethods) handleInject(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		SessionKey string `json:"sessionKey"`
 		Message    string `json:"message"`
 		Label      string `json:"label"`
 	}
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.SessionKey == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "sessionKey is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "sessionKey")))
 		return
 	}
 	if params.Message == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "message is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgMsgRequired)))
 		return
 	}
 
@@ -249,18 +253,19 @@ func (m *ChatMethods) handleInject(_ context.Context, client *gateway.Client, re
 // Response:
 //
 //	{ ok: true, aborted: bool, runIds: []string }
-func (m *ChatMethods) handleAbort(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *ChatMethods) handleAbort(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		RunID      string `json:"runId"`
 		SessionKey string `json:"sessionKey"`
 	}
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.SessionKey == "" && params.RunID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "sessionKey or runId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "sessionKey or runId")))
 		return
 	}
 
diff --git a/internal/gateway/methods/config.go b/internal/gateway/methods/config.go
index e84240ec..0543b803 100644
--- a/internal/gateway/methods/config.go
+++ b/internal/gateway/methods/config.go
@@ -10,6 +10,7 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/config"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -45,6 +46,7 @@ func (m *ConfigMethods) handleGet(_ context.Context, client *gateway.Client, req
 // handleApply replaces the entire config with the provided JSON5 raw content.
 // Matching TS config.apply (src/gateway/server-methods/config.ts:435-486).
 func (m *ConfigMethods) handleApply(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Raw      string `json:"raw"`
 		BaseHash string `json:"baseHash"`
@@ -54,20 +56,20 @@ func (m *ConfigMethods) handleApply(ctx context.Context, client *gateway.Client,
 	}
 
 	if params.Raw == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "raw config is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRawConfigRequired)))
 		return
 	}
 
 	// Optimistic concurrency: validate hash if provided
 	if params.BaseHash != "" && params.BaseHash != m.cfg.Hash() {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "config has changed (hash mismatch)"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgConfigHashMismatch)))
 		return
 	}
 
 	// Parse the new config
 	newCfg := config.Default()
 	if err := json5.Unmarshal([]byte(params.Raw), newCfg); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid config: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, err.Error())))
 		return
 	}
 
@@ -77,7 +79,7 @@ func (m *ConfigMethods) handleApply(ctx context.Context, client *gateway.Client,
 
 	// Save to disk
 	if err := config.Save(m.cfgPath, newCfg); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to save config: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "config", err.Error())))
 		return
 	}
 
@@ -103,6 +105,7 @@ func (m *ConfigMethods) handleApply(ctx context.Context, client *gateway.Client,
 // handlePatch merges a partial config update into the current config.
 // Matching TS config.patch (src/gateway/server-methods/config.ts:321-434).
 func (m *ConfigMethods) handlePatch(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Raw      string `json:"raw"`
 		BaseHash string `json:"baseHash"`
@@ -112,33 +115,33 @@ func (m *ConfigMethods) handlePatch(ctx context.Context, client *gateway.Client,
 	}
 
 	if params.Raw == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "raw patch is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRawPatchRequired)))
 		return
 	}
 
 	// Optimistic concurrency
 	if params.BaseHash != "" && params.BaseHash != m.cfg.Hash() {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "config has changed (hash mismatch)"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgConfigHashMismatch)))
 		return
 	}
 
 	// Merge strategy: serialize current -> deserialize patch on top -> save
 	currentJSON, err := json.Marshal(m.cfg)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to serialize current config"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgInternalError, "failed to serialize current config")))
 		return
 	}
 
 	// Start from current config as base
 	merged := config.Default()
 	if err := json.Unmarshal(currentJSON, merged); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to clone config"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgInternalError, "failed to clone config")))
 		return
 	}
 
 	// Apply patch on top
 	if err := json5.Unmarshal([]byte(params.Raw), merged); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid patch: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, err.Error())))
 		return
 	}
 
@@ -148,7 +151,7 @@ func (m *ConfigMethods) handlePatch(ctx context.Context, client *gateway.Client,
 
 	// Save to disk
 	if err := config.Save(m.cfgPath, merged); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to save config: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToSave, "config", err.Error())))
 		return
 	}
 
diff --git a/internal/gateway/methods/cron.go b/internal/gateway/methods/cron.go
index 5506a5aa..1968f318 100644
--- a/internal/gateway/methods/cron.go
+++ b/internal/gateway/methods/cron.go
@@ -7,6 +7,7 @@ import (
 	"regexp"
 
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -49,30 +50,31 @@ func (m *CronMethods) handleList(_ context.Context, client *gateway.Client, req
 	}))
 }
 
-func (m *CronMethods) handleCreate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *CronMethods) handleCreate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
-		Name     string        `json:"name"`
+		Name     string             `json:"name"`
 		Schedule store.CronSchedule `json:"schedule"`
-		Message  string        `json:"message"`
-		Deliver  bool          `json:"deliver"`
-		Channel  string        `json:"channel"`
-		To       string        `json:"to"`
-		AgentID  string        `json:"agentId"`
+		Message  string             `json:"message"`
+		Deliver  bool               `json:"deliver"`
+		Channel  string             `json:"channel"`
+		To       string             `json:"to"`
+		AgentID  string             `json:"agentId"`
 	}
 	if req.Params != nil {
 		json.Unmarshal(req.Params, &params)
 	}
 
 	if params.Name == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name")))
 		return
 	}
 	if !cronSlugRe.MatchString(params.Name) {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name must be a valid slug (lowercase letters, numbers, hyphens only)"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidSlug, "name")))
 		return
 	}
 	if params.Message == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "message is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgMsgRequired)))
 		return
 	}
 
@@ -87,7 +89,8 @@ func (m *CronMethods) handleCreate(_ context.Context, client *gateway.Client, re
 	}))
 }
 
-func (m *CronMethods) handleDelete(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *CronMethods) handleDelete(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		JobID string `json:"jobId"`
 	}
@@ -96,7 +99,7 @@ func (m *CronMethods) handleDelete(_ context.Context, client *gateway.Client, re
 	}
 
 	if params.JobID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "jobId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "jobId")))
 		return
 	}
 
@@ -110,7 +113,8 @@ func (m *CronMethods) handleDelete(_ context.Context, client *gateway.Client, re
 	}))
 }
 
-func (m *CronMethods) handleToggle(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *CronMethods) handleToggle(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		JobID   string `json:"jobId"`
 		Enabled bool   `json:"enabled"`
@@ -120,7 +124,7 @@ func (m *CronMethods) handleToggle(_ context.Context, client *gateway.Client, re
 	}
 
 	if params.JobID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "jobId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "jobId")))
 		return
 	}
 
@@ -139,10 +143,11 @@ func (m *CronMethods) handleStatus(_ context.Context, client *gateway.Client, re
 	client.SendResponse(protocol.NewOKResponse(req.ID, m.service.Status()))
 }
 
-func (m *CronMethods) handleUpdate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *CronMethods) handleUpdate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
-		JobID string        `json:"jobId"`
-		ID    string        `json:"id"` // alias (matching TS)
+		JobID string            `json:"jobId"`
+		ID    string            `json:"id"` // alias (matching TS)
 		Patch store.CronJobPatch `json:"patch"`
 	}
 	if req.Params != nil {
@@ -154,7 +159,7 @@ func (m *CronMethods) handleUpdate(_ context.Context, client *gateway.Client, re
 		jobID = params.ID
 	}
 	if jobID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "jobId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "jobId")))
 		return
 	}
 
@@ -169,7 +174,8 @@ func (m *CronMethods) handleUpdate(_ context.Context, client *gateway.Client, re
 	}))
 }
 
-func (m *CronMethods) handleRun(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *CronMethods) handleRun(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		JobID string `json:"jobId"`
 		ID    string `json:"id"`
@@ -184,7 +190,7 @@ func (m *CronMethods) handleRun(_ context.Context, client *gateway.Client, req *
 		jobID = params.ID
 	}
 	if jobID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "jobId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "jobId")))
 		return
 	}
 
@@ -193,7 +199,7 @@ func (m *CronMethods) handleRun(_ context.Context, client *gateway.Client, req *
 	// Validate job exists before responding
 	_, ok := m.service.GetJob(jobID)
 	if !ok {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "job not found"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgJobNotFound)))
 		return
 	}
 
diff --git a/internal/gateway/methods/delegations.go b/internal/gateway/methods/delegations.go
index dd2aea79..14b1811f 100644
--- a/internal/gateway/methods/delegations.go
+++ b/internal/gateway/methods/delegations.go
@@ -7,6 +7,7 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -25,9 +26,10 @@ func (m *DelegationsMethods) Register(router *gateway.MethodRouter) {
 	router.Register(protocol.MethodDelegationsGet, m.handleGet)
 }
 
-func (m *DelegationsMethods) handleList(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *DelegationsMethods) handleList(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "delegations not available"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgDelegationsUnavailable)))
 		return
 	}
 
@@ -67,7 +69,6 @@ func (m *DelegationsMethods) handleList(_ context.Context, client *gateway.Clien
 		}
 	}
 
-	ctx := context.Background()
 	records, total, err := m.teamStore.ListDelegationHistory(ctx, opts)
 	if err != nil {
 		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, err.Error()))
@@ -92,9 +93,10 @@ func (m *DelegationsMethods) handleList(_ context.Context, client *gateway.Clien
 	}))
 }
 
-func (m *DelegationsMethods) handleGet(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *DelegationsMethods) handleGet(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "delegations not available"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgDelegationsUnavailable)))
 		return
 	}
 
@@ -105,17 +107,16 @@ func (m *DelegationsMethods) handleGet(_ context.Context, client *gateway.Client
 		_ = json.Unmarshal(req.Params, &params)
 	}
 	if params.ID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "id is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "id")))
 		return
 	}
 
 	id, err := uuid.Parse(params.ID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid id"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "id")))
 		return
 	}
 
-	ctx := context.Background()
 	record, err := m.teamStore.GetDelegationHistory(ctx, id)
 	if err != nil {
 		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, err.Error()))
diff --git a/internal/gateway/methods/exec_approval.go b/internal/gateway/methods/exec_approval.go
index c89971b8..76ffd644 100644
--- a/internal/gateway/methods/exec_approval.go
+++ b/internal/gateway/methods/exec_approval.go
@@ -5,6 +5,8 @@ import (
 	"encoding/json"
 
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/internal/tools"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -55,22 +57,23 @@ func (m *ExecApprovalMethods) handleList(_ context.Context, client *gateway.Clie
 	}))
 }
 
-func (m *ExecApprovalMethods) handleApprove(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *ExecApprovalMethods) handleApprove(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.manager == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "exec approval is not enabled"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgExecApprovalDisabled)))
 		return
 	}
 
 	var params struct {
-		ID    string `json:"id"`
-		Always bool  `json:"always"` // true = allow-always, false = allow-once
+		ID     string `json:"id"`
+		Always bool   `json:"always"` // true = allow-always, false = allow-once
 	}
 	if req.Params != nil {
 		json.Unmarshal(req.Params, &params)
 	}
 
 	if params.ID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "id is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "id")))
 		return
 	}
 
@@ -90,9 +93,10 @@ func (m *ExecApprovalMethods) handleApprove(_ context.Context, client *gateway.C
 	}))
 }
 
-func (m *ExecApprovalMethods) handleDeny(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *ExecApprovalMethods) handleDeny(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.manager == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "exec approval is not enabled"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgExecApprovalDisabled)))
 		return
 	}
 
@@ -104,7 +108,7 @@ func (m *ExecApprovalMethods) handleDeny(_ context.Context, client *gateway.Clie
 	}
 
 	if params.ID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "id is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "id")))
 		return
 	}
 
diff --git a/internal/gateway/methods/logs.go b/internal/gateway/methods/logs.go
index 18d3795b..21675a35 100644
--- a/internal/gateway/methods/logs.go
+++ b/internal/gateway/methods/logs.go
@@ -6,6 +6,8 @@ import (
 	"log/slog"
 
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
 
@@ -22,7 +24,8 @@ func (m *LogsMethods) Register(router *gateway.MethodRouter) {
 	router.Register(protocol.MethodLogsTail, m.handleTail)
 }
 
-func (m *LogsMethods) handleTail(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *LogsMethods) handleTail(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Action string `json:"action"`
 		Level  string `json:"level"` // "debug", "info", "warn", "error" (default: "info")
@@ -48,7 +51,7 @@ func (m *LogsMethods) handleTail(_ context.Context, client *gateway.Client, req
 		client.SendResponse(protocol.NewErrorResponse(
 			req.ID,
 			protocol.ErrInvalidRequest,
-			"action must be 'start' or 'stop'",
+			i18n.T(locale, i18n.MsgInvalidLogAction),
 		))
 	}
 }
diff --git a/internal/gateway/methods/pairing.go b/internal/gateway/methods/pairing.go
index 9b1b3e44..f519832c 100644
--- a/internal/gateway/methods/pairing.go
+++ b/internal/gateway/methods/pairing.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -46,7 +47,8 @@ func (m *PairingMethods) Register(router *gateway.MethodRouter) {
 	router.Register(protocol.MethodBrowserPairingStatus, m.handleBrowserPairingStatus)
 }
 
-func (m *PairingMethods) handleRequest(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *PairingMethods) handleRequest(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		SenderID  string `json:"senderId"`
 		Channel   string `json:"channel"`
@@ -58,7 +60,7 @@ func (m *PairingMethods) handleRequest(_ context.Context, client *gateway.Client
 	}
 
 	if params.SenderID == "" || params.Channel == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "senderId and channel are required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgSenderChannelRequired)))
 		return
 	}
 
@@ -78,6 +80,7 @@ func (m *PairingMethods) handleRequest(_ context.Context, client *gateway.Client
 }
 
 func (m *PairingMethods) handleApprove(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Code       string `json:"code"`
 		ApprovedBy string `json:"approvedBy"`
@@ -87,7 +90,7 @@ func (m *PairingMethods) handleApprove(ctx context.Context, client *gateway.Clie
 	}
 
 	if params.Code == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "code is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgCodeRequired)))
 		return
 	}
 	if params.ApprovedBy == "" {
@@ -115,7 +118,8 @@ func (m *PairingMethods) handleApprove(ctx context.Context, client *gateway.Clie
 	}))
 }
 
-func (m *PairingMethods) handleDeny(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *PairingMethods) handleDeny(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Code string `json:"code"`
 	}
@@ -124,7 +128,7 @@ func (m *PairingMethods) handleDeny(_ context.Context, client *gateway.Client, r
 	}
 
 	if params.Code == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "code is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgCodeRequired)))
 		return
 	}
 
@@ -152,7 +156,8 @@ func (m *PairingMethods) handleList(_ context.Context, client *gateway.Client, r
 	}))
 }
 
-func (m *PairingMethods) handleRevoke(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *PairingMethods) handleRevoke(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		SenderID string `json:"senderId"`
 		Channel  string `json:"channel"`
@@ -162,7 +167,7 @@ func (m *PairingMethods) handleRevoke(_ context.Context, client *gateway.Client,
 	}
 
 	if params.SenderID == "" || params.Channel == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "senderId and channel are required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgSenderChannelRequired)))
 		return
 	}
 
@@ -193,7 +198,8 @@ func (m *PairingMethods) handleRevoke(_ context.Context, client *gateway.Client,
 
 // handleBrowserPairingStatus lets a pending browser client check if its pairing code has been approved.
 // Called by unauthenticated clients during the browser pairing flow.
-func (m *PairingMethods) handleBrowserPairingStatus(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *PairingMethods) handleBrowserPairingStatus(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		SenderID string `json:"sender_id"`
 	}
@@ -202,7 +208,7 @@ func (m *PairingMethods) handleBrowserPairingStatus(_ context.Context, client *g
 	}
 
 	if params.SenderID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "sender_id is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgSenderIDRequired)))
 		return
 	}
 
diff --git a/internal/gateway/methods/send.go b/internal/gateway/methods/send.go
index 0d0c190a..589cd25d 100644
--- a/internal/gateway/methods/send.go
+++ b/internal/gateway/methods/send.go
@@ -6,6 +6,8 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
 
@@ -23,7 +25,8 @@ func (m *SendMethods) Register(router *gateway.MethodRouter) {
 	router.Register(protocol.MethodSend, m.handleSend)
 }
 
-func (m *SendMethods) handleSend(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *SendMethods) handleSend(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Channel string `json:"channel"`
 		To      string `json:"to"`
@@ -34,15 +37,15 @@ func (m *SendMethods) handleSend(_ context.Context, client *gateway.Client, req
 	}
 
 	if params.Channel == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "channel is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "channel")))
 		return
 	}
 	if params.To == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "to is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "to")))
 		return
 	}
 	if params.Message == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "message is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgMsgRequired)))
 		return
 	}
 
diff --git a/internal/gateway/methods/sessions.go b/internal/gateway/methods/sessions.go
index ec929841..965d72d0 100644
--- a/internal/gateway/methods/sessions.go
+++ b/internal/gateway/methods/sessions.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -59,10 +60,11 @@ type sessionKeyParams struct {
 	Key string `json:"key"`
 }
 
-func (m *SessionsMethods) handlePreview(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *SessionsMethods) handlePreview(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params sessionKeyParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
@@ -78,7 +80,8 @@ func (m *SessionsMethods) handlePreview(_ context.Context, client *gateway.Clien
 
 // handlePatch updates session metadata fields.
 // Matching TS sessions.patch (src/gateway/server-methods/sessions.ts:237-287).
-func (m *SessionsMethods) handlePatch(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *SessionsMethods) handlePatch(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Key      string            `json:"key"`
 		Label    *string           `json:"label,omitempty"`
@@ -86,12 +89,12 @@ func (m *SessionsMethods) handlePatch(_ context.Context, client *gateway.Client,
 		Metadata map[string]string `json:"metadata,omitempty"`
 	}
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.Key == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "key is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "key")))
 		return
 	}
 
@@ -119,10 +122,11 @@ func (m *SessionsMethods) handlePatch(_ context.Context, client *gateway.Client,
 	}))
 }
 
-func (m *SessionsMethods) handleDelete(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *SessionsMethods) handleDelete(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params sessionKeyParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
@@ -136,10 +140,11 @@ func (m *SessionsMethods) handleDelete(_ context.Context, client *gateway.Client
 	}))
 }
 
-func (m *SessionsMethods) handleReset(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *SessionsMethods) handleReset(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params sessionKeyParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
diff --git a/internal/gateway/methods/skills.go b/internal/gateway/methods/skills.go
index 313fe816..3332b003 100644
--- a/internal/gateway/methods/skills.go
+++ b/internal/gateway/methods/skills.go
@@ -7,6 +7,7 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -55,7 +56,8 @@ func (m *SkillsMethods) handleList(_ context.Context, client *gateway.Client, re
 	}))
 }
 
-func (m *SkillsMethods) handleGet(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *SkillsMethods) handleGet(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Name string `json:"name"`
 	}
@@ -63,13 +65,13 @@ func (m *SkillsMethods) handleGet(_ context.Context, client *gateway.Client, req
 		json.Unmarshal(req.Params, &params)
 	}
 	if params.Name == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name")))
 		return
 	}
 
 	info, ok := m.store.GetSkill(params.Name)
 	if !ok {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "skill not found: "+params.Name))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgNotFound, "skill", params.Name)))
 		return
 	}
 
@@ -100,7 +102,8 @@ type skillUpdater interface {
 	UpdateSkill(id uuid.UUID, updates map[string]interface{}) error
 }
 
-func (m *SkillsMethods) handleUpdate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *SkillsMethods) handleUpdate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	var params struct {
 		Name    string                 `json:"name"`
 		ID      string                 `json:"id"`
@@ -110,14 +113,14 @@ func (m *SkillsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 		json.Unmarshal(req.Params, &params)
 	}
 	if params.Name == "" && params.ID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name or id is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name or id")))
 		return
 	}
 
 	// Check if the store supports updates (PGSkillStore does, FileSkillStore doesn't)
 	updater, ok := m.store.(skillUpdater)
 	if !ok {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "skills.update not supported for file-based skills"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgSkillsUpdateNotSupported)))
 		return
 	}
 
@@ -126,7 +129,7 @@ func (m *SkillsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 	if params.ID != "" {
 		parsed, err := uuid.Parse(params.ID)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid skill ID"))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "skill")))
 			return
 		}
 		skillID = parsed
@@ -135,20 +138,20 @@ func (m *SkillsMethods) handleUpdate(_ context.Context, client *gateway.Client,
 		// For PGSkillStore, the name is the slug
 		info, exists := m.store.GetSkill(params.Name)
 		if !exists {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, "skill not found: "+params.Name))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrNotFound, i18n.T(locale, i18n.MsgNotFound, "skill", params.Name)))
 			return
 		}
 		// Try to parse Path as UUID (PGSkillStore stores DB ID in Path field for managed skills)
 		parsed, err := uuid.Parse(info.Path)
 		if err != nil {
-			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "cannot resolve skill ID for file-based skill"))
+			client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgCannotResolveSkillID)))
 			return
 		}
 		skillID = parsed
 	}
 
 	if params.Updates == nil || len(params.Updates) == 0 {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "updates is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "updates")))
 		return
 	}
 
diff --git a/internal/gateway/methods/teams.go b/internal/gateway/methods/teams.go
index f6c04450..cc3af568 100644
--- a/internal/gateway/methods/teams.go
+++ b/internal/gateway/methods/teams.go
@@ -8,6 +8,7 @@ import (
 	"github.com/nextlevelbuilder/goclaw/internal/agent"
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -50,13 +51,13 @@ func (m *TeamsMethods) Register(router *gateway.MethodRouter) {
 
 // --- List ---
 
-func (m *TeamsMethods) handleList(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleList(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
-	ctx := context.Background()
 	teams, err := m.teamStore.ListTeams(ctx)
 	if err != nil {
 		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, err.Error()))
@@ -79,24 +80,25 @@ type teamsCreateParams struct {
 	Settings    json.RawMessage `json:"settings"`
 }
 
-func (m *TeamsMethods) handleCreate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleCreate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsCreateParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.Name == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "name is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "name")))
 		return
 	}
 	if params.Lead == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "lead is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "lead")))
 		return
 	}
 
@@ -118,8 +120,6 @@ func (m *TeamsMethods) handleCreate(_ context.Context, client *gateway.Client, r
 		memberAgents = append(memberAgents, ag)
 	}
 
-	ctx := context.Background()
-
 	// Create team
 	team := &store.TeamData{
 		Name:        params.Name,
@@ -130,13 +130,13 @@ func (m *TeamsMethods) handleCreate(_ context.Context, client *gateway.Client, r
 		CreatedBy:   client.UserID(),
 	}
 	if err := m.teamStore.CreateTeam(ctx, team); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to create team: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToCreate, "team", err.Error())))
 		return
 	}
 
 	// Add lead as member with lead role
 	if err := m.teamStore.AddMember(ctx, team.ID, leadAgent.ID, store.TeamRoleLead); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to add lead as member: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToCreate, "team lead membership", err.Error())))
 		return
 	}
 
diff --git a/internal/gateway/methods/teams_crud.go b/internal/gateway/methods/teams_crud.go
index 9ff7a09c..5b572641 100644
--- a/internal/gateway/methods/teams_crud.go
+++ b/internal/gateway/methods/teams_crud.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -18,30 +19,30 @@ type teamsGetParams struct {
 	TeamID string `json:"teamId"`
 }
 
-func (m *TeamsMethods) handleGet(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleGet(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsGetParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.TeamID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "teamId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "teamId")))
 		return
 	}
 
 	teamID, err := uuid.Parse(params.TeamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid teamId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "teamId")))
 		return
 	}
 
-	ctx := context.Background()
 	team, err := m.teamStore.GetTeam(ctx, teamID)
 	if err != nil {
 		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, err.Error()))
@@ -66,37 +67,36 @@ type teamsDeleteParams struct {
 	TeamID string `json:"teamId"`
 }
 
-func (m *TeamsMethods) handleDelete(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleDelete(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsDeleteParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.TeamID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "teamId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "teamId")))
 		return
 	}
 
 	teamID, err := uuid.Parse(params.TeamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid teamId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "teamId")))
 		return
 	}
 
-	ctx := context.Background()
-
 	// Fetch team and members before deleting for event + cache invalidation
 	team, _ := m.teamStore.GetTeam(ctx, teamID)
 	members, _ := m.teamStore.ListMembers(ctx, teamID)
 
 	if err := m.teamStore.DeleteTeam(ctx, teamID); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to delete team: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToDelete, "team", err.Error())))
 		return
 	}
 
@@ -127,30 +127,30 @@ type teamsTaskListParams struct {
 	TeamID string `json:"teamId"`
 }
 
-func (m *TeamsMethods) handleTaskList(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleTaskList(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsTaskListParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.TeamID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "teamId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "teamId")))
 		return
 	}
 
 	teamID, err := uuid.Parse(params.TeamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid teamId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "teamId")))
 		return
 	}
 
-	ctx := context.Background()
 	tasks, err := m.teamStore.ListTasks(ctx, teamID, "newest", store.TeamTaskFilterAll, "")
 	if err != nil {
 		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, err.Error()))
@@ -170,35 +170,34 @@ type teamsUpdateParams struct {
 	Settings map[string]interface{} `json:"settings"`
 }
 
-func (m *TeamsMethods) handleUpdate(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleUpdate(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsUpdateParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.TeamID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "teamId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "teamId")))
 		return
 	}
 
 	teamID, err := uuid.Parse(params.TeamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid teamId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "teamId")))
 		return
 	}
 
-	ctx := context.Background()
-
 	// Validate team exists
 	team, err := m.teamStore.GetTeam(ctx, teamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "team not found: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgNotFound, "team", err.Error())))
 		return
 	}
 
@@ -213,14 +212,14 @@ func (m *TeamsMethods) handleUpdate(_ context.Context, client *gateway.Client, r
 	raw, _ := json.Marshal(params.Settings)
 	var access teamAccessSettings
 	if err := json.Unmarshal(raw, &access); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid settings: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidRequest, err.Error())))
 		return
 	}
 	cleaned, _ := json.Marshal(access)
 
 	updates := map[string]any{"settings": json.RawMessage(cleaned)}
 	if err := m.teamStore.UpdateTeam(ctx, teamID, updates); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to update team: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToUpdate, "team", err.Error())))
 		return
 	}
 
@@ -251,30 +250,30 @@ type teamsKnownUsersParams struct {
 	TeamID string `json:"teamId"`
 }
 
-func (m *TeamsMethods) handleKnownUsers(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleKnownUsers(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsKnownUsersParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 
 	if params.TeamID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "teamId is required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "teamId")))
 		return
 	}
 
 	teamID, err := uuid.Parse(params.TeamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid teamId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "teamId")))
 		return
 	}
 
-	ctx := context.Background()
 	users, err := m.teamStore.KnownUserIDs(ctx, teamID, 100)
 	if err != nil {
 		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, err.Error()))
diff --git a/internal/gateway/methods/teams_members.go b/internal/gateway/methods/teams_members.go
index 6d153c45..179aeb78 100644
--- a/internal/gateway/methods/teams_members.go
+++ b/internal/gateway/methods/teams_members.go
@@ -9,6 +9,7 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
 	"github.com/nextlevelbuilder/goclaw/internal/gateway"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -20,34 +21,33 @@ type teamsAddMemberParams struct {
 	Agent  string `json:"agent"` // agent key or UUID
 }
 
-func (m *TeamsMethods) handleAddMember(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleAddMember(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsAddMemberParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 	if params.TeamID == "" || params.Agent == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "teamId and agent are required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "teamId and agent")))
 		return
 	}
 
 	teamID, err := uuid.Parse(params.TeamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid teamId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "teamId")))
 		return
 	}
 
-	ctx := context.Background()
-
 	// Validate team exists
 	team, err := m.teamStore.GetTeam(ctx, teamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "team not found: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgNotFound, "team", err.Error())))
 		return
 	}
 
@@ -60,13 +60,13 @@ func (m *TeamsMethods) handleAddMember(_ context.Context, client *gateway.Client
 
 	// Prevent adding lead again
 	if ag.ID == team.LeadAgentID {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "agent is already the team lead"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgAgentIsTeamLead)))
 		return
 	}
 
 	// Add member
 	if err := m.teamStore.AddMember(ctx, teamID, ag.ID, store.TeamRoleMember); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to add member: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToCreate, "member", err.Error())))
 		return
 	}
 
@@ -106,43 +106,42 @@ type teamsRemoveMemberParams struct {
 	AgentID string `json:"agentId"` // agent UUID
 }
 
-func (m *TeamsMethods) handleRemoveMember(_ context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+func (m *TeamsMethods) handleRemoveMember(ctx context.Context, client *gateway.Client, req *protocol.RequestFrame) {
+	locale := store.LocaleFromContext(ctx)
 	if m.teamStore == nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "teams not configured"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgTeamsNotConfigured)))
 		return
 	}
 
 	var params teamsRemoveMemberParams
 	if err := json.Unmarshal(req.Params, &params); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid params"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidJSON)))
 		return
 	}
 	if params.TeamID == "" || params.AgentID == "" {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "teamId and agentId are required"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgRequired, "teamId and agentId")))
 		return
 	}
 
 	teamID, err := uuid.Parse(params.TeamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid teamId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "teamId")))
 		return
 	}
 	agentID, err := uuid.Parse(params.AgentID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "invalid agentId"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgInvalidID, "agentId")))
 		return
 	}
 
-	ctx := context.Background()
-
 	// Validate team exists and prevent removing the lead
 	team, err := m.teamStore.GetTeam(ctx, teamID)
 	if err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "team not found: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgNotFound, "team", err.Error())))
 		return
 	}
 	if agentID == team.LeadAgentID {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, "cannot remove the team lead"))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInvalidRequest, i18n.T(locale, i18n.MsgCannotRemoveTeamLead)))
 		return
 	}
 
@@ -151,7 +150,7 @@ func (m *TeamsMethods) handleRemoveMember(_ context.Context, client *gateway.Cli
 
 	// Remove member
 	if err := m.teamStore.RemoveMember(ctx, teamID, agentID); err != nil {
-		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, "failed to remove member: "+err.Error()))
+		client.SendResponse(protocol.NewErrorResponse(req.ID, protocol.ErrInternal, i18n.T(locale, i18n.MsgFailedToDelete, "member", err.Error())))
 		return
 	}
 
diff --git a/internal/gateway/router.go b/internal/gateway/router.go
index dfee89a6..3a5b8d3a 100644
--- a/internal/gateway/router.go
+++ b/internal/gateway/router.go
@@ -6,7 +6,9 @@ import (
 	"log/slog"
 	"time"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/permissions"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
 
@@ -38,10 +40,11 @@ func (r *MethodRouter) Handle(ctx context.Context, client *Client, req *protocol
 	handler, ok := r.handlers[req.Method]
 	if !ok {
 		slog.Warn("unknown method", "method", req.Method, "client", client.id)
+		locale := i18n.Normalize(client.locale)
 		client.SendResponse(protocol.NewErrorResponse(
 			req.ID,
 			protocol.ErrInvalidRequest,
-			"unknown method: "+req.Method,
+			i18n.T(locale, i18n.MsgUnknownMethod, req.Method),
 		))
 		return
 	}
@@ -51,16 +54,20 @@ func (r *MethodRouter) Handle(ctx context.Context, client *Client, req *protocol
 		if pe := r.server.policyEngine; pe != nil {
 			if !pe.CanAccess(client.role, req.Method) {
 				slog.Warn("permission denied", "method", req.Method, "role", client.role, "client", client.id)
+				locale := i18n.Normalize(client.locale)
 				client.SendResponse(protocol.NewErrorResponse(
 					req.ID,
 					protocol.ErrUnauthorized,
-					"permission denied: insufficient role for "+req.Method,
+					i18n.T(locale, i18n.MsgPermissionDenied, req.Method),
 				))
 				return
 			}
 		}
 	}
 
+	// Inject locale into context for i18n support
+	ctx = store.WithLocale(ctx, i18n.Normalize(client.locale))
+
 	slog.Debug("handling method", "method", req.Method, "client", client.id, "req_id", req.ID)
 	handler(ctx, client, req)
 }
@@ -81,11 +88,15 @@ func (r *MethodRouter) handleConnect(ctx context.Context, client *Client, req *p
 		Token    string `json:"token"`
 		UserID   string `json:"user_id"`
 		SenderID string `json:"sender_id"` // browser pairing: stored sender ID for reconnect
+		Locale   string `json:"locale"`    // user's preferred locale (en, vi, zh)
 	}
 	if req.Params != nil {
 		json.Unmarshal(req.Params, &params)
 	}
 
+	// Set locale on client (persists across all requests for this connection)
+	client.locale = i18n.Normalize(params.Locale)
+
 	configToken := r.server.cfg.Gateway.Token
 
 	// Path 1: Valid token → admin
diff --git a/internal/http/agents.go b/internal/http/agents.go
index d2b24bf6..cda4991d 100644
--- a/internal/http/agents.go
+++ b/internal/http/agents.go
@@ -11,6 +11,7 @@ import (
 
 	"github.com/nextlevelbuilder/goclaw/internal/bootstrap"
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -68,16 +69,18 @@ func (h *AgentsHandler) authMiddleware(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
-		// Inject user_id into context
+		// Inject user_id and locale into context
 		userID := extractUserID(r)
+		ctx := store.WithLocale(r.Context(), extractLocale(r))
 		if userID != "" {
-			ctx := store.WithUserID(r.Context(), userID)
-			r = r.WithContext(ctx)
+			ctx = store.WithUserID(ctx, userID)
 		}
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -85,7 +88,8 @@ func (h *AgentsHandler) authMiddleware(next http.HandlerFunc) http.HandlerFunc {
 func (h *AgentsHandler) handleList(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
 	if userID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "X-GoClaw-User-Id header required"})
+		locale := store.LocaleFromContext(r.Context())
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgUserIDHeader)})
 		return
 	}
 
@@ -106,25 +110,26 @@ func (h *AgentsHandler) handleList(w http.ResponseWriter, r *http.Request) {
 
 func (h *AgentsHandler) handleCreate(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	if userID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "X-GoClaw-User-Id header required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgUserIDHeader)})
 		return
 	}
 
 	var req store.AgentData
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON: " + err.Error()})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, err.Error())})
 		return
 	}
 
 	if !isValidSlug(req.AgentKey) {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "agent_key must be a valid slug (lowercase letters, numbers, hyphens only)"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "agent_key")})
 		return
 	}
 
 	// Check for duplicate agent_key before creating
 	if existing, _ := h.agents.GetByKey(r.Context(), req.AgentKey); existing != nil {
-		writeJSON(w, http.StatusConflict, map[string]string{"error": "An agent with key \"" + req.AgentKey + "\" already exists"})
+		writeJSON(w, http.StatusConflict, map[string]string{"error": i18n.T(locale, i18n.MsgAlreadyExists, "agent", req.AgentKey)})
 		return
 	}
 
@@ -161,7 +166,7 @@ func (h *AgentsHandler) handleCreate(w http.ResponseWriter, r *http.Request) {
 
 	if err := h.agents.Create(r.Context(), &req); err != nil {
 		if strings.Contains(err.Error(), "duplicate key") || strings.Contains(err.Error(), "23505") {
-			writeJSON(w, http.StatusConflict, map[string]string{"error": "An agent with this key already exists"})
+			writeJSON(w, http.StatusConflict, map[string]string{"error": i18n.T(locale, i18n.MsgAlreadyExists, "agent", req.AgentKey)})
 		} else {
 			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
 		}
@@ -184,6 +189,7 @@ func (h *AgentsHandler) handleCreate(w http.ResponseWriter, r *http.Request) {
 
 func (h *AgentsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	isOwner := h.isOwnerUser(userID)
 
 	id, err := uuid.Parse(r.PathValue("id"))
@@ -191,12 +197,12 @@ func (h *AgentsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
 		// Try by agent_key
 		ag, err2 := h.agents.GetByKey(r.Context(), r.PathValue("id"))
 		if err2 != nil {
-			writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+			writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", r.PathValue("id"))})
 			return
 		}
 		if userID != "" && !isOwner {
 			if ok, _, _ := h.agents.CanAccess(r.Context(), ag.ID, userID); !ok {
-				writeJSON(w, http.StatusForbidden, map[string]string{"error": "no access to this agent"})
+				writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgNoAccess, "agent")})
 				return
 			}
 		}
@@ -206,13 +212,13 @@ func (h *AgentsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
 
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 
 	if userID != "" && !isOwner {
 		if ok, _, _ := h.agents.CanAccess(r.Context(), id, userID); !ok {
-			writeJSON(w, http.StatusForbidden, map[string]string{"error": "no access to this agent"})
+			writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgNoAccess, "agent")})
 			return
 		}
 	}
@@ -222,26 +228,27 @@ func (h *AgentsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
 
 func (h *AgentsHandler) handleUpdate(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	// Only owner can update
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can update agent"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "update agent")})
 		return
 	}
 
 	var updates map[string]any
 	if err := json.NewDecoder(r.Body).Decode(&updates); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON: " + err.Error()})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, err.Error())})
 		return
 	}
 
@@ -277,20 +284,21 @@ func (h *AgentsHandler) handleUpdate(w http.ResponseWriter, r *http.Request) {
 
 func (h *AgentsHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	// Only owner can delete
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can delete agent"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "delete agent")})
 		return
 	}
 
diff --git a/internal/http/agents_instances.go b/internal/http/agents_instances.go
index 7ae5848e..77a96899 100644
--- a/internal/http/agents_instances.go
+++ b/internal/http/agents_instances.go
@@ -8,25 +8,27 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
 // handleListInstances returns all user instances for a predefined agent.
 func (h *AgentsHandler) handleListInstances(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can view instances"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "view instances")})
 		return
 	}
 
@@ -42,24 +44,25 @@ func (h *AgentsHandler) handleListInstances(w http.ResponseWriter, r *http.Reque
 // handleGetInstanceFiles returns user context files for a specific instance.
 func (h *AgentsHandler) handleGetInstanceFiles(w http.ResponseWriter, r *http.Request) {
 	callerID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 	instanceUserID := r.PathValue("userID")
 	if instanceUserID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "missing userID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "userID")})
 		return
 	}
 
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if callerID != "" && ag.OwnerID != callerID && !h.isOwnerUser(callerID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can view instance files"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "view instance files")})
 		return
 	}
 
@@ -75,44 +78,45 @@ func (h *AgentsHandler) handleGetInstanceFiles(w http.ResponseWriter, r *http.Re
 // handleSetInstanceFile updates a user context file for a specific instance.
 func (h *AgentsHandler) handleSetInstanceFile(w http.ResponseWriter, r *http.Request) {
 	callerID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 	instanceUserID := r.PathValue("userID")
 	fileName := r.PathValue("fileName")
 	if instanceUserID == "" || fileName == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "missing userID or fileName"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "userID and fileName")})
 		return
 	}
 
 	// Only USER.md can be edited via this endpoint — other files are managed by the agent itself.
 	if fileName != "USER.md" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "only USER.md can be edited via this endpoint"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "only USER.md can be edited via this endpoint")})
 		return
 	}
 
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if callerID != "" && ag.OwnerID != callerID && !h.isOwnerUser(callerID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can edit instance files"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "edit instance files")})
 		return
 	}
 
 	body, err := io.ReadAll(io.LimitReader(r.Body, 1<<20)) // 1MB limit
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "failed to read body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, err.Error())})
 		return
 	}
 	var payload struct {
 		Content string `json:"content"`
 	}
 	if err := json.Unmarshal(body, &payload); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
@@ -130,41 +134,42 @@ func (h *AgentsHandler) handleSetInstanceFile(w http.ResponseWriter, r *http.Req
 // handleUpdateInstanceMetadata updates metadata for a user instance.
 func (h *AgentsHandler) handleUpdateInstanceMetadata(w http.ResponseWriter, r *http.Request) {
 	callerID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 	instanceUserID := r.PathValue("userID")
 	if instanceUserID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "missing userID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "userID")})
 		return
 	}
 
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if callerID != "" && ag.OwnerID != callerID && !h.isOwnerUser(callerID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can edit instance metadata"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "edit instance metadata")})
 		return
 	}
 
 	body, err := io.ReadAll(io.LimitReader(r.Body, 1<<20))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "failed to read body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, err.Error())})
 		return
 	}
 	var payload struct {
 		Metadata map[string]string `json:"metadata"`
 	}
 	if err := json.Unmarshal(body, &payload); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if len(payload.Metadata) == 0 {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "metadata is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "metadata")})
 		return
 	}
 
diff --git a/internal/http/agents_sharing.go b/internal/http/agents_sharing.go
index 3f6a6aa2..70b513dd 100644
--- a/internal/http/agents_sharing.go
+++ b/internal/http/agents_sharing.go
@@ -6,25 +6,27 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
 func (h *AgentsHandler) handleListShares(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	// Only owner can list shares
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can view shares"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "view shares")})
 		return
 	}
 
@@ -39,20 +41,21 @@ func (h *AgentsHandler) handleListShares(w http.ResponseWriter, r *http.Request)
 
 func (h *AgentsHandler) handleShare(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	// Only owner can share
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can share agent"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "share agent")})
 		return
 	}
 
@@ -61,11 +64,11 @@ func (h *AgentsHandler) handleShare(w http.ResponseWriter, r *http.Request) {
 		Role   string `json:"role"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON: " + err.Error()})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, err.Error())})
 		return
 	}
 	if req.UserID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "user_id is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "user_id")})
 		return
 	}
 	if err := store.ValidateUserID(req.UserID); err != nil {
@@ -86,20 +89,21 @@ func (h *AgentsHandler) handleShare(w http.ResponseWriter, r *http.Request) {
 
 func (h *AgentsHandler) handleRevokeShare(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	// Only owner can revoke shares
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can revoke shares"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "revoke shares")})
 		return
 	}
 
@@ -118,28 +122,29 @@ func (h *AgentsHandler) handleRevokeShare(w http.ResponseWriter, r *http.Request
 
 func (h *AgentsHandler) handleRegenerate(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	// Only owner can regenerate
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can regenerate agent"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "regenerate agent")})
 		return
 	}
 	if ag.Status == store.AgentStatusSummoning {
-		writeJSON(w, http.StatusConflict, map[string]string{"error": "agent is already being summoned"})
+		writeJSON(w, http.StatusConflict, map[string]string{"error": i18n.T(locale, i18n.MsgAlreadySummoning)})
 		return
 	}
 	if h.summoner == nil {
-		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "summoning not available"})
+		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": i18n.T(locale, i18n.MsgSummoningUnavailable)})
 		return
 	}
 
@@ -147,11 +152,11 @@ func (h *AgentsHandler) handleRegenerate(w http.ResponseWriter, r *http.Request)
 		Prompt string `json:"prompt"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON: " + err.Error()})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, err.Error())})
 		return
 	}
 	if req.Prompt == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "prompt is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "prompt")})
 		return
 	}
 
@@ -170,33 +175,34 @@ func (h *AgentsHandler) handleRegenerate(w http.ResponseWriter, r *http.Request)
 // Used when initial summoning failed (e.g. wrong model) and user wants to retry.
 func (h *AgentsHandler) handleResummon(w http.ResponseWriter, r *http.Request) {
 	userID := store.UserIDFromContext(r.Context())
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	ag, err := h.agents.GetByID(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "agent not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "agent", id.String())})
 		return
 	}
 	if userID != "" && ag.OwnerID != userID && !h.isOwnerUser(userID) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "only owner can resummon agent"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgOwnerOnly, "resummon agent")})
 		return
 	}
 	if ag.Status == store.AgentStatusSummoning {
-		writeJSON(w, http.StatusConflict, map[string]string{"error": "agent is already being summoned"})
+		writeJSON(w, http.StatusConflict, map[string]string{"error": i18n.T(locale, i18n.MsgAlreadySummoning)})
 		return
 	}
 	if h.summoner == nil {
-		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": "summoning not available"})
+		writeJSON(w, http.StatusServiceUnavailable, map[string]string{"error": i18n.T(locale, i18n.MsgSummoningUnavailable)})
 		return
 	}
 
 	description := extractDescription(ag.OtherConfig)
 	if description == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "agent has no description to resummon from"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgNoDescription)})
 		return
 	}
 
diff --git a/internal/http/auth.go b/internal/http/auth.go
index 28bee0cd..38df3c5d 100644
--- a/internal/http/auth.go
+++ b/internal/http/auth.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"strings"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -66,3 +67,21 @@ func extractAgentID(r *http.Request, model string) string {
 
 	return "default"
 }
+
+// extractLocale parses the Accept-Language header and returns a supported locale.
+// Falls back to "en" if no supported language is found.
+func extractLocale(r *http.Request) string {
+	accept := r.Header.Get("Accept-Language")
+	if accept == "" {
+		return i18n.DefaultLocale
+	}
+	// Simple parser: take the first language tag before comma or semicolon
+	for _, part := range strings.Split(accept, ",") {
+		tag := strings.TrimSpace(strings.SplitN(part, ";", 2)[0])
+		locale := i18n.Normalize(tag)
+		if locale != i18n.DefaultLocale || strings.HasPrefix(tag, "en") {
+			return locale
+		}
+	}
+	return i18n.DefaultLocale
+}
diff --git a/internal/http/builtin_tools.go b/internal/http/builtin_tools.go
index 59ac5364..0b19fcf1 100644
--- a/internal/http/builtin_tools.go
+++ b/internal/http/builtin_tools.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -34,7 +35,8 @@ func (h *BuiltinToolsHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
@@ -56,22 +58,24 @@ func (h *BuiltinToolsHandler) handleList(w http.ResponseWriter, r *http.Request)
 	result, err := h.store.List(r.Context())
 	if err != nil {
 		slog.Error("builtin_tools.list", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list tools"})
+		locale := extractLocale(r)
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "tools")})
 		return
 	}
 	writeJSON(w, http.StatusOK, map[string]interface{}{"tools": result})
 }
 
 func (h *BuiltinToolsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	name := r.PathValue("name")
 	if name == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "name")})
 		return
 	}
 
 	def, err := h.store.Get(r.Context(), name)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "tool not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "tool", name)})
 		return
 	}
 
@@ -79,15 +83,16 @@ func (h *BuiltinToolsHandler) handleGet(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *BuiltinToolsHandler) handleUpdate(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	name := r.PathValue("name")
 	if name == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "name")})
 		return
 	}
 
 	var updates map[string]interface{}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&updates); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
@@ -101,7 +106,7 @@ func (h *BuiltinToolsHandler) handleUpdate(w http.ResponseWriter, r *http.Reques
 	}
 
 	if len(allowed) == 0 {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "no valid fields to update (only enabled and settings are editable)"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidUpdates)})
 		return
 	}
 
diff --git a/internal/http/channel_instances.go b/internal/http/channel_instances.go
index c532bc0b..3cf712c7 100644
--- a/internal/http/channel_instances.go
+++ b/internal/http/channel_instances.go
@@ -9,6 +9,7 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -47,15 +48,17 @@ func (h *ChannelInstancesHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
 		userID := extractUserID(r)
+		ctx := store.WithLocale(r.Context(), extractLocale(r))
 		if userID != "" {
-			ctx := store.WithUserID(r.Context(), userID)
-			r = r.WithContext(ctx)
+			ctx = store.WithUserID(ctx, userID)
 		}
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -93,7 +96,8 @@ func (h *ChannelInstancesHandler) handleList(w http.ResponseWriter, r *http.Requ
 	instances, err := h.store.ListPaged(r.Context(), opts)
 	if err != nil {
 		slog.Error("channel_instances.list", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list instances"})
+		locale := store.LocaleFromContext(r.Context())
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "instances")})
 		return
 	}
 
@@ -113,6 +117,7 @@ func (h *ChannelInstancesHandler) handleList(w http.ResponseWriter, r *http.Requ
 }
 
 func (h *ChannelInstancesHandler) handleCreate(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	var body struct {
 		Name        string          `json:"name"`
 		DisplayName string          `json:"display_name"`
@@ -123,23 +128,23 @@ func (h *ChannelInstancesHandler) handleCreate(w http.ResponseWriter, r *http.Re
 		Enabled     *bool           `json:"enabled"`
 	}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&body); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if body.Name == "" || body.ChannelType == "" || body.AgentID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name, channel_type, and agent_id are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "name, channel_type, and agent_id")})
 		return
 	}
 
 	if !isValidChannelType(body.ChannelType) {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid channel_type"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidChannelType)})
 		return
 	}
 
 	agentID, err := uuid.Parse(body.AgentID)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent_id"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
@@ -172,15 +177,16 @@ func (h *ChannelInstancesHandler) handleCreate(w http.ResponseWriter, r *http.Re
 }
 
 func (h *ChannelInstancesHandler) handleGet(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid instance ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "instance")})
 		return
 	}
 
 	inst, err := h.store.Get(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "instance not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgInstanceNotFound)})
 		return
 	}
 
@@ -188,15 +194,16 @@ func (h *ChannelInstancesHandler) handleGet(w http.ResponseWriter, r *http.Reque
 }
 
 func (h *ChannelInstancesHandler) handleUpdate(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid instance ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "instance")})
 		return
 	}
 
 	var updates map[string]interface{}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&updates); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
@@ -211,20 +218,21 @@ func (h *ChannelInstancesHandler) handleUpdate(w http.ResponseWriter, r *http.Re
 }
 
 func (h *ChannelInstancesHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid instance ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "instance")})
 		return
 	}
 
 	// Look up instance to check if it's a default (seeded) instance.
 	inst, err := h.store.Get(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "instance not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgInstanceNotFound)})
 		return
 	}
 	if store.IsDefaultChannelInstance(inst.Name) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "cannot delete default channel instance"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgCannotDeleteDefaultInst)})
 		return
 	}
 
@@ -241,18 +249,18 @@ func (h *ChannelInstancesHandler) handleDelete(w http.ResponseWriter, r *http.Re
 // maskInstanceHTTP returns a map with credentials masked for HTTP responses.
 func maskInstanceHTTP(inst store.ChannelInstanceData) map[string]interface{} {
 	result := map[string]interface{}{
-		"id":           inst.ID,
-		"name":         inst.Name,
-		"display_name": inst.DisplayName,
-		"channel_type": inst.ChannelType,
-		"agent_id":     inst.AgentID,
-		"config":       inst.Config,
-		"enabled":      inst.Enabled,
-		"is_default":       store.IsDefaultChannelInstance(inst.Name),
-		"has_credentials":  len(inst.Credentials) > 0,
-		"created_by":       inst.CreatedBy,
-		"created_at":       inst.CreatedAt,
-		"updated_at":       inst.UpdatedAt,
+		"id":              inst.ID,
+		"name":            inst.Name,
+		"display_name":    inst.DisplayName,
+		"channel_type":    inst.ChannelType,
+		"agent_id":        inst.AgentID,
+		"config":          inst.Config,
+		"enabled":         inst.Enabled,
+		"is_default":      store.IsDefaultChannelInstance(inst.Name),
+		"has_credentials": len(inst.Credentials) > 0,
+		"created_by":      inst.CreatedBy,
+		"created_at":      inst.CreatedAt,
+		"updated_at":      inst.UpdatedAt,
 	}
 
 	if len(inst.Credentials) > 0 {
@@ -277,14 +285,15 @@ func maskInstanceHTTP(inst store.ChannelInstanceData) map[string]interface{} {
 
 // resolveAgentID looks up the channel instance and returns its agent_id.
 func (h *ChannelInstancesHandler) resolveAgentID(w http.ResponseWriter, r *http.Request) (uuid.UUID, bool) {
+	locale := store.LocaleFromContext(r.Context())
 	instID, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid instance ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "instance")})
 		return uuid.Nil, false
 	}
 	inst, err := h.store.Get(r.Context(), instID)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "instance not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgInstanceNotFound)})
 		return uuid.Nil, false
 	}
 	return inst.AgentID, true
@@ -298,7 +307,8 @@ func (h *ChannelInstancesHandler) handleWriterGroups(w http.ResponseWriter, r *h
 	groups, err := h.agentStore.ListGroupFileWriterGroups(r.Context(), agentID)
 	if err != nil {
 		slog.Error("channel_instances.writer_groups", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list writer groups"})
+		locale := store.LocaleFromContext(r.Context())
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "writer groups")})
 		return
 	}
 	if groups == nil {
@@ -312,15 +322,16 @@ func (h *ChannelInstancesHandler) handleListWriters(w http.ResponseWriter, r *ht
 	if !ok {
 		return
 	}
+	locale := store.LocaleFromContext(r.Context())
 	groupID := r.URL.Query().Get("group_id")
 	if groupID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "group_id query parameter is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "group_id")})
 		return
 	}
 	writers, err := h.agentStore.ListGroupFileWriters(r.Context(), agentID, groupID)
 	if err != nil {
 		slog.Error("channel_instances.list_writers", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list writers"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "writers")})
 		return
 	}
 	if writers == nil {
@@ -334,6 +345,7 @@ func (h *ChannelInstancesHandler) handleAddWriter(w http.ResponseWriter, r *http
 	if !ok {
 		return
 	}
+	locale := store.LocaleFromContext(r.Context())
 	var body struct {
 		GroupID     string `json:"group_id"`
 		UserID      string `json:"user_id"`
@@ -341,16 +353,16 @@ func (h *ChannelInstancesHandler) handleAddWriter(w http.ResponseWriter, r *http
 		Username    string `json:"username"`
 	}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<16)).Decode(&body); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if body.GroupID == "" || body.UserID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "group_id and user_id are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "group_id and user_id")})
 		return
 	}
 	if err := h.agentStore.AddGroupFileWriter(r.Context(), agentID, body.GroupID, body.UserID, body.DisplayName, body.Username); err != nil {
 		slog.Error("channel_instances.add_writer", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to add writer"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToCreate, "writer", err.Error())})
 		return
 	}
 	writeJSON(w, http.StatusCreated, map[string]string{"status": "added"})
@@ -361,15 +373,16 @@ func (h *ChannelInstancesHandler) handleRemoveWriter(w http.ResponseWriter, r *h
 	if !ok {
 		return
 	}
+	locale := store.LocaleFromContext(r.Context())
 	userID := r.PathValue("userId")
 	groupID := r.URL.Query().Get("group_id")
 	if groupID == "" || userID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "group_id query parameter and userId path parameter are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "group_id and userId")})
 		return
 	}
 	if err := h.agentStore.RemoveGroupFileWriter(r.Context(), agentID, groupID, userID); err != nil {
 		slog.Error("channel_instances.remove_writer", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to remove writer"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToDelete, "writer", err.Error())})
 		return
 	}
 	writeJSON(w, http.StatusOK, map[string]string{"status": "removed"})
diff --git a/internal/http/chat_completions.go b/internal/http/chat_completions.go
index 90db0e8d..15bb8dbc 100644
--- a/internal/http/chat_completions.go
+++ b/internal/http/chat_completions.go
@@ -10,6 +10,7 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/agent"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/sessions"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
@@ -74,14 +75,16 @@ type chatUsage struct {
 }
 
 func (h *ChatCompletionsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
+
 	if r.Method != http.MethodPost {
-		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		http.Error(w, i18n.T(locale, i18n.MsgMethodNotAllowed), http.StatusMethodNotAllowed)
 		return
 	}
 
 	// Auth check (timing-safe comparison)
 	if !tokenMatch(extractBearerToken(r), h.token) {
-		http.Error(w, `{"error":{"message":"Invalid authentication","type":"invalid_request_error"}}`, http.StatusUnauthorized)
+		http.Error(w, fmt.Sprintf(`{"error":{"message":"%s","type":"invalid_request_error"}}`, i18n.T(locale, i18n.MsgInvalidAuth)), http.StatusUnauthorized)
 		return
 	}
 
@@ -93,7 +96,7 @@ func (h *ChatCompletionsHandler) ServeHTTP(w http.ResponseWriter, r *http.Reques
 		}
 		if !h.rateLimiter(key) {
 			w.Header().Set("Retry-After", "60")
-			http.Error(w, `{"error":{"message":"Rate limit exceeded","type":"rate_limit_error"}}`, http.StatusTooManyRequests)
+			http.Error(w, fmt.Sprintf(`{"error":{"message":"%s","type":"rate_limit_error"}}`, i18n.T(locale, i18n.MsgRateLimitExceeded)), http.StatusTooManyRequests)
 			return
 		}
 	}
@@ -104,25 +107,25 @@ func (h *ChatCompletionsHandler) ServeHTTP(w http.ResponseWriter, r *http.Reques
 
 	var req chatCompletionsRequest
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		http.Error(w, fmt.Sprintf(`{"error":{"message":"Invalid JSON: %s"}}`, err), http.StatusBadRequest)
+		http.Error(w, fmt.Sprintf(`{"error":{"message":"%s"}}`, i18n.T(locale, i18n.MsgInvalidRequest, err.Error())), http.StatusBadRequest)
 		return
 	}
 
 	if len(req.Messages) == 0 {
-		http.Error(w, `{"error":{"message":"messages is required"}}`, http.StatusBadRequest)
+		http.Error(w, fmt.Sprintf(`{"error":{"message":"%s"}}`, i18n.T(locale, i18n.MsgMsgsRequired)), http.StatusBadRequest)
 		return
 	}
 
 	agentID := extractAgentID(r, req.Model)
 	userID := extractUserID(r)
 	if h.isManaged && userID == "" {
-		http.Error(w, `{"error":{"message":"X-GoClaw-User-Id header is required in managed mode"}}`, http.StatusBadRequest)
+		http.Error(w, fmt.Sprintf(`{"error":{"message":"%s"}}`, i18n.T(locale, i18n.MsgUserIDHeader)), http.StatusBadRequest)
 		return
 	}
 
 	loop, err := h.agents.Get(agentID)
 	if err != nil {
-		http.Error(w, fmt.Sprintf(`{"error":{"message":"Agent not found: %s"}}`, agentID), http.StatusNotFound)
+		http.Error(w, fmt.Sprintf(`{"error":{"message":"%s"}}`, i18n.T(locale, i18n.MsgNotFound, "agent", agentID)), http.StatusNotFound)
 		return
 	}
 
@@ -135,12 +138,12 @@ func (h *ChatCompletionsHandler) ServeHTTP(w http.ResponseWriter, r *http.Reques
 		}
 	}
 	if lastMessage == "" {
-		http.Error(w, `{"error":{"message":"No user message found"}}`, http.StatusBadRequest)
+		http.Error(w, fmt.Sprintf(`{"error":{"message":"%s"}}`, i18n.T(locale, i18n.MsgNoUserMessage)), http.StatusBadRequest)
 		return
 	}
 
-	// Inject user_id into context for downstream stores/tools
-	ctx := r.Context()
+	// Inject user_id and locale into context for downstream stores/tools
+	ctx := store.WithLocale(r.Context(), extractLocale(r))
 	if userID != "" {
 		ctx = store.WithUserID(ctx, userID)
 	}
@@ -174,7 +177,8 @@ func (h *ChatCompletionsHandler) handleNonStream(w http.ResponseWriter, r *http.
 	})
 
 	if err != nil {
-		http.Error(w, fmt.Sprintf(`{"error":{"message":"Agent error: %s"}}`, err), http.StatusInternalServerError)
+		locale := store.LocaleFromContext(r.Context())
+		http.Error(w, fmt.Sprintf(`{"error":{"message":"%s"}}`, i18n.T(locale, i18n.MsgInternalError, err.Error())), http.StatusInternalServerError)
 		return
 	}
 
@@ -205,7 +209,8 @@ func (h *ChatCompletionsHandler) handleNonStream(w http.ResponseWriter, r *http.
 func (h *ChatCompletionsHandler) handleStream(w http.ResponseWriter, r *http.Request, loop agent.Agent, runID, sessionKey, message, model, userID string) {
 	flusher, ok := w.(http.Flusher)
 	if !ok {
-		http.Error(w, "streaming not supported", http.StatusInternalServerError)
+		locale := store.LocaleFromContext(r.Context())
+		http.Error(w, i18n.T(locale, i18n.MsgStreamingNotSupported), http.StatusInternalServerError)
 		return
 	}
 
diff --git a/internal/http/custom_tools.go b/internal/http/custom_tools.go
index e85088f3..6a28abae 100644
--- a/internal/http/custom_tools.go
+++ b/internal/http/custom_tools.go
@@ -9,6 +9,7 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/internal/tools"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
@@ -40,15 +41,17 @@ func (h *CustomToolsHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
 		userID := extractUserID(r)
+		ctx := store.WithLocale(r.Context(), extractLocale(r))
 		if userID != "" {
-			ctx := store.WithUserID(r.Context(), userID)
-			r = r.WithContext(ctx)
+			ctx = store.WithUserID(ctx, userID)
 		}
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -64,6 +67,7 @@ func (h *CustomToolsHandler) emitCacheInvalidate(key string) {
 }
 
 func (h *CustomToolsHandler) handleList(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	opts := store.CustomToolListOpts{
 		Limit:  50,
 		Offset: 0,
@@ -72,7 +76,7 @@ func (h *CustomToolsHandler) handleList(w http.ResponseWriter, r *http.Request)
 	if v := r.URL.Query().Get("agent_id"); v != "" {
 		id, err := uuid.Parse(v)
 		if err != nil {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent_id"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 			return
 		}
 		opts.AgentID = &id
@@ -94,7 +98,7 @@ func (h *CustomToolsHandler) handleList(w http.ResponseWriter, r *http.Request)
 	result, err := h.store.ListPaged(r.Context(), opts)
 	if err != nil {
 		slog.Error("custom_tools.list", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list tools"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "tools")})
 		return
 	}
 
@@ -109,25 +113,26 @@ func (h *CustomToolsHandler) handleList(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *CustomToolsHandler) handleCreate(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	var def store.CustomToolDef
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&def); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if def.Name == "" || def.Command == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name and command are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "name and command")})
 		return
 	}
 	if !isValidSlug(def.Name) {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name must be a valid slug (lowercase letters, numbers, hyphens only)"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "name")})
 		return
 	}
 
 	// Check name collision with built-in/MCP tools
 	if h.toolsReg != nil {
 		if _, exists := h.toolsReg.Get(def.Name); exists {
-			writeJSON(w, http.StatusConflict, map[string]string{"error": "tool name conflicts with existing built-in or MCP tool"})
+			writeJSON(w, http.StatusConflict, map[string]string{"error": i18n.T(locale, i18n.MsgAlreadyExists, "tool name", def.Name)})
 			return
 		}
 	}
@@ -152,15 +157,16 @@ func (h *CustomToolsHandler) handleCreate(w http.ResponseWriter, r *http.Request
 }
 
 func (h *CustomToolsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid tool ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "tool")})
 		return
 	}
 
 	def, err := h.store.Get(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "tool not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "tool", id.String())})
 		return
 	}
 
@@ -168,21 +174,22 @@ func (h *CustomToolsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *CustomToolsHandler) handleUpdate(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid tool ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "tool")})
 		return
 	}
 
 	var updates map[string]interface{}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&updates); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if name, ok := updates["name"]; ok {
 		if s, _ := name.(string); !isValidSlug(s) {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name must be a valid slug (lowercase letters, numbers, hyphens only)"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "name")})
 			return
 		}
 	}
@@ -198,9 +205,10 @@ func (h *CustomToolsHandler) handleUpdate(w http.ResponseWriter, r *http.Request
 }
 
 func (h *CustomToolsHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid tool ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "tool")})
 		return
 	}
 
diff --git a/internal/http/delegations.go b/internal/http/delegations.go
index bea5d873..49560dc2 100644
--- a/internal/http/delegations.go
+++ b/internal/http/delegations.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -28,10 +29,14 @@ func (h *DelegationsHandler) authMiddleware(next http.HandlerFunc) http.HandlerF
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
+		locale := extractLocale(r)
+		ctx := store.WithLocale(r.Context(), locale)
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -87,10 +92,11 @@ func (h *DelegationsHandler) handleList(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *DelegationsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	idStr := r.PathValue("id")
 	id, err := uuid.Parse(idStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid id"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "delegation")})
 		return
 	}
 
diff --git a/internal/http/files.go b/internal/http/files.go
index 32ceadb4..c88ea077 100644
--- a/internal/http/files.go
+++ b/internal/http/files.go
@@ -7,6 +7,8 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 )
 
 // FilesHandler serves files over HTTP with Bearer token auth.
@@ -34,7 +36,8 @@ func (h *FilesHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 				provided = r.URL.Query().Get("token")
 			}
 			if provided != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
@@ -43,16 +46,17 @@ func (h *FilesHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 }
 
 func (h *FilesHandler) handleServe(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	urlPath := r.PathValue("path")
 	if urlPath == "" {
-		http.Error(w, "path is required", http.StatusBadRequest)
+		http.Error(w, i18n.T(locale, i18n.MsgRequired, "path"), http.StatusBadRequest)
 		return
 	}
 
 	// Prevent path traversal
 	if strings.Contains(urlPath, "..") {
 		slog.Warn("security.files_traversal", "path", urlPath)
-		http.Error(w, "invalid path", http.StatusBadRequest)
+		http.Error(w, i18n.T(locale, i18n.MsgInvalidPath), http.StatusBadRequest)
 		return
 	}
 
diff --git a/internal/http/knowledge_graph_handlers.go b/internal/http/knowledge_graph_handlers.go
index 4b388711..6d3e6aaa 100644
--- a/internal/http/knowledge_graph_handlers.go
+++ b/internal/http/knowledge_graph_handlers.go
@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"strconv"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -53,13 +54,14 @@ func (h *KnowledgeGraphHandler) handleListEntities(w http.ResponseWriter, r *htt
 }
 
 func (h *KnowledgeGraphHandler) handleGetEntity(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 	entityID := r.PathValue("entityID")
 	userID := r.URL.Query().Get("user_id")
 
 	entity, err := h.store.GetEntity(r.Context(), agentID, userID, entityID)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "entity not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "entity", entityID)})
 		return
 	}
 
@@ -78,17 +80,18 @@ func (h *KnowledgeGraphHandler) handleGetEntity(w http.ResponseWriter, r *http.R
 }
 
 func (h *KnowledgeGraphHandler) handleUpsertEntity(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 
 	var entity store.Entity
 	if err := json.NewDecoder(r.Body).Decode(&entity); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	entity.AgentID = agentID
 
 	if entity.ExternalID == "" || entity.Name == "" || entity.EntityType == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "external_id, name, and entity_type are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgEntityFieldsRequired)})
 		return
 	}
 	if entity.Confidence <= 0 {
@@ -117,6 +120,7 @@ func (h *KnowledgeGraphHandler) handleDeleteEntity(w http.ResponseWriter, r *htt
 }
 
 func (h *KnowledgeGraphHandler) handleTraverse(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 
 	var body struct {
@@ -125,11 +129,11 @@ func (h *KnowledgeGraphHandler) handleTraverse(w http.ResponseWriter, r *http.Re
 		MaxDepth int    `json:"max_depth"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if body.EntityID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "entity_id is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgEntityIDRequired)})
 		return
 	}
 	if body.MaxDepth <= 0 {
@@ -152,6 +156,7 @@ func (h *KnowledgeGraphHandler) handleTraverse(w http.ResponseWriter, r *http.Re
 }
 
 func (h *KnowledgeGraphHandler) handleExtract(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 
 	var body struct {
@@ -162,21 +167,21 @@ func (h *KnowledgeGraphHandler) handleExtract(w http.ResponseWriter, r *http.Req
 		MinConf  float64 `json:"min_confidence"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if body.Text == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "text is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgTextRequired)})
 		return
 	}
 	if body.Provider == "" || body.Model == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "provider and model are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgProviderModelRequired)})
 		return
 	}
 
 	extractor := h.NewExtractor(body.Provider, body.Model, body.MinConf)
 	if extractor == nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid provider or model"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidProviderOrModel)})
 		return
 	}
 
diff --git a/internal/http/mcp.go b/internal/http/mcp.go
index 82c3aac2..71f67a58 100644
--- a/internal/http/mcp.go
+++ b/internal/http/mcp.go
@@ -8,6 +8,7 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
 )
@@ -75,15 +76,17 @@ func (h *MCPHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
 		userID := extractUserID(r)
+		ctx := store.WithLocale(r.Context(), extractLocale(r))
 		if userID != "" {
-			ctx := store.WithUserID(r.Context(), userID)
-			r = r.WithContext(ctx)
+			ctx = store.WithUserID(ctx, userID)
 		}
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -94,25 +97,27 @@ func (h *MCPHandler) handleListServers(w http.ResponseWriter, r *http.Request) {
 	servers, err := h.store.ListServers(r.Context())
 	if err != nil {
 		slog.Error("mcp.list_servers", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list servers"})
+		locale := store.LocaleFromContext(r.Context())
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "servers")})
 		return
 	}
 	writeJSON(w, http.StatusOK, map[string]interface{}{"servers": servers})
 }
 
 func (h *MCPHandler) handleCreateServer(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	var srv store.MCPServerData
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&srv); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if srv.Name == "" || srv.Transport == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name and transport are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "name and transport")})
 		return
 	}
 	if !isValidSlug(srv.Name) {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name must be a valid slug (lowercase letters, numbers, hyphens only)"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "name")})
 		return
 	}
 
@@ -132,15 +137,16 @@ func (h *MCPHandler) handleCreateServer(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *MCPHandler) handleGetServer(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
 	srv, err := h.store.GetServer(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "server not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "server", id.String())})
 		return
 	}
 
@@ -148,21 +154,22 @@ func (h *MCPHandler) handleGetServer(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *MCPHandler) handleUpdateServer(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
 	var updates map[string]interface{}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&updates); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if name, ok := updates["name"]; ok {
 		if s, _ := name.(string); !isValidSlug(s) {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name must be a valid slug (lowercase letters, numbers, hyphens only)"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "name")})
 			return
 		}
 	}
@@ -178,9 +185,10 @@ func (h *MCPHandler) handleUpdateServer(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *MCPHandler) handleDeleteServer(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
@@ -193,4 +201,3 @@ func (h *MCPHandler) handleDeleteServer(w http.ResponseWriter, r *http.Request)
 	h.emitCacheInvalidate()
 	writeJSON(w, http.StatusOK, map[string]string{"status": "deleted"})
 }
-
diff --git a/internal/http/mcp_grants.go b/internal/http/mcp_grants.go
index d8409d80..bf492d94 100644
--- a/internal/http/mcp_grants.go
+++ b/internal/http/mcp_grants.go
@@ -7,13 +7,15 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
 func (h *MCPHandler) handleGrantAgent(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	serverID, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
@@ -23,13 +25,13 @@ func (h *MCPHandler) handleGrantAgent(w http.ResponseWriter, r *http.Request) {
 		ToolDeny  json.RawMessage `json:"tool_deny,omitempty"`
 	}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	agentID, err := uuid.Parse(req.AgentID)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent_id"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
@@ -53,15 +55,16 @@ func (h *MCPHandler) handleGrantAgent(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *MCPHandler) handleRevokeAgent(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	serverID, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
 	agentID, err := uuid.Parse(r.PathValue("agentID"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
@@ -76,9 +79,10 @@ func (h *MCPHandler) handleRevokeAgent(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *MCPHandler) handleListAgentGrants(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	agentID, err := uuid.Parse(r.PathValue("agentID"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
@@ -93,16 +97,17 @@ func (h *MCPHandler) handleListAgentGrants(w http.ResponseWriter, r *http.Reques
 }
 
 func (h *MCPHandler) handleListServerGrants(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	serverID, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
 	grants, err := h.store.ListServerGrants(r.Context(), serverID)
 	if err != nil {
 		slog.Error("mcp.list_server_grants", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list grants"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "grants")})
 		return
 	}
 
@@ -110,9 +115,10 @@ func (h *MCPHandler) handleListServerGrants(w http.ResponseWriter, r *http.Reque
 }
 
 func (h *MCPHandler) handleGrantUser(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	serverID, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
@@ -122,12 +128,12 @@ func (h *MCPHandler) handleGrantUser(w http.ResponseWriter, r *http.Request) {
 		ToolDeny  json.RawMessage `json:"tool_deny,omitempty"`
 	}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if req.UserID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "user_id is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "user_id")})
 		return
 	}
 	if err := store.ValidateUserID(req.UserID); err != nil {
@@ -155,9 +161,10 @@ func (h *MCPHandler) handleGrantUser(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *MCPHandler) handleRevokeUser(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	serverID, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
diff --git a/internal/http/mcp_requests.go b/internal/http/mcp_requests.go
index 4a193258..e0eb7e29 100644
--- a/internal/http/mcp_requests.go
+++ b/internal/http/mcp_requests.go
@@ -7,22 +7,24 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
 func (h *MCPHandler) handleCreateRequest(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	var req store.MCPAccessRequest
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if req.ServerID == uuid.Nil || req.Scope == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "server_id and scope are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "server_id and scope")})
 		return
 	}
 	if req.Scope != "agent" && req.Scope != "user" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "scope must be 'agent' or 'user'"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "scope must be 'agent' or 'user'")})
 		return
 	}
 
@@ -50,9 +52,10 @@ func (h *MCPHandler) handleListPendingRequests(w http.ResponseWriter, r *http.Re
 }
 
 func (h *MCPHandler) handleReviewRequest(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	requestID, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "request")})
 		return
 	}
 
@@ -61,7 +64,7 @@ func (h *MCPHandler) handleReviewRequest(w http.ResponseWriter, r *http.Request)
 		Note     string `json:"note,omitempty"`
 	}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
diff --git a/internal/http/mcp_tools.go b/internal/http/mcp_tools.go
index a0202f27..e9f92f21 100644
--- a/internal/http/mcp_tools.go
+++ b/internal/http/mcp_tools.go
@@ -7,11 +7,14 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 	mcpbridge "github.com/nextlevelbuilder/goclaw/internal/mcp"
 )
 
 // handleTestConnection tests an MCP server connection without saving it.
 func (h *MCPHandler) handleTestConnection(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	var req struct {
 		Transport string            `json:"transport"`
 		Command   string            `json:"command"`
@@ -21,11 +24,11 @@ func (h *MCPHandler) handleTestConnection(w http.ResponseWriter, r *http.Request
 		Env       map[string]string `json:"env"`
 	}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if req.Transport == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "transport is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "transport")})
 		return
 	}
 
@@ -46,15 +49,16 @@ func (h *MCPHandler) handleTestConnection(w http.ResponseWriter, r *http.Request
 
 // handleListServerTools lists tools for a specific MCP server.
 func (h *MCPHandler) handleListServerTools(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid server ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "server")})
 		return
 	}
 
 	srv, err := h.store.GetServer(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "server not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "server", id.String())})
 		return
 	}
 
diff --git a/internal/http/media_serve.go b/internal/http/media_serve.go
index 74ee3d61..1cade70a 100644
--- a/internal/http/media_serve.go
+++ b/internal/http/media_serve.go
@@ -7,6 +7,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/media"
 )
 
@@ -34,7 +35,8 @@ func (h *MediaServeHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 				provided = r.URL.Query().Get("token")
 			}
 			if provided != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
@@ -43,9 +45,10 @@ func (h *MediaServeHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 }
 
 func (h *MediaServeHandler) handleServe(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	id := r.PathValue("id")
 	if id == "" || strings.Contains(id, "..") || strings.Contains(id, "/") {
-		http.Error(w, "invalid media id", http.StatusBadRequest)
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "invalid media id")})
 		return
 	}
 
diff --git a/internal/http/media_upload.go b/internal/http/media_upload.go
index 3141e876..32483dd8 100644
--- a/internal/http/media_upload.go
+++ b/internal/http/media_upload.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/nextlevelbuilder/goclaw/internal/channels/media"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 )
 
 const (
@@ -37,7 +38,8 @@ func (h *MediaUploadHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 		if h.token != "" {
 			provided := extractBearerToken(r)
 			if provided != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
@@ -46,16 +48,17 @@ func (h *MediaUploadHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 }
 
 func (h *MediaUploadHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	r.Body = http.MaxBytesReader(w, r.Body, maxUploadSize)
 
 	if err := r.ParseMultipartForm(maxUploadSize); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "file too large or invalid multipart form"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgFileTooLarge)})
 		return
 	}
 
 	file, header, err := r.FormFile("file")
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "missing 'file' field"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgMissingFileField)})
 		return
 	}
 	defer file.Close()
@@ -63,7 +66,7 @@ func (h *MediaUploadHandler) handleUpload(w http.ResponseWriter, r *http.Request
 	// Sanitize filename: strip path, prevent traversal.
 	origName := filepath.Base(header.Filename)
 	if origName == "." || origName == "/" || strings.Contains(origName, "..") {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid filename"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidFilename)})
 		return
 	}
 
@@ -78,14 +81,14 @@ func (h *MediaUploadHandler) handleUpload(w http.ResponseWriter, r *http.Request
 
 	out, err := os.Create(tmpPath)
 	if err != nil {
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to create temp file"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgInternalError, "failed to create temp file")})
 		return
 	}
 	defer out.Close()
 
 	if _, err := io.Copy(out, file); err != nil {
 		os.Remove(tmpPath)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to save file"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgInternalError, "failed to save file")})
 		return
 	}
 
diff --git a/internal/http/memory.go b/internal/http/memory.go
index 79fdfd10..3f5a88d4 100644
--- a/internal/http/memory.go
+++ b/internal/http/memory.go
@@ -3,6 +3,7 @@ package http
 import (
 	"net/http"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -34,7 +35,8 @@ func (h *MemoryHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
diff --git a/internal/http/memory_handlers.go b/internal/http/memory_handlers.go
index 2b6d63ed..ee2c287a 100644
--- a/internal/http/memory_handlers.go
+++ b/internal/http/memory_handlers.go
@@ -5,6 +5,7 @@ import (
 	"log/slog"
 	"net/http"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -44,6 +45,7 @@ func (h *MemoryHandler) handleListDocuments(w http.ResponseWriter, r *http.Reque
 }
 
 func (h *MemoryHandler) handleGetDocument(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 	path := r.PathValue("path")
 	userID := r.URL.Query().Get("user_id")
@@ -51,13 +53,14 @@ func (h *MemoryHandler) handleGetDocument(w http.ResponseWriter, r *http.Request
 	detail, err := h.store.GetDocumentDetail(r.Context(), agentID, userID, path)
 	if err != nil {
 		slog.Warn("memory.get_document failed", "error", err, "path", path)
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "document not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "document", path)})
 		return
 	}
 	writeJSON(w, http.StatusOK, detail)
 }
 
 func (h *MemoryHandler) handlePutDocument(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 	path := r.PathValue("path")
 
@@ -66,7 +69,7 @@ func (h *MemoryHandler) handlePutDocument(w http.ResponseWriter, r *http.Request
 		UserID  string `json:"user_id"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
@@ -92,12 +95,13 @@ func (h *MemoryHandler) handleDeleteDocument(w http.ResponseWriter, r *http.Requ
 }
 
 func (h *MemoryHandler) handleListChunks(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 	path := r.URL.Query().Get("path")
 	userID := r.URL.Query().Get("user_id")
 
 	if path == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "path query parameter required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "path")})
 		return
 	}
 
@@ -114,6 +118,7 @@ func (h *MemoryHandler) handleListChunks(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *MemoryHandler) handleIndexDocument(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 
 	var body struct {
@@ -121,11 +126,11 @@ func (h *MemoryHandler) handleIndexDocument(w http.ResponseWriter, r *http.Reque
 		UserID string `json:"user_id"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if body.Path == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "path is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "path")})
 		return
 	}
 
@@ -154,6 +159,7 @@ func (h *MemoryHandler) handleIndexAll(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *MemoryHandler) handleSearch(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	agentID := r.PathValue("agentID")
 
 	var body struct {
@@ -163,11 +169,11 @@ func (h *MemoryHandler) handleSearch(w http.ResponseWriter, r *http.Request) {
 		MinScore   float64 `json:"min_score"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid request body"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if body.Query == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "query is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "query")})
 		return
 	}
 
diff --git a/internal/http/oauth.go b/internal/http/oauth.go
index e160d4cb..fa13d5e8 100644
--- a/internal/http/oauth.go
+++ b/internal/http/oauth.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/oauth"
 	"github.com/nextlevelbuilder/goclaw/internal/providers"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
@@ -47,7 +48,8 @@ func (h *OAuthHandler) RegisterRoutes(mux *http.ServeMux) {
 func (h *OAuthHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if !tokenMatch(extractBearerToken(r), h.token) {
-			writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+			locale := extractLocale(r)
+			writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 			return
 		}
 		next(w, r)
@@ -80,6 +82,7 @@ func (h *OAuthHandler) handleStatus(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *OAuthHandler) handleStart(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
@@ -102,7 +105,7 @@ func (h *OAuthHandler) handleStart(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		slog.Error("oauth.start", "error", err)
 		writeJSON(w, http.StatusInternalServerError, map[string]string{
-			"error": "failed to start OAuth flow (is port 1455 available?)",
+			"error": i18n.T(locale, i18n.MsgInternalError, "failed to start OAuth flow (is port 1455 available?)"),
 		})
 		return
 	}
@@ -142,11 +145,12 @@ func (h *OAuthHandler) waitForCallback(pending *oauth.PendingLogin) {
 }
 
 func (h *OAuthHandler) handleManualCallback(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	var body struct {
 		RedirectURL string `json:"redirect_url"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&body); err != nil || body.RedirectURL == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "redirect_url is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "redirect_url")})
 		return
 	}
 
@@ -155,7 +159,7 @@ func (h *OAuthHandler) handleManualCallback(w http.ResponseWriter, r *http.Reque
 	h.mu.Unlock()
 
 	if pending == nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "no pending OAuth flow"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgNoPendingOAuth)})
 		return
 	}
 
@@ -177,7 +181,7 @@ func (h *OAuthHandler) handleManualCallback(w http.ResponseWriter, r *http.Reque
 	providerID, err := h.saveAndRegister(r.Context(), tokenResp)
 	if err != nil {
 		slog.Error("oauth.save_token", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to save token"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToSaveToken)})
 		return
 	}
 
diff --git a/internal/http/pending_messages.go b/internal/http/pending_messages.go
index e9ab803b..17aeb9de 100644
--- a/internal/http/pending_messages.go
+++ b/internal/http/pending_messages.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"net/http"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -28,10 +29,14 @@ func (h *PendingMessagesHandler) authMiddleware(next http.HandlerFunc) http.Hand
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
+		locale := extractLocale(r)
+		ctx := store.WithLocale(r.Context(), locale)
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -58,10 +63,11 @@ func (h *PendingMessagesHandler) handleListGroups(w http.ResponseWriter, r *http
 
 // GET /v1/pending-messages/messages?channel=X&key=Y — list messages for a group
 func (h *PendingMessagesHandler) handleListMessages(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	channel := r.URL.Query().Get("channel")
 	key := r.URL.Query().Get("key")
 	if channel == "" || key == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "channel and key are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgChannelKeyReq)})
 		return
 	}
 
@@ -75,10 +81,11 @@ func (h *PendingMessagesHandler) handleListMessages(w http.ResponseWriter, r *ht
 
 // DELETE /v1/pending-messages?channel=X&key=Y — clear a group
 func (h *PendingMessagesHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	channel := r.URL.Query().Get("channel")
 	key := r.URL.Query().Get("key")
 	if channel == "" || key == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "channel and key are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgChannelKeyReq)})
 		return
 	}
 
@@ -96,13 +103,14 @@ type compactRequest struct {
 
 // POST /v1/pending-messages/compact — MVP: clear group and return success
 func (h *PendingMessagesHandler) handleCompact(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	var req compactRequest
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if req.ChannelName == "" || req.HistoryKey == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "channel_name and history_key are required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "channel_name and history_key")})
 		return
 	}
 
diff --git a/internal/http/provider_models.go b/internal/http/provider_models.go
index 81e88533..55e2c8b7 100644
--- a/internal/http/provider_models.go
+++ b/internal/http/provider_models.go
@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/google/uuid"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -25,15 +26,16 @@ type ModelInfo struct {
 //
 //	GET /v1/providers/{id}/models
 func (h *ProvidersHandler) handleListProviderModels(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid provider ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "provider")})
 		return
 	}
 
 	p, err := h.store.GetProvider(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "provider not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "provider", id.String())})
 		return
 	}
 
@@ -44,7 +46,7 @@ func (h *ProvidersHandler) handleListProviderModels(w http.ResponseWriter, r *ht
 	}
 
 	if p.APIKey == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "provider has no API key configured"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "API key")})
 		return
 	}
 
diff --git a/internal/http/provider_verify.go b/internal/http/provider_verify.go
index d91d2911..7b3cb4af 100644
--- a/internal/http/provider_verify.go
+++ b/internal/http/provider_verify.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/google/uuid"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/providers"
 )
 
@@ -17,9 +18,10 @@ import (
 //	Body: {"model": "anthropic/claude-sonnet-4"}
 //	Response: {"valid": true} or {"valid": false, "error": "..."}
 func (h *ProvidersHandler) handleVerifyProvider(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid provider ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "provider")})
 		return
 	}
 
@@ -27,18 +29,18 @@ func (h *ProvidersHandler) handleVerifyProvider(w http.ResponseWriter, r *http.R
 		Model string `json:"model"`
 	}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<16)).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if req.Model == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "model is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "model")})
 		return
 	}
 
 	// Look up provider record from DB to get the provider name
 	p, err := h.store.GetProvider(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "provider not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "provider", id.String())})
 		return
 	}
 
diff --git a/internal/http/providers.go b/internal/http/providers.go
index 809d9b5a..20d7b005 100644
--- a/internal/http/providers.go
+++ b/internal/http/providers.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/oauth"
 	"github.com/nextlevelbuilder/goclaw/internal/providers"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
@@ -58,7 +59,8 @@ func (h *ProvidersHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
@@ -128,7 +130,8 @@ func (h *ProvidersHandler) handleListProviders(w http.ResponseWriter, r *http.Re
 	providers, err := h.store.ListProviders(r.Context())
 	if err != nil {
 		slog.Error("providers.list", "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list providers"})
+		locale := extractLocale(r)
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "providers")})
 		return
 	}
 
@@ -140,22 +143,23 @@ func (h *ProvidersHandler) handleListProviders(w http.ResponseWriter, r *http.Re
 }
 
 func (h *ProvidersHandler) handleCreateProvider(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	var p store.LLMProviderData
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&p); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if p.Name == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "name")})
 		return
 	}
 	if !isValidSlug(p.Name) {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name must be a valid slug (lowercase letters, numbers, hyphens only)"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "name")})
 		return
 	}
 	if !store.ValidProviderTypes[p.ProviderType] {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "unsupported provider_type"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "unsupported provider_type")})
 		return
 	}
 
@@ -169,7 +173,7 @@ func (h *ProvidersHandler) handleCreateProvider(w http.ResponseWriter, r *http.R
 		for _, ep := range existing {
 			if ep.ProviderType == store.ProviderClaudeCLI {
 				writeJSON(w, http.StatusConflict, map[string]string{
-					"error": "A Claude CLI provider already exists. Only one is allowed per instance.",
+					"error": i18n.T(locale, i18n.MsgAlreadyExists, "Claude CLI provider", "only one is allowed per instance"),
 				})
 				return
 			}
@@ -190,15 +194,16 @@ func (h *ProvidersHandler) handleCreateProvider(w http.ResponseWriter, r *http.R
 }
 
 func (h *ProvidersHandler) handleGetProvider(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid provider ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "provider")})
 		return
 	}
 
 	p, err := h.store.GetProvider(r.Context(), id)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "provider not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "provider", id.String())})
 		return
 	}
 
@@ -207,22 +212,23 @@ func (h *ProvidersHandler) handleGetProvider(w http.ResponseWriter, r *http.Requ
 }
 
 func (h *ProvidersHandler) handleUpdateProvider(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid provider ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "provider")})
 		return
 	}
 
 	var updates map[string]interface{}
 	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<20)).Decode(&updates); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	// Validate name if being updated
 	if name, ok := updates["name"]; ok {
 		if s, _ := name.(string); !isValidSlug(s) {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "name must be a valid slug"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "name")})
 			return
 		}
 	}
@@ -233,7 +239,7 @@ func (h *ProvidersHandler) handleUpdateProvider(w http.ResponseWriter, r *http.R
 	// silently deleting it would hide the error from the end user.
 	if pt, ok := updates["provider_type"]; ok {
 		if s, _ := pt.(string); !store.ValidProviderTypes[s] {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "unsupported provider_type"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "unsupported provider_type")})
 			return
 		}
 	}
@@ -282,9 +288,10 @@ func (h *ProvidersHandler) handleUpdateProvider(w http.ResponseWriter, r *http.R
 }
 
 func (h *ProvidersHandler) handleDeleteProvider(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid provider ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "provider")})
 		return
 	}
 
diff --git a/internal/http/skills.go b/internal/http/skills.go
index aef302ce..28da40fc 100644
--- a/internal/http/skills.go
+++ b/internal/http/skills.go
@@ -8,6 +8,7 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/internal/store/pg"
 	"github.com/nextlevelbuilder/goclaw/pkg/protocol"
@@ -62,15 +63,17 @@ func (h *SkillsHandler) authMiddleware(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
 		userID := extractUserID(r)
+		ctx := store.WithLocale(r.Context(), extractLocale(r))
 		if userID != "" {
-			ctx := store.WithUserID(r.Context(), userID)
-			r = r.WithContext(ctx)
+			ctx = store.WithUserID(ctx, userID)
 		}
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -81,26 +84,28 @@ func (h *SkillsHandler) handleList(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *SkillsHandler) handleGet(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id := r.PathValue("id")
 	skill, ok := h.skills.GetSkill(id)
 	if !ok {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "skill not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "skill", id)})
 		return
 	}
 	writeJSON(w, http.StatusOK, skill)
 }
 
 func (h *SkillsHandler) handleUpdate(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	idStr := r.PathValue("id")
 	id, err := uuid.Parse(idStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
 	var updates map[string]interface{}
 	if err := json.NewDecoder(r.Body).Decode(&updates); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	// Prevent changing sensitive fields
@@ -118,10 +123,11 @@ func (h *SkillsHandler) handleUpdate(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *SkillsHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	idStr := r.PathValue("id")
 	id, err := uuid.Parse(idStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
@@ -133,4 +139,3 @@ func (h *SkillsHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
 	h.skills.BumpVersion()
 	writeJSON(w, http.StatusOK, map[string]string{"ok": "true"})
 }
-
diff --git a/internal/http/skills_grants.go b/internal/http/skills_grants.go
index 76bc4082..63bbd8d8 100644
--- a/internal/http/skills_grants.go
+++ b/internal/http/skills_grants.go
@@ -12,21 +12,23 @@ import (
 	"github.com/google/uuid"
 
 	"github.com/nextlevelbuilder/goclaw/internal/bus"
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
 func (h *SkillsHandler) handleListAgentSkills(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	agentIDStr := r.PathValue("agentID")
 	agentID, err := uuid.Parse(agentIDStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
 	skills, err := h.skills.ListWithGrantStatus(r.Context(), agentID)
 	if err != nil {
 		slog.Error("failed to list skills with grant status", "agent_id", agentID, "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to list skills"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToList, "skills")})
 		return
 	}
 
@@ -34,11 +36,12 @@ func (h *SkillsHandler) handleListAgentSkills(w http.ResponseWriter, r *http.Req
 }
 
 func (h *SkillsHandler) handleGrantAgent(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	userID := store.UserIDFromContext(r.Context())
 	idStr := r.PathValue("id")
 	skillID, err := uuid.Parse(idStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
@@ -47,13 +50,13 @@ func (h *SkillsHandler) handleGrantAgent(w http.ResponseWriter, r *http.Request)
 		Version int    `json:"version"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	agentID, err := uuid.Parse(req.AgentID)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent_id"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
@@ -72,17 +75,18 @@ func (h *SkillsHandler) handleGrantAgent(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *SkillsHandler) handleRevokeAgent(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	idStr := r.PathValue("id")
 	skillID, err := uuid.Parse(idStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
 	agentIDStr := r.PathValue("agentID")
 	agentID, err := uuid.Parse(agentIDStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid agent ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "agent")})
 		return
 	}
 
@@ -97,11 +101,12 @@ func (h *SkillsHandler) handleRevokeAgent(w http.ResponseWriter, r *http.Request
 }
 
 func (h *SkillsHandler) handleGrantUser(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	userID := store.UserIDFromContext(r.Context())
 	idStr := r.PathValue("id")
 	skillID, err := uuid.Parse(idStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
@@ -109,11 +114,11 @@ func (h *SkillsHandler) handleGrantUser(w http.ResponseWriter, r *http.Request)
 		UserID string `json:"user_id"`
 	}
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid JSON"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 	if req.UserID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "user_id is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "user_id")})
 		return
 	}
 	if err := store.ValidateUserID(req.UserID); err != nil {
@@ -132,10 +137,11 @@ func (h *SkillsHandler) handleGrantUser(w http.ResponseWriter, r *http.Request)
 }
 
 func (h *SkillsHandler) handleRevokeUser(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	idStr := r.PathValue("id")
 	skillID, err := uuid.Parse(idStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
diff --git a/internal/http/skills_upload.go b/internal/http/skills_upload.go
index e87a2fe9..b7a918c7 100644
--- a/internal/http/skills_upload.go
+++ b/internal/http/skills_upload.go
@@ -11,15 +11,17 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/internal/store/pg"
 )
 
 // handleUpload processes a ZIP file upload containing a skill (must have SKILL.md at root).
 func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	userID := store.UserIDFromContext(r.Context())
 	if userID == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "X-GoClaw-User-Id header required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgUserIDHeader)})
 		return
 	}
 
@@ -27,7 +29,7 @@ func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
 
 	file, header, err := r.FormFile("file")
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "file is required: " + err.Error()})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "file is required: "+err.Error())})
 		return
 	}
 	defer file.Close()
@@ -35,7 +37,7 @@ func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
 	// Save to temp file for zip processing
 	tmp, err := os.CreateTemp("", "skill-upload-*.zip")
 	if err != nil {
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to create temp file"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgInternalError, "failed to create temp file")})
 		return
 	}
 	defer os.Remove(tmp.Name())
@@ -44,7 +46,7 @@ func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
 	hasher := sha256.New()
 	size, err := io.Copy(io.MultiWriter(tmp, hasher), file)
 	if err != nil {
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to save upload"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgInternalError, "failed to save upload")})
 		return
 	}
 	fileHash := fmt.Sprintf("%x", hasher.Sum(nil))
@@ -52,7 +54,7 @@ func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
 	// Open as zip
 	zr, err := zip.OpenReader(tmp.Name())
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid ZIP file"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "invalid ZIP file")})
 		return
 	}
 	defer zr.Close()
@@ -77,27 +79,27 @@ func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 	if skillMD == nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "ZIP must contain SKILL.md at root (or inside a single top-level directory)"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "ZIP must contain SKILL.md at root (or inside a single top-level directory)")})
 		return
 	}
 
 	// Read and parse SKILL.md frontmatter
 	skillContent, err := readZipFile(skillMD)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "failed to read SKILL.md"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidRequest, "failed to read SKILL.md")})
 		return
 	}
 
 	name, description, slug, frontmatter := parseSkillFrontmatter(skillContent)
 	if name == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "SKILL.md must have a name in frontmatter"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "name in SKILL.md frontmatter")})
 		return
 	}
 	if slug == "" {
 		slug = slugify(name)
 	}
 	if !slugRegexp.MatchString(slug) {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "slug must be a valid slug (lowercase letters, numbers, hyphens only)"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidSlug, "slug")})
 		return
 	}
 
@@ -107,7 +109,7 @@ func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
 	// Extract to filesystem: baseDir/slug/version/
 	destDir := filepath.Join(h.baseDir, slug, fmt.Sprintf("%d", version))
 	if err := os.MkdirAll(destDir, 0755); err != nil {
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to create skill directory"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgInternalError, "failed to create skill directory")})
 		return
 	}
 
@@ -167,7 +169,7 @@ func (h *SkillsHandler) handleUpload(w http.ResponseWriter, r *http.Request) {
 
 	id, err := h.skills.CreateSkillManaged(r.Context(), skill)
 	if err != nil {
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to save skill: " + err.Error()})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToCreate, "skill", err.Error())})
 		return
 	}
 
diff --git a/internal/http/skills_versions.go b/internal/http/skills_versions.go
index a295f8f4..a2a48cf8 100644
--- a/internal/http/skills_versions.go
+++ b/internal/http/skills_versions.go
@@ -10,19 +10,23 @@ import (
 	"strings"
 
 	"github.com/google/uuid"
+
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
+	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
 // handleListVersions returns all available version numbers for a skill.
 func (h *SkillsHandler) handleListVersions(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
 	_, slug, currentVersion, ok := h.skills.GetSkillFilePath(id)
 	if !ok {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "skill not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "skill", id.String())})
 		return
 	}
 
@@ -60,15 +64,16 @@ func (h *SkillsHandler) handleListVersions(w http.ResponseWriter, r *http.Reques
 
 // handleListFiles returns all files in a skill version directory.
 func (h *SkillsHandler) handleListFiles(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
 	_, slug, currentVersion, ok := h.skills.GetSkillFilePath(id)
 	if !ok {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "skill not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "skill", id.String())})
 		return
 	}
 
@@ -76,7 +81,7 @@ func (h *SkillsHandler) handleListFiles(w http.ResponseWriter, r *http.Request)
 	if v := r.URL.Query().Get("version"); v != "" {
 		parsed, err := strconv.Atoi(v)
 		if err != nil || parsed < 1 {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid version"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidVersion)})
 			return
 		}
 		version = parsed
@@ -84,7 +89,7 @@ func (h *SkillsHandler) handleListFiles(w http.ResponseWriter, r *http.Request)
 
 	versionDir := filepath.Join(h.baseDir, slug, strconv.Itoa(version))
 	if _, err := os.Stat(versionDir); err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "version not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgVersionNotFound)})
 		return
 	}
 
@@ -137,26 +142,27 @@ func (h *SkillsHandler) handleListFiles(w http.ResponseWriter, r *http.Request)
 
 // handleReadFile reads a single file from a skill version directory.
 func (h *SkillsHandler) handleReadFile(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	id, err := uuid.Parse(r.PathValue("id"))
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid skill ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "skill")})
 		return
 	}
 
 	relPath := r.PathValue("path")
 	if relPath == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "path is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "path")})
 		return
 	}
 	if strings.Contains(relPath, "..") {
 		slog.Warn("security.skill_files_traversal", "path", relPath)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	_, slug, currentVersion, ok := h.skills.GetSkillFilePath(id)
 	if !ok {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "skill not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "skill", id.String())})
 		return
 	}
 
@@ -164,7 +170,7 @@ func (h *SkillsHandler) handleReadFile(w http.ResponseWriter, r *http.Request) {
 	if v := r.URL.Query().Get("version"); v != "" {
 		parsed, err := strconv.Atoi(v)
 		if err != nil || parsed < 1 {
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid version"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidVersion)})
 			return
 		}
 		version = parsed
@@ -176,31 +182,31 @@ func (h *SkillsHandler) handleReadFile(w http.ResponseWriter, r *http.Request) {
 	// Verify resolved path is within the version directory
 	if !strings.HasPrefix(absPath, versionDir+string(filepath.Separator)) {
 		slog.Warn("security.skill_files_escape", "resolved", absPath, "root", versionDir)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	// Use Lstat to detect symlinks — reject them to prevent directory escape
 	info, err := os.Lstat(absPath)
 	if err != nil || info.IsDir() {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "file not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgFileNotFound)})
 		return
 	}
 	if info.Mode()&os.ModeSymlink != 0 {
 		slog.Warn("security.skill_files_symlink", "path", absPath)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	// Skip system artifacts
 	if isSystemArtifact(relPath) {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "file not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgFileNotFound)})
 		return
 	}
 
 	data, err := os.ReadFile(absPath)
 	if err != nil {
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to read file"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToReadFile)})
 		return
 	}
 
diff --git a/internal/http/storage.go b/internal/http/storage.go
index dab3109b..969d8930 100644
--- a/internal/http/storage.go
+++ b/internal/http/storage.go
@@ -6,6 +6,8 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 )
 
 // StorageHandler provides HTTP endpoints for browsing and managing
@@ -33,7 +35,8 @@ func (h *StorageHandler) auth(next http.HandlerFunc) http.HandlerFunc {
 		if h.token != "" {
 			provided := extractBearerToken(r)
 			if !tokenMatch(provided, h.token) {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
@@ -65,10 +68,11 @@ func isProtectedPath(rel string) bool {
 // handleList lists all files and directories under ~/.goclaw/.
 // Optional query param ?path= scopes the listing to a subtree.
 func (h *StorageHandler) handleList(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	subPath := r.URL.Query().Get("path")
 	if strings.Contains(subPath, "..") {
 		slog.Warn("security.storage_traversal", "path", subPath)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
@@ -77,7 +81,7 @@ func (h *StorageHandler) handleList(w http.ResponseWriter, r *http.Request) {
 		rootDir = filepath.Join(h.baseDir, filepath.Clean(subPath))
 		if !strings.HasPrefix(rootDir, h.baseDir) {
 			slog.Warn("security.storage_escape", "resolved", rootDir, "root", h.baseDir)
-			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+			writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 			return
 		}
 	}
@@ -87,8 +91,8 @@ func (h *StorageHandler) handleList(w http.ResponseWriter, r *http.Request) {
 		Name      string `json:"name"`
 		IsDir     bool   `json:"isDir"`
 		Size      int64  `json:"size"`
-		TotalSize int64  `json:"totalSize"`  // recursive size for directories
-		Protected bool   `json:"protected"`  // true if deletion is blocked
+		TotalSize int64  `json:"totalSize"` // recursive size for directories
+		Protected bool   `json:"protected"` // true if deletion is blocked
 	}
 
 	// Compute directory sizes via a two-pass approach:
@@ -180,38 +184,39 @@ func (h *StorageHandler) handleList(w http.ResponseWriter, r *http.Request) {
 
 // handleRead reads a single file's content by relative path.
 func (h *StorageHandler) handleRead(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	relPath := r.PathValue("path")
 	if relPath == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "path is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "path")})
 		return
 	}
 	if strings.Contains(relPath, "..") {
 		slog.Warn("security.storage_traversal", "path", relPath)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	absPath := filepath.Join(h.baseDir, filepath.Clean(relPath))
 	if !strings.HasPrefix(absPath, h.baseDir+string(filepath.Separator)) {
 		slog.Warn("security.storage_escape", "resolved", absPath, "root", h.baseDir)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	info, err := os.Lstat(absPath)
 	if err != nil || info.IsDir() {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "file not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgFileNotFound)})
 		return
 	}
 	if info.Mode()&os.ModeSymlink != 0 {
 		slog.Warn("security.storage_symlink", "path", absPath)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	data, err := os.ReadFile(absPath)
 	if err != nil {
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to read file"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToReadFile)})
 		return
 	}
 
@@ -225,33 +230,34 @@ func (h *StorageHandler) handleRead(w http.ResponseWriter, r *http.Request) {
 // handleDelete removes a file or directory (recursively).
 // Rejects deletion of the root dir and any path inside excluded directories.
 func (h *StorageHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
 	relPath := r.PathValue("path")
 	if relPath == "" {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "path is required"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "path")})
 		return
 	}
 	if strings.Contains(relPath, "..") {
 		slog.Warn("security.storage_traversal", "path", relPath)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	if isProtectedPath(relPath) {
-		writeJSON(w, http.StatusForbidden, map[string]string{"error": "cannot delete skills directories"})
+		writeJSON(w, http.StatusForbidden, map[string]string{"error": i18n.T(locale, i18n.MsgCannotDeleteSkillsDir)})
 		return
 	}
 
 	absPath := filepath.Join(h.baseDir, filepath.Clean(relPath))
 	if !strings.HasPrefix(absPath, h.baseDir+string(filepath.Separator)) {
 		slog.Warn("security.storage_escape", "resolved", absPath, "root", h.baseDir)
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid path"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidPath)})
 		return
 	}
 
 	// Verify path exists
 	info, err := os.Lstat(absPath)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "path", relPath)})
 		return
 	}
 
@@ -266,7 +272,7 @@ func (h *StorageHandler) handleDelete(w http.ResponseWriter, r *http.Request) {
 
 	if err != nil {
 		slog.Error("storage.delete_failed", "path", absPath, "error", err)
-		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": "failed to delete"})
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": i18n.T(locale, i18n.MsgFailedToDeleteFile)})
 		return
 	}
 
diff --git a/internal/http/tools_invoke.go b/internal/http/tools_invoke.go
index a9530612..daaa7de9 100644
--- a/internal/http/tools_invoke.go
+++ b/internal/http/tools_invoke.go
@@ -2,10 +2,10 @@ package http
 
 import (
 	"encoding/json"
-	"fmt"
 	"log/slog"
 	"net/http"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 	"github.com/nextlevelbuilder/goclaw/internal/tools"
 )
@@ -39,26 +39,28 @@ type toolsInvokeRequest struct {
 }
 
 func (h *ToolsInvokeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	locale := extractLocale(r)
+
 	if r.Method != http.MethodPost {
-		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		writeJSON(w, http.StatusMethodNotAllowed, map[string]string{"error": i18n.T(locale, i18n.MsgMethodNotAllowed)})
 		return
 	}
 
 	if h.token != "" {
 		if extractBearerToken(r) != h.token {
-			http.Error(w, `{"error":{"code":"UNAUTHORIZED","message":"Invalid token"}}`, http.StatusUnauthorized)
+			writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 			return
 		}
 	}
 
 	var req toolsInvokeRequest
 	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		http.Error(w, fmt.Sprintf(`{"error":{"code":"BAD_REQUEST","message":"%s"}}`, err), http.StatusBadRequest)
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidJSON)})
 		return
 	}
 
 	if req.Tool == "" {
-		http.Error(w, `{"error":{"code":"BAD_REQUEST","message":"tool is required"}}`, http.StatusBadRequest)
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgRequired, "tool")})
 		return
 	}
 
@@ -68,7 +70,7 @@ func (h *ToolsInvokeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		// Just check if tool exists and return its schema
 		tool, ok := h.registry.Get(req.Tool)
 		if !ok {
-			writeToolError(w, http.StatusNotFound, "NOT_FOUND", fmt.Sprintf("Tool '%s' not found", req.Tool))
+			writeToolError(w, http.StatusNotFound, "NOT_FOUND", i18n.T(locale, i18n.MsgNotFound, "tool", req.Tool))
 			return
 		}
 
diff --git a/internal/http/traces.go b/internal/http/traces.go
index 11684b1e..d9fdb74e 100644
--- a/internal/http/traces.go
+++ b/internal/http/traces.go
@@ -6,6 +6,7 @@ import (
 
 	"github.com/google/uuid"
 
+	"github.com/nextlevelbuilder/goclaw/internal/i18n"
 	"github.com/nextlevelbuilder/goclaw/internal/store"
 )
 
@@ -30,10 +31,14 @@ func (h *TracesHandler) authMiddleware(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		if h.token != "" {
 			if extractBearerToken(r) != h.token {
-				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": "unauthorized"})
+				locale := extractLocale(r)
+				writeJSON(w, http.StatusUnauthorized, map[string]string{"error": i18n.T(locale, i18n.MsgUnauthorized)})
 				return
 			}
 		}
+		locale := extractLocale(r)
+		ctx := store.WithLocale(r.Context(), locale)
+		r = r.WithContext(ctx)
 		next(w, r)
 	}
 }
@@ -87,16 +92,17 @@ func (h *TracesHandler) handleList(w http.ResponseWriter, r *http.Request) {
 }
 
 func (h *TracesHandler) handleGet(w http.ResponseWriter, r *http.Request) {
+	locale := store.LocaleFromContext(r.Context())
 	traceIDStr := r.PathValue("traceID")
 	traceID, err := uuid.Parse(traceIDStr)
 	if err != nil {
-		writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid trace ID"})
+		writeJSON(w, http.StatusBadRequest, map[string]string{"error": i18n.T(locale, i18n.MsgInvalidID, "trace")})
 		return
 	}
 
 	trace, err := h.tracing.GetTrace(r.Context(), traceID)
 	if err != nil {
-		writeJSON(w, http.StatusNotFound, map[string]string{"error": "trace not found"})
+		writeJSON(w, http.StatusNotFound, map[string]string{"error": i18n.T(locale, i18n.MsgNotFound, "trace", traceIDStr)})
 		return
 	}
 
diff --git a/internal/i18n/catalog_en.go b/internal/i18n/catalog_en.go
new file mode 100644
index 00000000..8d6e614c
--- /dev/null
+++ b/internal/i18n/catalog_en.go
@@ -0,0 +1,132 @@
+package i18n
+
+func init() {
+	register(LocaleEN, map[string]string{
+		// Common validation
+		MsgRequired:         "%s is required",
+		MsgInvalidID:        "invalid %s ID",
+		MsgNotFound:         "%s not found: %s",
+		MsgAlreadyExists:    "%s already exists: %s",
+		MsgInvalidRequest:   "invalid request: %s",
+		MsgInvalidJSON:      "invalid JSON",
+		MsgUnauthorized:     "unauthorized",
+		MsgPermissionDenied: "permission denied: insufficient role for %s",
+		MsgInternalError:    "internal error: %s",
+		MsgInvalidSlug:      "%s must be a valid slug (lowercase letters, numbers, hyphens only)",
+		MsgFailedToList:     "failed to list %s",
+		MsgFailedToCreate:   "failed to create %s: %s",
+		MsgFailedToUpdate:   "failed to update %s: %s",
+		MsgFailedToDelete:   "failed to delete %s: %s",
+		MsgFailedToSave:     "failed to save %s: %s",
+		MsgInvalidUpdates:   "invalid updates",
+
+		// Agent
+		MsgAgentNotFound:       "agent not found: %s",
+		MsgCannotDeleteDefault: "cannot delete the default agent",
+		MsgUserCtxRequired:     "user context required",
+
+		// Chat
+		MsgRateLimitExceeded: "rate limit exceeded — please wait",
+		MsgNoUserMessage:     "no user message found",
+		MsgUserIDRequired:    "user_id is required",
+		MsgMsgRequired:       "message is required",
+
+		// Channel instances
+		MsgInvalidChannelType: "invalid channel_type",
+		MsgInstanceNotFound:   "instance not found",
+
+		// Cron
+		MsgJobNotFound:     "job not found",
+		MsgInvalidCronExpr: "invalid cron expression: %s",
+
+		// Config
+		MsgConfigHashMismatch: "config has changed (hash mismatch)",
+
+		// Exec approval
+		MsgExecApprovalDisabled: "exec approval is not enabled",
+
+		// Pairing
+		MsgSenderChannelRequired: "senderId and channel are required",
+		MsgCodeRequired:          "code is required",
+		MsgSenderIDRequired:      "sender_id is required",
+
+		// HTTP API
+		MsgInvalidAuth:           "invalid authentication",
+		MsgMsgsRequired:          "messages is required",
+		MsgUserIDHeader:          "X-GoClaw-User-Id header is required in managed mode",
+		MsgFileTooLarge:          "file too large or invalid multipart form",
+		MsgMissingFileField:      "missing 'file' field",
+		MsgInvalidFilename:       "invalid filename",
+		MsgChannelKeyReq:         "channel and key are required",
+		MsgMethodNotAllowed:      "method not allowed",
+		MsgStreamingNotSupported: "streaming not supported",
+		MsgOwnerOnly:             "only owner can %s",
+		MsgNoAccess:              "no access to this %s",
+		MsgAlreadySummoning:      "agent is already being summoned",
+		MsgSummoningUnavailable:  "summoning not available",
+		MsgNoDescription:         "agent has no description to resummon from",
+		MsgInvalidPath:           "invalid path",
+
+		// Scheduler
+		MsgQueueFull:    "session queue is full",
+		MsgShuttingDown: "gateway is shutting down, please retry shortly",
+
+		// Provider
+		MsgProviderReqFailed: "%s: request failed: %s",
+
+		// Unknown method
+		MsgUnknownMethod: "unknown method: %s",
+
+		// Not implemented
+		MsgNotImplemented: "%s not yet implemented",
+
+		// Agent links
+		MsgLinksNotConfigured:   "agent links not configured",
+		MsgInvalidDirection:     "direction must be outbound, inbound, or bidirectional",
+		MsgSourceTargetSame:     "source and target must be different agents",
+		MsgCannotDelegateOpen:   "cannot delegate to open agents — only predefined agents can be delegation targets",
+		MsgNoUpdatesProvided:    "no updates provided",
+		MsgInvalidLinkStatus:    "status must be active or disabled",
+
+		// Teams
+		MsgTeamsNotConfigured:   "teams not configured",
+		MsgAgentIsTeamLead:      "agent is already the team lead",
+		MsgCannotRemoveTeamLead: "cannot remove the team lead",
+
+		// Delegations
+		MsgDelegationsUnavailable: "delegations not available",
+
+		// Channels
+		MsgCannotDeleteDefaultInst: "cannot delete default channel instance",
+
+		// Skills
+		MsgSkillsUpdateNotSupported: "skills.update not supported for file-based skills",
+		MsgCannotResolveSkillID:     "cannot resolve skill ID for file-based skill",
+
+		// Logs
+		MsgInvalidLogAction: "action must be 'start' or 'stop'",
+
+		// Config
+		MsgRawConfigRequired: "raw config is required",
+		MsgRawPatchRequired:  "raw patch is required",
+
+		// Storage / File
+		MsgCannotDeleteSkillsDir: "cannot delete skills directories",
+		MsgFailedToReadFile:      "failed to read file",
+		MsgFileNotFound:          "file not found",
+		MsgInvalidVersion:        "invalid version",
+		MsgVersionNotFound:       "version not found",
+		MsgFailedToDeleteFile:    "failed to delete",
+
+		// OAuth
+		MsgNoPendingOAuth:    "no pending OAuth flow",
+		MsgFailedToSaveToken: "failed to save token",
+
+		// Knowledge Graph
+		MsgEntityIDRequired:       "entity_id is required",
+		MsgEntityFieldsRequired:   "external_id, name, and entity_type are required",
+		MsgTextRequired:           "text is required",
+		MsgProviderModelRequired:  "provider and model are required",
+		MsgInvalidProviderOrModel: "invalid provider or model",
+	})
+}
diff --git a/internal/i18n/catalog_vi.go b/internal/i18n/catalog_vi.go
new file mode 100644
index 00000000..533087ff
--- /dev/null
+++ b/internal/i18n/catalog_vi.go
@@ -0,0 +1,132 @@
+package i18n
+
+func init() {
+	register(LocaleVI, map[string]string{
+		// Common validation
+		MsgRequired:         "%s là bắt buộc",
+		MsgInvalidID:        "ID %s không hợp lệ",
+		MsgNotFound:         "không tìm thấy %s: %s",
+		MsgAlreadyExists:    "%s đã tồn tại: %s",
+		MsgInvalidRequest:   "yêu cầu không hợp lệ: %s",
+		MsgInvalidJSON:      "JSON không hợp lệ",
+		MsgUnauthorized:     "chưa xác thực",
+		MsgPermissionDenied: "từ chối quyền truy cập: không đủ quyền cho %s",
+		MsgInternalError:    "lỗi nội bộ: %s",
+		MsgInvalidSlug:      "%s phải là slug hợp lệ (chữ thường, số, dấu gạch ngang)",
+		MsgFailedToList:     "không thể liệt kê %s",
+		MsgFailedToCreate:   "không thể tạo %s: %s",
+		MsgFailedToUpdate:   "không thể cập nhật %s: %s",
+		MsgFailedToDelete:   "không thể xóa %s: %s",
+		MsgFailedToSave:     "không thể lưu %s: %s",
+		MsgInvalidUpdates:   "cập nhật không hợp lệ",
+
+		// Agent
+		MsgAgentNotFound:       "không tìm thấy agent: %s",
+		MsgCannotDeleteDefault: "không thể xóa agent mặc định",
+		MsgUserCtxRequired:     "yêu cầu ngữ cảnh người dùng",
+
+		// Chat
+		MsgRateLimitExceeded: "vượt quá giới hạn tốc độ — vui lòng đợi",
+		MsgNoUserMessage:     "không tìm thấy tin nhắn người dùng",
+		MsgUserIDRequired:    "user_id là bắt buộc",
+		MsgMsgRequired:       "tin nhắn là bắt buộc",
+
+		// Channel instances
+		MsgInvalidChannelType: "loại channel không hợp lệ",
+		MsgInstanceNotFound:   "không tìm thấy phiên bản",
+
+		// Cron
+		MsgJobNotFound:     "không tìm thấy tác vụ",
+		MsgInvalidCronExpr: "biểu thức cron không hợp lệ: %s",
+
+		// Config
+		MsgConfigHashMismatch: "cấu hình đã thay đổi (hash không khớp)",
+
+		// Exec approval
+		MsgExecApprovalDisabled: "phê duyệt thực thi chưa được bật",
+
+		// Pairing
+		MsgSenderChannelRequired: "senderId và channel là bắt buộc",
+		MsgCodeRequired:          "mã là bắt buộc",
+		MsgSenderIDRequired:      "sender_id là bắt buộc",
+
+		// HTTP API
+		MsgInvalidAuth:           "xác thực không hợp lệ",
+		MsgMsgsRequired:          "messages là bắt buộc",
+		MsgUserIDHeader:          "header X-GoClaw-User-Id là bắt buộc ở chế độ managed",
+		MsgFileTooLarge:          "tệp quá lớn hoặc form multipart không hợp lệ",
+		MsgMissingFileField:      "thiếu trường 'file'",
+		MsgInvalidFilename:       "tên tệp không hợp lệ",
+		MsgChannelKeyReq:         "channel và key là bắt buộc",
+		MsgMethodNotAllowed:      "phương thức không được phép",
+		MsgStreamingNotSupported: "streaming không được hỗ trợ",
+		MsgOwnerOnly:             "chỉ chủ sở hữu mới có thể %s",
+		MsgNoAccess:              "không có quyền truy cập %s này",
+		MsgAlreadySummoning:      "agent đang được triệu hồi",
+		MsgSummoningUnavailable:  "triệu hồi không khả dụng",
+		MsgNoDescription:         "agent không có mô tả để triệu hồi lại",
+		MsgInvalidPath:           "đường dẫn không hợp lệ",
+
+		// Scheduler
+		MsgQueueFull:    "hàng đợi session đã đầy",
+		MsgShuttingDown: "cổng đang tắt, vui lòng thử lại sau",
+
+		// Provider
+		MsgProviderReqFailed: "%s: yêu cầu thất bại: %s",
+
+		// Unknown method
+		MsgUnknownMethod: "phương thức không xác định: %s",
+
+		// Not implemented
+		MsgNotImplemented: "%s chưa được triển khai",
+
+		// Agent links
+		MsgLinksNotConfigured:   "liên kết agent chưa được cấu hình",
+		MsgInvalidDirection:     "hướng phải là outbound, inbound hoặc bidirectional",
+		MsgSourceTargetSame:     "nguồn và đích phải là các agent khác nhau",
+		MsgCannotDelegateOpen:   "không thể ủy quyền cho agent mở — chỉ agent định sẵn mới có thể là đích ủy quyền",
+		MsgNoUpdatesProvided:    "không có cập nhật nào được cung cấp",
+		MsgInvalidLinkStatus:    "trạng thái phải là active hoặc disabled",
+
+		// Teams
+		MsgTeamsNotConfigured:   "nhóm chưa được cấu hình",
+		MsgAgentIsTeamLead:      "agent đã là trưởng nhóm",
+		MsgCannotRemoveTeamLead: "không thể xóa trưởng nhóm",
+
+		// Delegations
+		MsgDelegationsUnavailable: "ủy quyền không khả dụng",
+
+		// Channels
+		MsgCannotDeleteDefaultInst: "không thể xóa phiên bản channel mặc định",
+
+		// Skills
+		MsgSkillsUpdateNotSupported: "skills.update không được hỗ trợ với skill dựa trên tệp",
+		MsgCannotResolveSkillID:     "không thể xác định ID skill dựa trên tệp",
+
+		// Logs
+		MsgInvalidLogAction: "action phải là 'start' hoặc 'stop'",
+
+		// Config
+		MsgRawConfigRequired: "cấu hình raw là bắt buộc",
+		MsgRawPatchRequired:  "patch raw là bắt buộc",
+
+		// Storage / File
+		MsgCannotDeleteSkillsDir: "không thể xóa thư mục skill",
+		MsgFailedToReadFile:      "không thể đọc tệp",
+		MsgFileNotFound:          "không tìm thấy tệp",
+		MsgInvalidVersion:        "phiên bản không hợp lệ",
+		MsgVersionNotFound:       "không tìm thấy phiên bản",
+		MsgFailedToDeleteFile:    "không thể xóa",
+
+		// OAuth
+		MsgNoPendingOAuth:    "không có luồng OAuth đang chờ",
+		MsgFailedToSaveToken: "không thể lưu token",
+
+		// Knowledge Graph
+		MsgEntityIDRequired:       "entity_id là bắt buộc",
+		MsgEntityFieldsRequired:   "external_id, name và entity_type là bắt buộc",
+		MsgTextRequired:           "text là bắt buộc",
+		MsgProviderModelRequired:  "provider và model là bắt buộc",
+		MsgInvalidProviderOrModel: "provider hoặc model không hợp lệ",
+	})
+}
diff --git a/internal/i18n/catalog_zh.go b/internal/i18n/catalog_zh.go
new file mode 100644
index 00000000..ad018797
--- /dev/null
+++ b/internal/i18n/catalog_zh.go
@@ -0,0 +1,132 @@
+package i18n
+
+func init() {
+	register(LocaleZH, map[string]string{
+		// Common validation
+		MsgRequired:         "%s 是必填项",
+		MsgInvalidID:        "无效的 %s ID",
+		MsgNotFound:         "未找到 %s：%s",
+		MsgAlreadyExists:    "%s 已存在：%s",
+		MsgInvalidRequest:   "无效请求：%s",
+		MsgInvalidJSON:      "无效的 JSON",
+		MsgUnauthorized:     "未授权",
+		MsgPermissionDenied: "权限不足：无法访问 %s",
+		MsgInternalError:    "内部错误：%s",
+		MsgInvalidSlug:      "%s 必须是有效的 slug（小写字母、数字、连字符）",
+		MsgFailedToList:     "获取 %s 列表失败",
+		MsgFailedToCreate:   "创建 %s 失败：%s",
+		MsgFailedToUpdate:   "更新 %s 失败：%s",
+		MsgFailedToDelete:   "删除 %s 失败：%s",
+		MsgFailedToSave:     "保存 %s 失败：%s",
+		MsgInvalidUpdates:   "更新内容无效",
+
+		// Agent
+		MsgAgentNotFound:       "未找到Agent：%s",
+		MsgCannotDeleteDefault: "无法删除默认Agent",
+		MsgUserCtxRequired:     "需要用户上下文",
+
+		// Chat
+		MsgRateLimitExceeded: "请求频率超限 — 请稍候",
+		MsgNoUserMessage:     "未找到用户消息",
+		MsgUserIDRequired:    "user_id 是必填项",
+		MsgMsgRequired:       "消息是必填项",
+
+		// Channel instances
+		MsgInvalidChannelType: "Channel类型无效",
+		MsgInstanceNotFound:   "未找到实例",
+
+		// Cron
+		MsgJobNotFound:     "未找到任务",
+		MsgInvalidCronExpr: "无效的 cron 表达式：%s",
+
+		// Config
+		MsgConfigHashMismatch: "配置已更改（hash 不匹配）",
+
+		// Exec approval
+		MsgExecApprovalDisabled: "执行审批未启用",
+
+		// Pairing
+		MsgSenderChannelRequired: "senderId 和 channel 是必填项",
+		MsgCodeRequired:          "代码是必填项",
+		MsgSenderIDRequired:      "sender_id 是必填项",
+
+		// HTTP API
+		MsgInvalidAuth:           "身份验证无效",
+		MsgMsgsRequired:          "messages 是必填项",
+		MsgUserIDHeader:          "托管模式下需要 X-GoClaw-User-Id 请求头",
+		MsgFileTooLarge:          "文件过大或 multipart 表单无效",
+		MsgMissingFileField:      "缺少 'file' 字段",
+		MsgInvalidFilename:       "文件名无效",
+		MsgChannelKeyReq:         "channel 和 key 是必填项",
+		MsgMethodNotAllowed:      "不允许的请求方法",
+		MsgStreamingNotSupported: "不支持流式传输",
+		MsgOwnerOnly:             "只有所有者才能%s",
+		MsgNoAccess:              "无权访问此%s",
+		MsgAlreadySummoning:      "Agent正在被召唤中",
+		MsgSummoningUnavailable:  "召唤功能不可用",
+		MsgNoDescription:         "Agent没有可供重新召唤的描述",
+		MsgInvalidPath:           "路径无效",
+
+		// Scheduler
+		MsgQueueFull:    "Session队列已满",
+		MsgShuttingDown: "网关正在关闭，请稍后重试",
+
+		// Provider
+		MsgProviderReqFailed: "%s：请求失败：%s",
+
+		// Unknown method
+		MsgUnknownMethod: "未知方法：%s",
+
+		// Not implemented
+		MsgNotImplemented: "%s 尚未实现",
+
+		// Agent links
+		MsgLinksNotConfigured:   "Agent链接未配置",
+		MsgInvalidDirection:     "方向必须是 outbound、inbound 或 bidirectional",
+		MsgSourceTargetSame:     "源和目标必须是不同的Agent",
+		MsgCannotDelegateOpen:   "无法委派给开放型Agent — 只有预定义Agent才能作为委派目标",
+		MsgNoUpdatesProvided:    "未提供更新内容",
+		MsgInvalidLinkStatus:    "状态必须是 active 或 disabled",
+
+		// Teams
+		MsgTeamsNotConfigured:   "团队未配置",
+		MsgAgentIsTeamLead:      "该Agent已是团队负责人",
+		MsgCannotRemoveTeamLead: "无法移除团队负责人",
+
+		// Delegations
+		MsgDelegationsUnavailable: "委派功能不可用",
+
+		// Channels
+		MsgCannotDeleteDefaultInst: "无法删除默认Channel实例",
+
+		// Skills
+		MsgSkillsUpdateNotSupported: "基于文件的Skill不支持 skills.update",
+		MsgCannotResolveSkillID:     "无法解析基于文件的Skill ID",
+
+		// Logs
+		MsgInvalidLogAction: "action 必须是 'start' 或 'stop'",
+
+		// Config
+		MsgRawConfigRequired: "raw 配置是必填项",
+		MsgRawPatchRequired:  "raw 补丁是必填项",
+
+		// Storage / File
+		MsgCannotDeleteSkillsDir: "无法删除Skill目录",
+		MsgFailedToReadFile:      "读取文件失败",
+		MsgFileNotFound:          "文件未找到",
+		MsgInvalidVersion:        "版本无效",
+		MsgVersionNotFound:       "未找到该版本",
+		MsgFailedToDeleteFile:    "删除失败",
+
+		// OAuth
+		MsgNoPendingOAuth:    "没有待处理的 OAuth 流程",
+		MsgFailedToSaveToken: "保存令牌失败",
+
+		// Knowledge Graph
+		MsgEntityIDRequired:       "entity_id 是必填项",
+		MsgEntityFieldsRequired:   "external_id、name 和 entity_type 是必填项",
+		MsgTextRequired:           "text 是必填项",
+		MsgProviderModelRequired:  "provider 和 model 是必填项",
+		MsgInvalidProviderOrModel: "provider 或 model 无效",
+	})
+}
diff --git a/internal/i18n/i18n.go b/internal/i18n/i18n.go
new file mode 100644
index 00000000..f5c84d69
--- /dev/null
+++ b/internal/i18n/i18n.go
@@ -0,0 +1,80 @@
+// Package i18n provides a lightweight message catalog for localizing
+// user-facing error messages. Messages use fmt.Sprintf-style templates.
+package i18n
+
+import "fmt"
+
+// Supported locales.
+const (
+	LocaleEN = "en"
+	LocaleVI = "vi"
+	LocaleZH = "zh"
+
+	DefaultLocale = LocaleEN
+)
+
+// catalogs maps locale → key → message template.
+var catalogs = map[string]map[string]string{}
+
+// register adds a set of messages for a locale. Called from catalog_*.go init().
+func register(locale string, msgs map[string]string) {
+	if catalogs[locale] == nil {
+		catalogs[locale] = make(map[string]string, len(msgs))
+	}
+	for k, v := range msgs {
+		catalogs[locale][k] = v
+	}
+}
+
+// T returns a localized message for the given key.
+// If the key is not found in the requested locale, it falls back to English.
+// If the key is not found in English either, the key itself is returned.
+// Optional args are applied via fmt.Sprintf if the template contains verbs.
+func T(locale, key string, args ...any) string {
+	msg := lookup(locale, key)
+	if len(args) > 0 {
+		return fmt.Sprintf(msg, args...)
+	}
+	return msg
+}
+
+func lookup(locale, key string) string {
+	if cat, ok := catalogs[locale]; ok {
+		if msg, ok := cat[key]; ok {
+			return msg
+		}
+	}
+	// Fallback to English
+	if locale != LocaleEN {
+		if cat, ok := catalogs[LocaleEN]; ok {
+			if msg, ok := cat[key]; ok {
+				return msg
+			}
+		}
+	}
+	return key
+}
+
+// IsSupported returns true if the locale is a known language.
+func IsSupported(locale string) bool {
+	switch locale {
+	case LocaleEN, LocaleVI, LocaleZH:
+		return true
+	}
+	return false
+}
+
+// Normalize returns a supported locale or the default.
+func Normalize(locale string) string {
+	if IsSupported(locale) {
+		return locale
+	}
+	// Handle common prefixes: "en-US" → "en", "vi-VN" → "vi", "zh-CN" → "zh"
+	if len(locale) >= 2 {
+		prefix := locale[:2]
+		if IsSupported(prefix) {
+			return prefix
+		}
+	}
+	return DefaultLocale
+}
diff --git a/internal/i18n/keys.go b/internal/i18n/keys.go
new file mode 100644
index 00000000..d59c18bf
--- /dev/null
+++ b/internal/i18n/keys.go
@@ -0,0 +1,132 @@
+package i18n
+
+// Message keys for gateway/HTTP error messages.
+// Grouped by domain for easier maintenance.
+const (
+	// --- Common validation ---
+	MsgRequired          = "error.required"           // "%s is required"
+	MsgInvalidID         = "error.invalid_id"         // "invalid %s ID"
+	MsgNotFound          = "error.not_found"          // "%s not found: %s"
+	MsgAlreadyExists     = "error.already_exists"     // "%s already exists: %s"
+	MsgInvalidRequest    = "error.invalid_request"    // "invalid request: %s"
+	MsgInvalidJSON       = "error.invalid_json"       // "invalid JSON"
+	MsgUnauthorized      = "error.unauthorized"       // "unauthorized"
+	MsgPermissionDenied  = "error.permission_denied"  // "permission denied: insufficient role for %s"
+	MsgInternalError     = "error.internal"           // "internal error: %s"
+	MsgInvalidSlug       = "error.invalid_slug"       // "%s must be a valid slug (lowercase letters, numbers, hyphens only)"
+	MsgFailedToList      = "error.failed_to_list"     // "failed to list %s"
+	MsgFailedToCreate    = "error.failed_to_create"   // "failed to create %s: %s"
+	MsgFailedToUpdate    = "error.failed_to_update"   // "failed to update %s: %s"
+	MsgFailedToDelete    = "error.failed_to_delete"   // "failed to delete %s: %s"
+	MsgFailedToSave      = "error.failed_to_save"     // "failed to save %s: %s"
+	MsgInvalidUpdates    = "error.invalid_updates"    // "invalid updates"
+
+	// --- Agent ---
+	MsgAgentNotFound       = "error.agent_not_found"        // "agent not found: %s"
+	MsgCannotDeleteDefault = "error.cannot_delete_default"   // "cannot delete the default agent"
+	MsgUserCtxRequired     = "error.user_ctx_required"       // "user context required"
+
+	// --- Chat ---
+	MsgRateLimitExceeded = "error.rate_limit"          // "rate limit exceeded — please wait"
+	MsgNoUserMessage     = "error.no_user_message"     // "no user message found"
+	MsgUserIDRequired    = "error.user_id_required"    // "user_id is required"
+	MsgMsgRequired       = "error.message_required"    // "message is required"
+
+	// --- Channel instances ---
+	MsgInvalidChannelType = "error.invalid_channel_type" // "invalid channel_type"
+	MsgInstanceNotFound   = "error.instance_not_found"   // "instance not found"
+
+	// --- Cron ---
+	MsgJobNotFound     = "error.job_not_found"     // "job not found"
+	MsgInvalidCronExpr = "error.invalid_cron_expr" // "invalid cron expression: %s"
+
+	// --- Config ---
+	MsgConfigHashMismatch = "error.config_hash_mismatch" // "config has changed (hash mismatch)"
+
+	// --- Exec approval ---
+	MsgExecApprovalDisabled = "error.exec_approval_disabled" // "exec approval is not enabled"
+
+	// --- Pairing ---
+	MsgSenderChannelRequired = "error.sender_channel_required" // "senderId and channel are required"
+	MsgCodeRequired          = "error.code_required"           // "code is required"
+	MsgSenderIDRequired      = "error.sender_id_required"      // "sender_id is required"
+
+	// --- HTTP API ---
+	MsgInvalidAuth          = "error.invalid_auth"              // "invalid authentication"
+	MsgMsgsRequired         = "error.messages_required"         // "messages is required"
+	MsgUserIDHeader         = "error.user_id_header"            // "X-GoClaw-User-Id header is required"
+	MsgFileTooLarge         = "error.file_too_large"            // "file too large or invalid multipart form"
+	MsgMissingFileField     = "error.missing_file_field"        // "missing 'file' field"
+	MsgInvalidFilename      = "error.invalid_filename"          // "invalid filename"
+	MsgChannelKeyReq        = "error.channel_key_required"      // "channel and key are required"
+	MsgMethodNotAllowed     = "error.method_not_allowed"        // "method not allowed"
+	MsgStreamingNotSupported = "error.streaming_not_supported"  // "streaming not supported"
+	MsgOwnerOnly            = "error.owner_only"                // "only owner can %s"
+	MsgNoAccess             = "error.no_access"                 // "no access to this %s"
+	MsgAlreadySummoning     = "error.already_summoning"         // "agent is already being summoned"
+	MsgSummoningUnavailable = "error.summoning_unavailable"     // "summoning not available"
+	MsgNoDescription        = "error.no_description"            // "agent has no description to resummon from"
+	MsgInvalidPath          = "error.invalid_path"              // "invalid path"
+
+	// --- Scheduler ---
+	MsgQueueFull       = "error.queue_full"       // "session queue is full"
+	MsgShuttingDown    = "error.shutting_down"     // "gateway is shutting down, please retry shortly"
+
+	// --- Provider ---
+	MsgProviderReqFailed = "error.provider_request_failed" // "%s: request failed: %s"
+
+	// --- Unknown method ---
+	MsgUnknownMethod = "error.unknown_method" // "unknown method: %s"
+
+	// --- Not implemented ---
+	MsgNotImplemented = "error.not_implemented" // "%s not yet implemented"
+
+	// --- Agent links ---
+	MsgLinksNotConfigured   = "error.links_not_configured"    // "agent links not configured"
+	MsgInvalidDirection     = "error.invalid_direction"       // "direction must be outbound, inbound, or bidirectional"
+	MsgSourceTargetSame     = "error.source_target_same"      // "source and target must be different agents"
+	MsgCannotDelegateOpen   = "error.cannot_delegate_open"    // "cannot delegate to open agents — only predefined agents can be delegation targets"
+	MsgNoUpdatesProvided    = "error.no_updates_provided"     // "no updates provided"
+	MsgInvalidLinkStatus    = "error.invalid_link_status"     // "status must be active or disabled"
+
+	// --- Teams ---
+	MsgTeamsNotConfigured   = "error.teams_not_configured"    // "teams not configured"
+	MsgAgentIsTeamLead      = "error.agent_is_team_lead"      // "agent is already the team lead"
+	MsgCannotRemoveTeamLead = "error.cannot_remove_team_lead" // "cannot remove the team lead"
+
+	// --- Delegations ---
+	MsgDelegationsUnavailable = "error.delegations_not_available" // "delegations not available"
+
+	// --- Channels ---
+	MsgCannotDeleteDefaultInst  = "error.cannot_delete_default_inst"  // "cannot delete default channel instance"
+
+	// --- Skills ---
+	MsgSkillsUpdateNotSupported = "error.skills_update_not_supported" // "skills.update not supported for file-based skills"
+	MsgCannotResolveSkillID     = "error.cannot_resolve_skill_id"     // "cannot resolve skill ID for file-based skill"
+
+	// --- Logs ---
+	MsgInvalidLogAction = "error.invalid_log_action" // "action must be 'start' or 'stop'"
+
+	// --- Config ---
+	MsgRawConfigRequired = "error.raw_config_required" // "raw config is required"
+	MsgRawPatchRequired  = "error.raw_patch_required"  // "raw patch is required"
+
+	// --- Storage / File ---
+	MsgCannotDeleteSkillsDir = "error.cannot_delete_skills_dir" // "cannot delete skills directories"
+	MsgFailedToReadFile      = "error.failed_to_read_file"      // "failed to read file"
+	MsgFileNotFound          = "error.file_not_found"           // "file not found"
+	MsgInvalidVersion        = "error.invalid_version"          // "invalid version"
+	MsgVersionNotFound       = "error.version_not_found"        // "version not found"
+	MsgFailedToDeleteFile    = "error.failed_to_delete_file"    // "failed to delete"
+
+	// --- OAuth ---
+	MsgNoPendingOAuth    = "error.no_pending_oauth"    // "no pending OAuth flow"
+	MsgFailedToSaveToken = "error.failed_to_save_token" // "failed to save token"
+
+	// --- Knowledge Graph ---
+	MsgEntityIDRequired           = "error.entity_id_required"            // "entity_id is required"
+	MsgEntityFieldsRequired       = "error.entity_fields_required"        // "external_id, name, and entity_type are required"
+	MsgTextRequired               = "error.text_required"                 // "text is required"
+	MsgProviderModelRequired      = "error.provider_model_required"       // "provider and model are required"
+	MsgInvalidProviderOrModel     = "error.invalid_provider_or_model"     // "invalid provider or model"
+)
diff --git a/internal/store/context.go b/internal/store/context.go
index c27c2a86..4edfad5c 100644
--- a/internal/store/context.go
+++ b/internal/store/context.go
@@ -21,6 +21,8 @@ const (
 	SenderIDKey contextKey = "goclaw_sender_id"
 	// SelfEvolveKey indicates whether a predefined agent can update its SOUL.md.
 	SelfEvolveKey contextKey = "goclaw_self_evolve"
+	// LocaleKey is the context key for the user's preferred locale (e.g. "en", "vi", "zh").
+	LocaleKey contextKey = "goclaw_locale"
 )
 
 // WithUserID returns a new context with the given user ID.
@@ -87,3 +89,16 @@ func SelfEvolveFromContext(ctx context.Context) bool {
 	}
 	return false
 }
+
+// WithLocale returns a new context with the given locale.
+func WithLocale(ctx context.Context, locale string) context.Context {
+	return context.WithValue(ctx, LocaleKey, locale)
+}
+
+// LocaleFromContext extracts the locale from context. Returns "en" if not set.
+func LocaleFromContext(ctx context.Context) string {
+	if v, ok := ctx.Value(LocaleKey).(string); ok && v != "" {
+		return v
+	}
+	return "en"
+}
diff --git a/ui/web/package.json b/ui/web/package.json
index 4d7dd850..bdf99949 100644
--- a/ui/web/package.json
+++ b/ui/web/package.json
@@ -22,10 +22,12 @@
     "d3-force": "^3.0.0",
     "framer-motion": "^12.34.3",
     "highlight.js": "^11.11.1",
+    "i18next": "^25.8.15",
     "lucide-react": "^0.468.0",
     "radix-ui": "^1.4.3",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
+    "react-i18next": "^16.5.6",
     "react-markdown": "^10.1.0",
     "react-router": "^7.1.0",
     "rehype-highlight": "^7.0.2",
diff --git a/ui/web/pnpm-lock.yaml b/ui/web/pnpm-lock.yaml
index 25412849..17212fe9 100644
--- a/ui/web/pnpm-lock.yaml
+++ b/ui/web/pnpm-lock.yaml
@@ -44,6 +44,9 @@ importers:
       highlight.js:
         specifier: ^11.11.1
         version: 11.11.1
+      i18next:
+        specifier: ^25.8.15
+        version: 25.8.15(typescript@5.7.3)
       lucide-react:
         specifier: ^0.468.0
         version: 0.468.0(react@19.2.4)
@@ -56,6 +59,9 @@ importers:
       react-dom:
         specifier: ^19.0.0
         version: 19.2.4(react@19.2.4)
+      react-i18next:
+        specifier: ^16.5.6
+        version: 16.5.6(i18next@25.8.15(typescript@5.7.3))(react-dom@19.2.4(react@19.2.4))(react@19.2.4)(typescript@5.7.3)
       react-markdown:
         specifier: ^10.1.0
         version: 10.1.0(@types/react@19.2.14)(react@19.2.4)
@@ -179,6 +185,10 @@ packages:
     peerDependencies:
       '@babel/core': ^7.0.0-0
 
+  '@babel/runtime@7.28.6':
+    resolution: {integrity: sha512-05WQkdpL9COIMz4LjTxGpPNCdlpyimKppYNoJ5Di5EUObifl8t4tuLuUBBZEpoLYOmfvIWrsp9fCl0HoPRVTdA==}
+    engines: {node: '>=6.9.0'}
+
   '@babel/template@7.28.6':
     resolution: {integrity: sha512-YA6Ma2KsCdGb+WC6UpBVFJGXL58MDA6oyONbjyF/+5sBgxY/dwkhLogbMT2GXXyU84/IhRw/2D1Os1B/giz+BQ==}
     engines: {node: '>=6.9.0'}
@@ -1654,9 +1664,20 @@ packages:
     resolution: {integrity: sha512-Xwwo44whKBVCYoliBQwaPvtd/2tYFkRQtXDWj1nackaV2JPXx3L0+Jvd8/qCJ2p+ML0/XVkJ2q+Mr+UVdpJK5w==}
     engines: {node: '>=12.0.0'}
 
+  html-parse-stringify@3.0.1:
+    resolution: {integrity: sha512-KknJ50kTInJ7qIScF3jeaFRpMpE8/lfiTdzf/twXyPBLAGrLRTmkz3AdTnKeh40X8k9L2fdYwEp/42WGXIRGcg==}
+
   html-url-attributes@3.0.1:
     resolution: {integrity: sha512-ol6UPyBWqsrO6EJySPz2O7ZSr856WDrEzM5zMqp+FJJLGMW35cLYmmZnl0vztAZxRUoNZJFTCohfjuIJ8I4QBQ==}
 
+  i18next@25.8.15:
+    resolution: {integrity: sha512-DW+vfwYtt+8lqpknhPGBfPL2P4SvtUv+KGDZAjfPrbnKAJkzVWGNRYw/rNkzxSzCBvnpiUnF5AgX7kL8hCg6uw==}
+    peerDependencies:
+      typescript: ^5
+    peerDependenciesMeta:
+      typescript:
+        optional: true
+
   inline-style-parser@0.2.7:
     resolution: {integrity: sha512-Nb2ctOyNR8DqQoR0OwRG95uNWIC0C1lCgf5Naz5H6Ji72KZ8OcFZLz2P5sNgwlyoJ8Yif11oMuYs5pBQa86csA==}
 
@@ -1972,6 +1993,22 @@ packages:
     peerDependencies:
       react: ^19.2.4
 
+  react-i18next@16.5.6:
+    resolution: {integrity: sha512-Ua7V2/efA88ido7KyK51fb8Ki8M/sRfW8LR/rZ/9ZKr2luhuTI7kwYZN5agT1rWG7aYm5G0RYE/6JR8KJoCMDw==}
+    peerDependencies:
+      i18next: '>= 25.6.2'
+      react: '>= 16.8.0'
+      react-dom: '*'
+      react-native: '*'
+      typescript: ^5
+    peerDependenciesMeta:
+      react-dom:
+        optional: true
+      react-native:
+        optional: true
+      typescript:
+        optional: true
+
   react-markdown@10.1.0:
     resolution: {integrity: sha512-qKxVopLT/TyA6BX3Ue5NwabOsAzm0Q7kAPwq6L+wWDwisYs7R8vZ0nRXqq6rkueboxpkjvLGU9fWifiX/ZZFxQ==}
     peerDependencies:
@@ -2204,6 +2241,10 @@ packages:
       yaml:
         optional: true
 
+  void-elements@3.1.0:
+    resolution: {integrity: sha512-Dhxzh5HZuiHQhbvTW9AMetFfBHDMYpo23Uo9btPXgdYP+3T5S+p+jgNy7spra+veYhBP2dCSgxR/i2Y02h5/6w==}
+    engines: {node: '>=0.10.0'}
+
   ws@8.19.0:
     resolution: {integrity: sha512-blAT2mjOEIi0ZzruJfIhb3nps74PRWTCz1IjglWEEpQl5XS/UNama6u2/rjFkDDouqr4L67ry+1aGIALViWjDg==}
     engines: {node: '>=10.0.0'}
@@ -2346,6 +2387,8 @@ snapshots:
       '@babel/core': 7.29.0
       '@babel/helper-plugin-utils': 7.28.6
 
+  '@babel/runtime@7.28.6': {}
+
   '@babel/template@7.28.6':
     dependencies:
       '@babel/code-frame': 7.29.0
@@ -3752,8 +3795,18 @@ snapshots:
 
   highlight.js@11.11.1: {}
 
+  html-parse-stringify@3.0.1:
+    dependencies:
+      void-elements: 3.1.0
+
   html-url-attributes@3.0.1: {}
 
+  i18next@25.8.15(typescript@5.7.3):
+    dependencies:
+      '@babel/runtime': 7.28.6
+    optionalDependencies:
+      typescript: 5.7.3
+
   inline-style-parser@0.2.7: {}
 
   is-alphabetical@2.0.1: {}
@@ -4299,6 +4352,17 @@ snapshots:
       react: 19.2.4
       scheduler: 0.27.0
 
+  react-i18next@16.5.6(i18next@25.8.15(typescript@5.7.3))(react-dom@19.2.4(react@19.2.4))(react@19.2.4)(typescript@5.7.3):
+    dependencies:
+      '@babel/runtime': 7.28.6
+      html-parse-stringify: 3.0.1
+      i18next: 25.8.15(typescript@5.7.3)
+      react: 19.2.4
+      use-sync-external-store: 1.6.0(react@19.2.4)
+    optionalDependencies:
+      react-dom: 19.2.4(react@19.2.4)
+      typescript: 5.7.3
+
   react-markdown@10.1.0(@types/react@19.2.14)(react@19.2.4):
     dependencies:
       '@types/hast': 3.0.4
@@ -4562,6 +4626,8 @@ snapshots:
       jiti: 2.6.1
       lightningcss: 1.31.1
 
+  void-elements@3.1.0: {}
+
   ws@8.19.0: {}
 
   yallist@3.1.1: {}
diff --git a/ui/web/src/api/ws-client.ts b/ui/web/src/api/ws-client.ts
index fe2054ed..07a5832b 100644
--- a/ui/web/src/api/ws-client.ts
+++ b/ui/web/src/api/ws-client.ts
@@ -197,6 +197,7 @@ export class WsClient {
         token: this.getToken(),
         user_id: this.getUserId(),
         sender_id: this.getSenderID(),
+        locale: localStorage.getItem("goclaw:language") || "en",
         protocolVersion: PROTOCOL_VERSION,
       });
       if (this.connectGeneration !== generation) return;
diff --git a/ui/web/src/components/chat/agent-selector.tsx b/ui/web/src/components/chat/agent-selector.tsx
index b40f85e5..f2d33db4 100644
--- a/ui/web/src/components/chat/agent-selector.tsx
+++ b/ui/web/src/components/chat/agent-selector.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Bot, ChevronDown } from "lucide-react";
 import { useHttp } from "@/hooks/use-ws";
 import { useAuthStore } from "@/stores/use-auth-store";
@@ -10,6 +11,7 @@ interface AgentSelectorProps {
 }
 
 export function AgentSelector({ value, onChange }: AgentSelectorProps) {
+  const { t } = useTranslation("common");
   const http = useHttp();
   const connected = useAuthStore((s) => s.connected);
   const [agents, setAgents] = useState<AgentData[]>([]);
@@ -37,7 +39,7 @@ export function AgentSelector({ value, onChange }: AgentSelectorProps) {
       >
         <Bot className="h-4 w-4 shrink-0 text-muted-foreground" />
         <span className="flex-1 truncate text-left">
-          {selected?.display_name ?? selected?.agent_key ?? (value || "Select agent")}
+          {selected?.display_name ?? selected?.agent_key ?? (value || t("selectAgent"))}
         </span>
         <ChevronDown className="h-4 w-4 shrink-0 text-muted-foreground" />
       </button>
@@ -48,7 +50,7 @@ export function AgentSelector({ value, onChange }: AgentSelectorProps) {
           <div className="absolute left-0 right-0 top-full z-50 mt-1 rounded-lg border bg-popover p-1 shadow-md">
             {agents.length === 0 && (
               <div className="px-3 py-2 text-sm text-muted-foreground">
-                No agents available
+                {t("noAgentsAvailable")}
               </div>
             )}
             {agents.map((agent) => (
@@ -68,7 +70,7 @@ export function AgentSelector({ value, onChange }: AgentSelectorProps) {
                   {agent.display_name || agent.agent_key}
                 </span>
                 {agent.is_default && (
-                  <span className="text-xs text-muted-foreground">default</span>
+                  <span className="text-xs text-muted-foreground">{t("default")}</span>
                 )}
               </button>
             ))}
diff --git a/ui/web/src/components/chat/chat-input.tsx b/ui/web/src/components/chat/chat-input.tsx
index ede4bb27..abea3e98 100644
--- a/ui/web/src/components/chat/chat-input.tsx
+++ b/ui/web/src/components/chat/chat-input.tsx
@@ -1,4 +1,5 @@
 import { useState, useRef, useCallback, type KeyboardEvent } from "react";
+import { useTranslation } from "react-i18next";
 import { Send, Square } from "lucide-react";
 import { Button } from "@/components/ui/button";
 
@@ -10,6 +11,7 @@ interface ChatInputProps {
 }
 
 export function ChatInput({ onSend, onAbort, isRunning, disabled }: ChatInputProps) {
+  const { t } = useTranslation("common");
   const [value, setValue] = useState("");
   const textareaRef = useRef<HTMLTextAreaElement>(null);
 
@@ -49,7 +51,7 @@ export function ChatInput({ onSend, onAbort, isRunning, disabled }: ChatInputPro
         onChange={(e) => setValue(e.target.value)}
         onKeyDown={handleKeyDown}
         onInput={handleInput}
-        placeholder="Send a message... (Shift+Enter for new line)"
+        placeholder={t("sendMessage")}
         disabled={disabled}
         rows={1}
         className="flex-1 resize-none rounded-lg border bg-background px-4 py-3 text-sm placeholder:text-muted-foreground focus:outline-none focus:ring-1 focus:ring-ring disabled:opacity-50"
@@ -59,7 +61,7 @@ export function ChatInput({ onSend, onAbort, isRunning, disabled }: ChatInputPro
           variant="destructive"
           size="icon-lg"
           onClick={onAbort}
-          title="Stop generation"
+          title={t("stopGeneration")}
         >
           <Square className="h-4 w-4" />
         </Button>
@@ -68,7 +70,7 @@ export function ChatInput({ onSend, onAbort, isRunning, disabled }: ChatInputPro
           size="icon-lg"
           onClick={handleSend}
           disabled={!value.trim() || disabled}
-          title="Send message"
+          title={t("sendMessageTitle")}
         >
           <Send className="h-4 w-4" />
         </Button>
diff --git a/ui/web/src/components/chat/rich-content.tsx b/ui/web/src/components/chat/rich-content.tsx
index 30d275d3..daa823c4 100644
--- a/ui/web/src/components/chat/rich-content.tsx
+++ b/ui/web/src/components/chat/rich-content.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Image,
   Video,
@@ -126,33 +127,26 @@ const mediaIcons: Record<string, typeof Image> = {
   animation: Video,
 };
 
-const mediaLabels: Record<string, string> = {
-  image: "Image",
-  video: "Video",
-  audio: "Audio",
-  voice: "Voice message",
-  document: "Document",
-  animation: "Animation",
-};
-
 function MediaBadge({ mediaType }: { mediaType: string }) {
+  const { t } = useTranslation("chat");
   const Icon = mediaIcons[mediaType] ?? FileText;
-  const label = mediaLabels[mediaType] ?? mediaType;
+  const label = t(`media.${mediaType}`, { defaultValue: mediaType });
 
   return (
     <span className="inline-flex items-center gap-1.5 rounded-md border border-blue-200 bg-blue-50 px-2 py-1 text-xs font-medium text-blue-700 dark:border-blue-800 dark:bg-blue-950 dark:text-blue-300">
       <Icon className="h-3.5 w-3.5" />
-      {label} attached
+      {label} {t("media.attached")}
     </span>
   );
 }
 
 function ForwardBadge({ from, date }: { from: string; date: string }) {
+  const { t } = useTranslation("chat");
   return (
     <div className="flex items-center gap-1.5 rounded-md border border-amber-200 bg-amber-50 px-2.5 py-1 text-xs text-amber-700 dark:border-amber-800 dark:bg-amber-950 dark:text-amber-300">
       <Forward className="h-3.5 w-3.5" />
       <span>
-        Forwarded from <span className="font-medium">{from}</span>
+        {t("forwardedFrom")} <span className="font-medium">{from}</span>
         {date && <span className="text-amber-600 dark:text-amber-400"> &middot; {date}</span>}
       </span>
     </div>
@@ -160,11 +154,12 @@ function ForwardBadge({ from, date }: { from: string; date: string }) {
 }
 
 function ReplyQuote({ sender, body }: { sender: string; body: string }) {
+  const { t } = useTranslation("chat");
   return (
     <div className="rounded-md border-l-2 border-muted-foreground/40 bg-muted/50 px-3 py-2">
       <div className="flex items-center gap-1.5 text-xs font-medium text-muted-foreground">
         <Reply className="h-3 w-3" />
-        Replying to {sender}
+        {t("replyingTo")} {sender}
       </div>
       <div className="mt-1 text-xs text-muted-foreground/80 line-clamp-3">{body}</div>
     </div>
diff --git a/ui/web/src/components/chat/session-switcher.tsx b/ui/web/src/components/chat/session-switcher.tsx
index 09a59f6a..3dfe5f24 100644
--- a/ui/web/src/components/chat/session-switcher.tsx
+++ b/ui/web/src/components/chat/session-switcher.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { MessageSquare } from "lucide-react";
 import { formatRelativeTime } from "@/lib/format";
 import { parseSessionKey } from "@/lib/session-key";
@@ -16,6 +17,7 @@ export function SessionSwitcher({
   onSelect,
   loading,
 }: SessionSwitcherProps) {
+  const { t } = useTranslation("common");
   if (sessions.length === 0 && loading) {
     return (
       <div className="space-y-2 p-2">
@@ -29,7 +31,7 @@ export function SessionSwitcher({
   if (sessions.length === 0) {
     return (
       <div className="px-4 py-8 text-center text-sm text-muted-foreground">
-        No sessions yet. Start a chat!
+        {t("noSessions")}
       </div>
     );
   }
@@ -56,7 +58,7 @@ export function SessionSwitcher({
             <div className="min-w-0 flex-1">
               <div className="truncate font-medium">{label}</div>
               <div className="flex items-center gap-2 text-xs text-muted-foreground">
-                <span>{session.messageCount} messages</span>
+                <span>{session.messageCount} {t("messages")}</span>
                 <span>{formatRelativeTime(session.updated)}</span>
               </div>
             </div>
diff --git a/ui/web/src/components/chat/thinking-block.tsx b/ui/web/src/components/chat/thinking-block.tsx
index 11b1749e..59f440ed 100644
--- a/ui/web/src/components/chat/thinking-block.tsx
+++ b/ui/web/src/components/chat/thinking-block.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { ChevronDown, ChevronRight, Brain } from "lucide-react";
 
 interface ThinkingBlockProps {
@@ -7,6 +8,7 @@ interface ThinkingBlockProps {
 }
 
 export function ThinkingBlock({ text, isStreaming = false }: ThinkingBlockProps) {
+  const { t } = useTranslation("common");
   const [expanded, setExpanded] = useState(isStreaming);
 
   return (
@@ -18,7 +20,7 @@ export function ThinkingBlock({ text, isStreaming = false }: ThinkingBlockProps)
       >
         <Brain className="h-3.5 w-3.5 shrink-0" />
         <span className="text-xs font-medium">
-          Thinking{isStreaming ? "..." : ""}
+          {isStreaming ? t("thinkingStreaming") : t("thinking")}
         </span>
         {expanded ? (
           <ChevronDown className="ml-auto h-3.5 w-3.5" />
diff --git a/ui/web/src/components/chat/tool-call-card.tsx b/ui/web/src/components/chat/tool-call-card.tsx
index d6b847db..5ab85ffb 100644
--- a/ui/web/src/components/chat/tool-call-card.tsx
+++ b/ui/web/src/components/chat/tool-call-card.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Wrench, Check, AlertTriangle, Loader2, ChevronDown, ChevronRight, Zap } from "lucide-react";
 import type { ToolStreamEntry } from "@/types/chat";
 
@@ -18,6 +19,7 @@ interface ToolCallCardProps {
 }
 
 export function ToolCallCard({ entry }: ToolCallCardProps) {
+  const { t } = useTranslation("common");
   const hasDetails = entry.arguments || entry.result;
   const hasError = entry.phase === "error" && !!entry.errorContent;
   const canExpand = hasDetails || hasError;
@@ -57,7 +59,7 @@ export function ToolCallCard({ entry }: ToolCallCardProps) {
           )}
           {entry.arguments && Object.keys(entry.arguments).length > 0 && (
             <div>
-              <div className="text-[10px] font-semibold uppercase text-muted-foreground mb-1">Arguments</div>
+              <div className="text-[10px] font-semibold uppercase text-muted-foreground mb-1">{t("toolArguments")}</div>
               <pre className="whitespace-pre-wrap text-xs font-mono bg-background rounded p-2 max-h-48 overflow-y-auto">
                 {JSON.stringify(entry.arguments, null, 2)}
               </pre>
@@ -65,7 +67,7 @@ export function ToolCallCard({ entry }: ToolCallCardProps) {
           )}
           {entry.result && (
             <div>
-              <div className="text-[10px] font-semibold uppercase text-muted-foreground mb-1">Result</div>
+              <div className="text-[10px] font-semibold uppercase text-muted-foreground mb-1">{t("toolResult")}</div>
               <pre className="whitespace-pre-wrap text-xs font-mono bg-background rounded p-2 max-h-48 overflow-y-auto">
                 {entry.result}
               </pre>
@@ -103,9 +105,10 @@ function ToolIcon({ phase, isSkill }: { phase: ToolStreamEntry["phase"]; isSkill
 }
 
 function PhaseLabel({ phase, isSkill }: { phase: ToolStreamEntry["phase"]; isSkill?: boolean }) {
+  const { t } = useTranslation("common");
   const labels: Record<string, string> = isSkill
-    ? { calling: "Activating...", completed: "Activated", error: "Failed" }
-    : { calling: "Running...", completed: "Done", error: "Failed" };
+    ? { calling: t("skillActivating"), completed: t("skillActivated"), error: t("toolFailed") }
+    : { calling: t("toolRunning"), completed: t("toolDone"), error: t("toolFailed") };
   const colors: Record<string, string> = {
     calling: "text-blue-500",
     completed: "text-green-500",
diff --git a/ui/web/src/components/layout/app-layout.tsx b/ui/web/src/components/layout/app-layout.tsx
index 163b070e..1e758370 100644
--- a/ui/web/src/components/layout/app-layout.tsx
+++ b/ui/web/src/components/layout/app-layout.tsx
@@ -1,5 +1,6 @@
 import { Outlet } from "react-router";
 import { WifiOff } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Sidebar } from "./sidebar";
 import { Topbar } from "./topbar";
 import { useUiStore } from "@/stores/use-ui-store";
@@ -8,6 +9,7 @@ import { useIsMobile } from "@/hooks/use-media-query";
 import { cn } from "@/lib/utils";
 
 export function AppLayout() {
+  const { t } = useTranslation("common");
   const sidebarCollapsed = useUiStore((s) => s.sidebarCollapsed);
   const mobileSidebarOpen = useUiStore((s) => s.mobileSidebarOpen);
   const setMobileSidebarOpen = useUiStore((s) => s.setMobileSidebarOpen);
@@ -43,7 +45,7 @@ export function AppLayout() {
         {!connected && (
           <div className="flex items-center gap-2 border-b border-destructive/30 bg-destructive/10 px-4 py-2 text-sm text-destructive">
             <WifiOff className="h-4 w-4 shrink-0" />
-            <span>Disconnected from gateway. Attempting to reconnect...</span>
+            <span>{t("disconnectedGateway")}</span>
           </div>
         )}
         <main className="flex-1 overflow-y-auto">
diff --git a/ui/web/src/components/layout/connection-status.tsx b/ui/web/src/components/layout/connection-status.tsx
index 123ef00f..d5447014 100644
--- a/ui/web/src/components/layout/connection-status.tsx
+++ b/ui/web/src/components/layout/connection-status.tsx
@@ -1,7 +1,9 @@
+import { useTranslation } from "react-i18next";
 import { useAuthStore } from "@/stores/use-auth-store";
 import { cn } from "@/lib/utils";
 
 export function ConnectionStatus() {
+  const { t } = useTranslation("common");
   const connected = useAuthStore((s) => s.connected);
 
   return (
@@ -12,7 +14,7 @@ export function ConnectionStatus() {
           connected ? "bg-green-500" : "bg-red-500",
         )}
       />
-      <span>{connected ? "Connected" : "Disconnected"}</span>
+      <span>{connected ? t("connected") : t("disconnected")}</span>
     </div>
   );
 }
diff --git a/ui/web/src/components/layout/sidebar.tsx b/ui/web/src/components/layout/sidebar.tsx
index e114784d..4896797e 100644
--- a/ui/web/src/components/layout/sidebar.tsx
+++ b/ui/web/src/components/layout/sidebar.tsx
@@ -24,6 +24,7 @@ import {
   Inbox,
   Brain,
 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { SidebarGroup } from "./sidebar-group";
 import { SidebarItem } from "./sidebar-item";
 import { ConnectionStatus } from "./connection-status";
@@ -37,6 +38,7 @@ interface SidebarProps {
 }
 
 export function Sidebar({ collapsed, onNavItemClick }: SidebarProps) {
+  const { t } = useTranslation("sidebar");
   const { pendingCount } = usePendingPairingsCount();
 
   return (
@@ -66,40 +68,40 @@ export function Sidebar({ collapsed, onNavItemClick }: SidebarProps) {
 
       {/* Nav items */}
       <nav className="flex-1 space-y-4 overflow-y-auto px-2 py-4">
-        <SidebarGroup label="Core" collapsed={collapsed}>
-          <SidebarItem to={ROUTES.OVERVIEW} icon={LayoutDashboard} label="Overview" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.CHAT} icon={MessageSquare} label="Chat" collapsed={collapsed} />
+        <SidebarGroup label={t("groups.core")} collapsed={collapsed}>
+          <SidebarItem to={ROUTES.OVERVIEW} icon={LayoutDashboard} label={t("nav.overview")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.CHAT} icon={MessageSquare} label={t("nav.chat")} collapsed={collapsed} />
         </SidebarGroup>
 
-        <SidebarGroup label="Management" collapsed={collapsed}>
-          <SidebarItem to={ROUTES.AGENTS} icon={Bot} label="Agents" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.TEAMS} icon={Users} label="Agent Teams" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.SESSIONS} icon={History} label="Sessions" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.PENDING_MESSAGES} icon={Inbox} label="Pending Messages" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.CHANNELS} icon={Radio} label="Channels" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.SKILLS} icon={Zap} label="Skills" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.CRON} icon={Clock} label="Cron" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.CUSTOM_TOOLS} icon={Wrench} label="Custom Tools" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.BUILTIN_TOOLS} icon={Package} label="Built-in Tools" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.MCP} icon={Plug} label="MCP Servers" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.MEMORY} icon={Brain} label="Memory" collapsed={collapsed} />
+        <SidebarGroup label={t("groups.management")} collapsed={collapsed}>
+          <SidebarItem to={ROUTES.AGENTS} icon={Bot} label={t("nav.agents")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.TEAMS} icon={Users} label={t("nav.agentTeams")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.SESSIONS} icon={History} label={t("nav.sessions")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.PENDING_MESSAGES} icon={Inbox} label={t("nav.pendingMessages")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.CHANNELS} icon={Radio} label={t("nav.channels")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.SKILLS} icon={Zap} label={t("nav.skills")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.CRON} icon={Clock} label={t("nav.cron")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.CUSTOM_TOOLS} icon={Wrench} label={t("nav.customTools")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.BUILTIN_TOOLS} icon={Package} label={t("nav.builtinTools")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.MCP} icon={Plug} label={t("nav.mcpServers")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.MEMORY} icon={Brain} label={t("nav.memory")} collapsed={collapsed} />
         </SidebarGroup>
 
-        <SidebarGroup label="Monitoring" collapsed={collapsed}>
-          <SidebarItem to={ROUTES.TRACES} icon={Activity} label="Traces" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.EVENTS} icon={Radar} label="Realtime Events" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.DELEGATIONS} icon={ArrowRightLeft} label="Delegations" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.USAGE} icon={BarChart3} label="Usage" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.LOGS} icon={Terminal} label="Logs" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.STORAGE} icon={HardDrive} label="Storage" collapsed={collapsed} />
+        <SidebarGroup label={t("groups.monitoring")} collapsed={collapsed}>
+          <SidebarItem to={ROUTES.TRACES} icon={Activity} label={t("nav.traces")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.EVENTS} icon={Radar} label={t("nav.realtimeEvents")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.DELEGATIONS} icon={ArrowRightLeft} label={t("nav.delegations")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.USAGE} icon={BarChart3} label={t("nav.usage")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.LOGS} icon={Terminal} label={t("nav.logs")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.STORAGE} icon={HardDrive} label={t("nav.storage")} collapsed={collapsed} />
         </SidebarGroup>
 
-        <SidebarGroup label="System" collapsed={collapsed}>
-          <SidebarItem to={ROUTES.PROVIDERS} icon={Cpu} label="Providers" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.CONFIG} icon={Settings} label="Config" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.APPROVALS} icon={ShieldCheck} label="Approvals" collapsed={collapsed} />
-          <SidebarItem to={ROUTES.NODES} icon={Link} label="Nodes" collapsed={collapsed} badge={pendingCount} />
-          <SidebarItem to={ROUTES.TTS} icon={Volume2} label="TTS" collapsed={collapsed} />
+        <SidebarGroup label={t("groups.system")} collapsed={collapsed}>
+          <SidebarItem to={ROUTES.PROVIDERS} icon={Cpu} label={t("nav.providers")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.CONFIG} icon={Settings} label={t("nav.config")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.APPROVALS} icon={ShieldCheck} label={t("nav.approvals")} collapsed={collapsed} />
+          <SidebarItem to={ROUTES.NODES} icon={Link} label={t("nav.nodes")} collapsed={collapsed} badge={pendingCount} />
+          <SidebarItem to={ROUTES.TTS} icon={Volume2} label={t("nav.tts")} collapsed={collapsed} />
         </SidebarGroup>
       </nav>
 
diff --git a/ui/web/src/components/layout/topbar.tsx b/ui/web/src/components/layout/topbar.tsx
index f5ec3c2a..d2117bd8 100644
--- a/ui/web/src/components/layout/topbar.tsx
+++ b/ui/web/src/components/layout/topbar.tsx
@@ -1,14 +1,18 @@
-import { Moon, Sun, PanelLeftClose, PanelLeftOpen, Menu, LogOut, Bell } from "lucide-react";
+import { Moon, Sun, PanelLeftClose, PanelLeftOpen, Menu, LogOut, Bell, Globe } from "lucide-react";
 import { useNavigate } from "react-router";
+import { useTranslation } from "react-i18next";
 import { useUiStore } from "@/stores/use-ui-store";
 import { useAuthStore } from "@/stores/use-auth-store";
 import { useIsMobile } from "@/hooks/use-media-query";
 import { usePendingPairingsCount } from "@/hooks/use-pending-pairings-count";
-import { ROUTES } from "@/lib/constants";
+import { ROUTES, SUPPORTED_LANGUAGES, LANGUAGE_LABELS, type Language } from "@/lib/constants";
 
 export function Topbar() {
+  const { t } = useTranslation("topbar");
   const theme = useUiStore((s) => s.theme);
   const setTheme = useUiStore((s) => s.setTheme);
+  const language = useUiStore((s) => s.language);
+  const setLanguage = useUiStore((s) => s.setLanguage);
   const sidebarCollapsed = useUiStore((s) => s.sidebarCollapsed);
   const toggleSidebar = useUiStore((s) => s.toggleSidebar);
   const setMobileSidebarOpen = useUiStore((s) => s.setMobileSidebarOpen);
@@ -24,13 +28,19 @@ export function Topbar() {
     ? () => setMobileSidebarOpen(true)
     : toggleSidebar;
 
+  const cycleLanguage = () => {
+    const idx = SUPPORTED_LANGUAGES.indexOf(language);
+    const next = SUPPORTED_LANGUAGES[(idx + 1) % SUPPORTED_LANGUAGES.length] as Language;
+    setLanguage(next);
+  };
+
   return (
     <header className="flex h-14 items-center justify-between border-b bg-background px-4">
       <div className="flex items-center gap-2">
         <button
           onClick={handleSidebarToggle}
           className="cursor-pointer rounded-md p-2 text-muted-foreground hover:bg-accent hover:text-accent-foreground"
-          title={isMobile ? "Open menu" : sidebarCollapsed ? "Expand sidebar" : "Collapse sidebar"}
+          title={isMobile ? t("openMenu") : sidebarCollapsed ? t("expandSidebar") : t("collapseSidebar")}
         >
           {isMobile ? (
             <Menu className="h-4 w-4" />
@@ -50,7 +60,7 @@ export function Topbar() {
         <button
           onClick={() => navigate(ROUTES.NODES)}
           className="relative cursor-pointer rounded-md p-2 text-muted-foreground hover:bg-accent hover:text-accent-foreground"
-          title={pendingCount > 0 ? `${pendingCount} pending pairing request${pendingCount > 1 ? "s" : ""}` : "Pairing requests"}
+          title={pendingCount > 0 ? t("pendingPairing", { count: pendingCount }) : t("pairingRequests")}
         >
           <Bell className="h-4 w-4" />
           {pendingCount > 0 && (
@@ -58,10 +68,19 @@ export function Topbar() {
           )}
         </button>
 
+        <button
+          onClick={cycleLanguage}
+          className="cursor-pointer rounded-md p-2 text-muted-foreground hover:bg-accent hover:text-accent-foreground flex items-center gap-1"
+          title={t("language")}
+        >
+          <Globe className="h-4 w-4" />
+          <span className="text-xs">{LANGUAGE_LABELS[language]}</span>
+        </button>
+
         <button
           onClick={() => setTheme(isDark ? "light" : "dark")}
           className="cursor-pointer rounded-md p-2 text-muted-foreground hover:bg-accent hover:text-accent-foreground"
-          title="Toggle theme"
+          title={t("toggleTheme")}
         >
           {isDark ? <Sun className="h-4 w-4" /> : <Moon className="h-4 w-4" />}
         </button>
@@ -69,7 +88,7 @@ export function Topbar() {
         <button
           onClick={logout}
           className="cursor-pointer rounded-md p-2 text-muted-foreground hover:bg-accent hover:text-accent-foreground"
-          title="Logout"
+          title={t("logout")}
         >
           <LogOut className="h-4 w-4" />
         </button>
diff --git a/ui/web/src/components/shared/confirm-delete-dialog.tsx b/ui/web/src/components/shared/confirm-delete-dialog.tsx
index 0d1a3346..8d998542 100644
--- a/ui/web/src/components/shared/confirm-delete-dialog.tsx
+++ b/ui/web/src/components/shared/confirm-delete-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -27,10 +28,11 @@ export function ConfirmDeleteDialog({
   title,
   description,
   confirmValue,
-  confirmLabel = "Delete",
+  confirmLabel,
   onConfirm,
   loading,
 }: ConfirmDeleteDialogProps) {
+  const { t } = useTranslation("common");
   const [inputValue, setInputValue] = useState("");
 
   useEffect(() => {
@@ -48,7 +50,7 @@ export function ConfirmDeleteDialog({
         </DialogHeader>
         <div className="py-2">
           <p className="mb-2 text-sm text-muted-foreground">
-            Type <span className="font-semibold text-foreground">{confirmValue}</span> to confirm.
+            {t("typeToConfirmPrefix")} <span className="font-semibold text-foreground">{confirmValue}</span> {t("typeToConfirmSuffix")}
           </p>
           <Input
             value={inputValue}
@@ -59,14 +61,14 @@ export function ConfirmDeleteDialog({
         </div>
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>
-            Cancel
+            {t("cancel")}
           </Button>
           <Button
             variant="destructive"
             onClick={onConfirm}
             disabled={!isMatch || loading}
           >
-            {loading ? "..." : confirmLabel}
+            {loading ? "..." : (confirmLabel ?? t("delete"))}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/components/shared/confirm-dialog.tsx b/ui/web/src/components/shared/confirm-dialog.tsx
index 5904d31c..be593184 100644
--- a/ui/web/src/components/shared/confirm-dialog.tsx
+++ b/ui/web/src/components/shared/confirm-dialog.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -24,11 +25,12 @@ export function ConfirmDialog({
   onOpenChange,
   title,
   description,
-  confirmLabel = "Confirm",
+  confirmLabel,
   variant = "default",
   onConfirm,
   loading,
 }: ConfirmDialogProps) {
+  const { t } = useTranslation("common");
   return (
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent>
@@ -38,10 +40,10 @@ export function ConfirmDialog({
         </DialogHeader>
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>
-            Cancel
+            {t("cancel")}
           </Button>
           <Button variant={variant} onClick={onConfirm} disabled={loading}>
-            {loading ? "..." : confirmLabel}
+            {loading ? "..." : (confirmLabel ?? t("confirm"))}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/components/shared/file-browser.tsx b/ui/web/src/components/shared/file-browser.tsx
index a0f990c6..cf3d2b62 100644
--- a/ui/web/src/components/shared/file-browser.tsx
+++ b/ui/web/src/components/shared/file-browser.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback, useRef } from "react";
+import { useTranslation } from "react-i18next";
 import { formatSize, type TreeNode } from "@/lib/file-helpers";
 import { FileTreePanel } from "@/components/shared/file-tree";
 import { FileContentPanel } from "@/components/shared/file-viewers";
@@ -33,6 +34,7 @@ export function FileBrowser({
   showSize?: boolean;
 }) {
   const isMobile = useIsMobile();
+  const { t } = useTranslation("common");
   const containerRef = useRef<HTMLDivElement>(null);
   const [treeWidth, setTreeWidth] = useState(220);
   const [mobileShowTree, setMobileShowTree] = useState(true);
@@ -82,7 +84,7 @@ export function FileBrowser({
                 onClick={() => setMobileShowTree(true)}
                 className="text-primary hover:underline cursor-pointer shrink-0"
               >
-                &larr; Files
+                &larr; {t("filesBack")}
               </button>
               {fileContent && (
                 <>
diff --git a/ui/web/src/components/shared/file-tree.tsx b/ui/web/src/components/shared/file-tree.tsx
index 65e7d442..8c1607a7 100644
--- a/ui/web/src/components/shared/file-tree.tsx
+++ b/ui/web/src/components/shared/file-tree.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Folder,
   FolderOpen,
@@ -119,6 +120,7 @@ export function FileTreePanel({
   onDelete?: (path: string, isDir: boolean) => void;
   showSize?: boolean;
 }) {
+  const { t } = useTranslation("common");
   if (filesLoading) {
     return (
       <div className="flex items-center justify-center py-8">
@@ -127,7 +129,7 @@ export function FileTreePanel({
     );
   }
   if (tree.length === 0) {
-    return <p className="px-3 py-4 text-sm text-muted-foreground">No files found.</p>;
+    return <p className="px-3 py-4 text-sm text-muted-foreground">{t("noFiles")}</p>;
   }
   return (
     <>
diff --git a/ui/web/src/components/shared/file-viewers.tsx b/ui/web/src/components/shared/file-viewers.tsx
index daa121be..e838898c 100644
--- a/ui/web/src/components/shared/file-viewers.tsx
+++ b/ui/web/src/components/shared/file-viewers.tsx
@@ -1,4 +1,5 @@
 import { useMemo, useRef } from "react";
+import { useTranslation } from "react-i18next";
 import { Check, Copy, Loader2 } from "lucide-react";
 import { MarkdownRenderer } from "@/components/shared/markdown-renderer";
 import { useClipboard } from "@/hooks/use-clipboard";
@@ -162,6 +163,7 @@ export function FileContentPanel({
   fileContent: { content: string; path: string; size: number } | null;
   contentLoading: boolean;
 }) {
+  const { t } = useTranslation("common");
   if (contentLoading) {
     return (
       <div className="flex items-center justify-center py-8">
@@ -174,7 +176,7 @@ export function FileContentPanel({
   }
   return (
     <div className="flex items-center justify-center py-8 text-sm text-muted-foreground">
-      Select a file to view its content
+      {t("selectFileToView")}
     </div>
   );
 }
diff --git a/ui/web/src/components/shared/pagination.tsx b/ui/web/src/components/shared/pagination.tsx
index 6337bfd4..7311079a 100644
--- a/ui/web/src/components/shared/pagination.tsx
+++ b/ui/web/src/components/shared/pagination.tsx
@@ -1,4 +1,5 @@
 import { ChevronLeft, ChevronRight } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import {
   Select,
@@ -29,16 +30,17 @@ export function Pagination({
   onPageSizeChange,
   pageSizes = PAGE_SIZES,
 }: PaginationProps) {
+  const { t } = useTranslation("common");
   if (total === 0) return null;
 
   return (
     <div className="flex flex-col items-center gap-2 border-t px-4 py-3 sm:flex-row sm:justify-between">
       <div className="text-sm text-muted-foreground">
-        {total} {total === 1 ? "item" : "items"}
+        {total} {t("items")}
       </div>
       <div className="flex items-center gap-2 sm:gap-4">
         <div className="flex items-center gap-2">
-          <span className="text-sm text-muted-foreground">Rows</span>
+          <span className="text-sm text-muted-foreground">{t("rows")}</span>
           <Select
             value={String(pageSize)}
             onValueChange={(v) => onPageSizeChange(Number(v))}
@@ -56,7 +58,7 @@ export function Pagination({
           </Select>
         </div>
         <span className="text-sm text-muted-foreground">
-          Page {page} of {totalPages}
+          {t("pageOf", { page, totalPages })}
         </span>
         <div className="flex items-center gap-1">
           <Button
diff --git a/ui/web/src/components/shared/provider-model-select.tsx b/ui/web/src/components/shared/provider-model-select.tsx
index 8737bd59..2dd67b52 100644
--- a/ui/web/src/components/shared/provider-model-select.tsx
+++ b/ui/web/src/components/shared/provider-model-select.tsx
@@ -1,4 +1,5 @@
 import { useMemo, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Combobox } from "@/components/ui/combobox";
@@ -40,17 +41,18 @@ export function ProviderModelSelect({
   onProviderChange,
   model,
   onModelChange,
-  providerTip = "LLM provider name. Must match a configured provider.",
-  modelTip = "Model ID to use.",
-  providerLabel = "Provider",
-  modelLabel = "Model",
-  providerPlaceholder = "Select provider",
-  modelPlaceholder = "Enter or select model",
+  providerTip,
+  modelTip,
+  providerLabel,
+  modelLabel,
+  providerPlaceholder,
+  modelPlaceholder,
   showVerify,
   savedProvider,
   savedModel,
   onSaveBlockedChange,
 }: ProviderModelSelectProps) {
+  const { t } = useTranslation("common");
   const { providers } = useProviders();
   const enabledProviders = providers.filter((p) => p.enabled);
 
@@ -94,11 +96,11 @@ export function ProviderModelSelect({
   return (
     <div className="grid grid-cols-2 gap-4">
       <div className="grid gap-1.5">
-        <InfoLabel tip={providerTip}>{providerLabel}</InfoLabel>
+        <InfoLabel tip={providerTip ?? t("providerTip")}>{providerLabel ?? t("provider")}</InfoLabel>
         {enabledProviders.length > 0 ? (
           <Select value={provider} onValueChange={handleProviderChange}>
             <SelectTrigger>
-              <SelectValue placeholder={providerPlaceholder} />
+              <SelectValue placeholder={providerPlaceholder ?? t("selectProvider")} />
             </SelectTrigger>
             <SelectContent>
               {enabledProviders.map((p) => (
@@ -112,19 +114,19 @@ export function ProviderModelSelect({
           <Input
             value={provider}
             onChange={(e) => handleProviderChange(e.target.value)}
-            placeholder="No providers configured"
+            placeholder={t("noProvidersConfigured")}
           />
         )}
       </div>
       <div className="grid gap-1.5">
-        <InfoLabel tip={modelTip}>{modelLabel}</InfoLabel>
+        <InfoLabel tip={modelTip ?? t("modelTip")}>{modelLabel ?? t("model")}</InfoLabel>
         <div className="flex gap-2">
           <div className="flex-1">
             <Combobox
               value={model}
               onChange={onModelChange}
               options={models.map((m) => ({ value: m.id, label: m.name }))}
-              placeholder={modelsLoading ? "Loading models..." : modelPlaceholder}
+              placeholder={modelsLoading ? t("loadingModels") : (modelPlaceholder ?? t("enterOrSelectModel"))}
             />
           </div>
           {shouldShowVerify && (
@@ -136,13 +138,13 @@ export function ProviderModelSelect({
               disabled={!selectedProviderId || !model.trim() || verifying}
               onClick={handleVerify}
             >
-              {verifying ? "..." : "Check"}
+              {verifying ? "..." : t("check")}
             </Button>
           )}
         </div>
         {shouldShowVerify && verifyResult && (
           <p className={`text-xs ${verifyResult.valid ? "text-success" : "text-destructive"}`}>
-            {verifyResult.valid ? "Model verified" : verifyResult.error || "Verification failed"}
+            {verifyResult.valid ? t("modelVerified") : verifyResult.error || t("verificationFailed")}
           </p>
         )}
       </div>
diff --git a/ui/web/src/components/shared/search-input.tsx b/ui/web/src/components/shared/search-input.tsx
index fb4b7e33..c35cd781 100644
--- a/ui/web/src/components/shared/search-input.tsx
+++ b/ui/web/src/components/shared/search-input.tsx
@@ -1,4 +1,5 @@
 import { Search } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { useDebounce } from "@/hooks/use-debounce";
 import { useState, useEffect } from "react";
@@ -14,10 +15,11 @@ interface SearchInputProps {
 export function SearchInput({
   value,
   onChange,
-  placeholder = "Search...",
+  placeholder,
   className,
   delay = 300,
 }: SearchInputProps) {
+  const { t } = useTranslation("common");
   const [local, setLocal] = useState(value);
   const debounced = useDebounce(local, delay);
 
@@ -35,7 +37,7 @@ export function SearchInput({
       <Input
         value={local}
         onChange={(e) => setLocal(e.target.value)}
-        placeholder={placeholder}
+        placeholder={placeholder ?? t("searchPlaceholder")}
         className="pl-9"
       />
     </div>
diff --git a/ui/web/src/components/shared/tag-input.tsx b/ui/web/src/components/shared/tag-input.tsx
index 1e20ba0f..4c00d1c0 100644
--- a/ui/web/src/components/shared/tag-input.tsx
+++ b/ui/web/src/components/shared/tag-input.tsx
@@ -1,4 +1,5 @@
 import { useState, useRef } from "react";
+import { useTranslation } from "react-i18next";
 import { X } from "lucide-react";
 import { cn } from "@/lib/utils";
 
@@ -12,9 +13,10 @@ interface TagInputProps {
 export function TagInput({
   value,
   onChange,
-  placeholder = "Type and press Enter...",
+  placeholder,
   className,
 }: TagInputProps) {
+  const { t } = useTranslation("common");
   const [input, setInput] = useState("");
   const inputRef = useRef<HTMLInputElement>(null);
 
@@ -70,7 +72,7 @@ export function TagInput({
         onChange={(e) => setInput(e.target.value)}
         onKeyDown={handleKeyDown}
         onBlur={() => { if (input.trim()) addTag(input); }}
-        placeholder={value.length === 0 ? placeholder : ""}
+        placeholder={value.length === 0 ? (placeholder ?? t("typeAndPressEnter")) : ""}
         className="placeholder:text-muted-foreground min-w-[80px] flex-1 bg-transparent py-0.5 text-sm outline-none"
       />
     </div>
diff --git a/ui/web/src/components/shared/tool-name-select.tsx b/ui/web/src/components/shared/tool-name-select.tsx
index 68168484..ca558b16 100644
--- a/ui/web/src/components/shared/tool-name-select.tsx
+++ b/ui/web/src/components/shared/tool-name-select.tsx
@@ -1,4 +1,5 @@
 import { useMemo, useState, useRef, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { X, ChevronDownIcon } from "lucide-react";
 import { cn } from "@/lib/utils";
 import { useBuiltinTools } from "@/pages/builtin-tools/hooks/use-builtin-tools";
@@ -20,9 +21,10 @@ interface ToolOption {
 export function ToolNameSelect({
   value,
   onChange,
-  placeholder = "Select or type tool names...",
+  placeholder,
   className,
 }: ToolNameSelectProps) {
+  const { t } = useTranslation("common");
   const { tools: builtinTools } = useBuiltinTools();
   const { tools: customTools } = useCustomTools();
   const [open, setOpen] = useState(false);
@@ -127,7 +129,7 @@ export function ToolNameSelect({
           }}
           onFocus={() => setOpen(true)}
           onKeyDown={handleKeyDown}
-          placeholder={value.length === 0 ? placeholder : ""}
+          placeholder={value.length === 0 ? (placeholder ?? t("selectOrTypeTools")) : ""}
           className="placeholder:text-muted-foreground min-w-[80px] flex-1 bg-transparent py-0.5 text-sm outline-none"
         />
         <ChevronDownIcon
@@ -140,7 +142,7 @@ export function ToolNameSelect({
           {grouped.builtin.length > 0 && (
             <>
               <div className="text-muted-foreground px-2 py-1 text-[10px] font-semibold uppercase tracking-wider">
-                Built-in
+                {t("builtinTools")}
               </div>
               {grouped.builtin.map((t) => (
                 <button
@@ -159,7 +161,7 @@ export function ToolNameSelect({
           {grouped.custom.length > 0 && (
             <>
               <div className="text-muted-foreground mt-1 px-2 py-1 text-[10px] font-semibold uppercase tracking-wider">
-                Custom
+                {t("customTools")}
               </div>
               {grouped.custom.map((t) => (
                 <button
diff --git a/ui/web/src/i18n/index.ts b/ui/web/src/i18n/index.ts
new file mode 100644
index 00000000..d8f6d7cd
--- /dev/null
+++ b/ui/web/src/i18n/index.ts
@@ -0,0 +1,161 @@
+import i18n from "i18next";
+import { initReactI18next } from "react-i18next";
+
+// --- EN namespaces ---
+import enCommon from "./locales/en/common.json";
+import enSidebar from "./locales/en/sidebar.json";
+import enTopbar from "./locales/en/topbar.json";
+import enLogin from "./locales/en/login.json";
+import enOverview from "./locales/en/overview.json";
+import enChat from "./locales/en/chat.json";
+import enAgents from "./locales/en/agents.json";
+import enTeams from "./locales/en/teams.json";
+import enSessions from "./locales/en/sessions.json";
+import enSkills from "./locales/en/skills.json";
+import enCron from "./locales/en/cron.json";
+import enConfig from "./locales/en/config.json";
+import enChannels from "./locales/en/channels.json";
+import enProviders from "./locales/en/providers.json";
+import enTraces from "./locales/en/traces.json";
+import enEvents from "./locales/en/events.json";
+import enDelegations from "./locales/en/delegations.json";
+import enUsage from "./locales/en/usage.json";
+import enApprovals from "./locales/en/approvals.json";
+import enNodes from "./locales/en/nodes.json";
+import enLogs from "./locales/en/logs.json";
+import enTools from "./locales/en/tools.json";
+import enMcp from "./locales/en/mcp.json";
+import enTts from "./locales/en/tts.json";
+import enSetup from "./locales/en/setup.json";
+import enMemory from "./locales/en/memory.json";
+import enStorage from "./locales/en/storage.json";
+import enPendingMessages from "./locales/en/pending-messages.json";
+
+// --- VI namespaces ---
+import viCommon from "./locales/vi/common.json";
+import viSidebar from "./locales/vi/sidebar.json";
+import viTopbar from "./locales/vi/topbar.json";
+import viLogin from "./locales/vi/login.json";
+import viOverview from "./locales/vi/overview.json";
+import viChat from "./locales/vi/chat.json";
+import viAgents from "./locales/vi/agents.json";
+import viTeams from "./locales/vi/teams.json";
+import viSessions from "./locales/vi/sessions.json";
+import viSkills from "./locales/vi/skills.json";
+import viCron from "./locales/vi/cron.json";
+import viConfig from "./locales/vi/config.json";
+import viChannels from "./locales/vi/channels.json";
+import viProviders from "./locales/vi/providers.json";
+import viTraces from "./locales/vi/traces.json";
+import viEvents from "./locales/vi/events.json";
+import viDelegations from "./locales/vi/delegations.json";
+import viUsage from "./locales/vi/usage.json";
+import viApprovals from "./locales/vi/approvals.json";
+import viNodes from "./locales/vi/nodes.json";
+import viLogs from "./locales/vi/logs.json";
+import viTools from "./locales/vi/tools.json";
+import viMcp from "./locales/vi/mcp.json";
+import viTts from "./locales/vi/tts.json";
+import viSetup from "./locales/vi/setup.json";
+import viMemory from "./locales/vi/memory.json";
+import viStorage from "./locales/vi/storage.json";
+import viPendingMessages from "./locales/vi/pending-messages.json";
+
+// --- ZH namespaces ---
+import zhCommon from "./locales/zh/common.json";
+import zhSidebar from "./locales/zh/sidebar.json";
+import zhTopbar from "./locales/zh/topbar.json";
+import zhLogin from "./locales/zh/login.json";
+import zhOverview from "./locales/zh/overview.json";
+import zhChat from "./locales/zh/chat.json";
+import zhAgents from "./locales/zh/agents.json";
+import zhTeams from "./locales/zh/teams.json";
+import zhSessions from "./locales/zh/sessions.json";
+import zhSkills from "./locales/zh/skills.json";
+import zhCron from "./locales/zh/cron.json";
+import zhConfig from "./locales/zh/config.json";
+import zhChannels from "./locales/zh/channels.json";
+import zhProviders from "./locales/zh/providers.json";
+import zhTraces from "./locales/zh/traces.json";
+import zhEvents from "./locales/zh/events.json";
+import zhDelegations from "./locales/zh/delegations.json";
+import zhUsage from "./locales/zh/usage.json";
+import zhApprovals from "./locales/zh/approvals.json";
+import zhNodes from "./locales/zh/nodes.json";
+import zhLogs from "./locales/zh/logs.json";
+import zhTools from "./locales/zh/tools.json";
+import zhMcp from "./locales/zh/mcp.json";
+import zhTts from "./locales/zh/tts.json";
+import zhSetup from "./locales/zh/setup.json";
+import zhMemory from "./locales/zh/memory.json";
+import zhStorage from "./locales/zh/storage.json";
+import zhPendingMessages from "./locales/zh/pending-messages.json";
+
+const STORAGE_KEY = "goclaw:language";
+
+function getInitialLanguage(): string {
+  const stored = localStorage.getItem(STORAGE_KEY);
+  if (stored === "en" || stored === "vi" || stored === "zh") return stored;
+  const lang = navigator.language.toLowerCase();
+  if (lang.startsWith("vi")) return "vi";
+  if (lang.startsWith("zh")) return "zh";
+  return "en";
+}
+
+const ns = [
+  "common", "sidebar", "topbar", "login", "overview", "chat",
+  "agents", "teams", "sessions", "skills", "cron", "config",
+  "channels", "providers", "traces", "events", "delegations",
+  "usage", "approvals", "nodes", "logs", "tools", "mcp", "tts",
+  "setup", "memory", "storage", "pending-messages",
+] as const;
+
+i18n.use(initReactI18next).init({
+  resources: {
+    en: {
+      common: enCommon, sidebar: enSidebar, topbar: enTopbar, login: enLogin,
+      overview: enOverview, chat: enChat, agents: enAgents, teams: enTeams,
+      sessions: enSessions, skills: enSkills, cron: enCron, config: enConfig,
+      channels: enChannels, providers: enProviders, traces: enTraces,
+      events: enEvents, delegations: enDelegations, usage: enUsage,
+      approvals: enApprovals, nodes: enNodes, logs: enLogs, tools: enTools,
+      mcp: enMcp, tts: enTts, setup: enSetup, memory: enMemory, storage: enStorage,
+      "pending-messages": enPendingMessages,
+    },
+    vi: {
+      common: viCommon, sidebar: viSidebar, topbar: viTopbar, login: viLogin,
+      overview: viOverview, chat: viChat, agents: viAgents, teams: viTeams,
+      sessions: viSessions, skills: viSkills, cron: viCron, config: viConfig,
+      channels: viChannels, providers: viProviders, traces: viTraces,
+      events: viEvents, delegations: viDelegations, usage: viUsage,
+      approvals: viApprovals, nodes: viNodes, logs: viLogs, tools: viTools,
+      mcp: viMcp, tts: viTts, setup: viSetup, memory: viMemory, storage: viStorage,
+      "pending-messages": viPendingMessages,
+    },
+    zh: {
+      common: zhCommon, sidebar: zhSidebar, topbar: zhTopbar, login: zhLogin,
+      overview: zhOverview, chat: zhChat, agents: zhAgents, teams: zhTeams,
+      sessions: zhSessions, skills: zhSkills, cron: zhCron, config: zhConfig,
+      channels: zhChannels, providers: zhProviders, traces: zhTraces,
+      events: zhEvents, delegations: zhDelegations, usage: zhUsage,
+      approvals: zhApprovals, nodes: zhNodes, logs: zhLogs, tools: zhTools,
+      mcp: zhMcp, tts: zhTts, setup: zhSetup, memory: zhMemory, storage: zhStorage,
+      "pending-messages": zhPendingMessages,
+    },
+  },
+  ns: [...ns],
+  defaultNS: "common",
+  lng: getInitialLanguage(),
+  fallbackLng: "en",
+  interpolation: { escapeValue: false },
+  missingKeyHandler: import.meta.env.DEV
+    ? (_lngs, _ns, key) => console.warn(`[i18n] missing: ${key}`)
+    : undefined,
+});
+
+i18n.on("languageChanged", (lng) => {
+  localStorage.setItem(STORAGE_KEY, lng);
+  document.documentElement.lang = lng;
+});
+
+export default i18n;
diff --git a/ui/web/src/i18n/locales/en/agents.json b/ui/web/src/i18n/locales/en/agents.json
new file mode 100644
index 00000000..bf3e257b
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/agents.json
@@ -0,0 +1,342 @@
+{
+  "title": "Agents",
+  "description": "Manage your AI agents",
+  "createAgent": "Create Agent",
+  "searchPlaceholder": "Search agents...",
+  "emptyTitle": "No agents yet",
+  "emptyDescription": "Create your first agent to get started.",
+  "noMatchTitle": "No matching agents",
+  "noMatchDescription": "Try a different search term.",
+  "card": {
+    "unnamedAgent": "Unnamed Agent",
+    "summoning": "Summoning...",
+    "summonFailed": "Failed",
+    "resummon": "Resummon",
+    "delete": "Delete",
+    "predefinedTooltip": "Shared context files (SOUL.md, IDENTITY.md, AGENTS.md) with per-user USER.md instances.",
+    "openTooltip": "Each user gets their own full set of context files.",
+    "evolving": "Evolving",
+    "static": "Static",
+    "evolvingTooltip": "Agent can self-evolve its communication style (SOUL.md). Identity and workflow stay fixed.",
+    "staticTooltip": "Agent style is static. Enable Self-Evolution in settings to allow style adaptation."
+  },
+  "delete": {
+    "title": "Delete Agent",
+    "description": "Permanently delete this agent, all its context files, sessions, and configuration. This action cannot be undone.",
+    "detailDescription": "Are you sure you want to delete \"{{name}}\"? All context files, sessions, and configuration will be permanently removed.",
+    "confirmLabel": "Delete",
+    "defaultCannotDelete": "The default agent cannot be deleted."
+  },
+  "create": {
+    "title": "Create Agent",
+    "displayName": "Display Name *",
+    "displayNamePlaceholder": "My Agent",
+    "agentKey": "Agent Key *",
+    "agentKeyPlaceholder": "e.g. my-agent",
+    "agentKeyHint": "Lowercase, numbers, hyphens",
+    "provider": "Provider *",
+    "selectProvider": "Select provider",
+    "model": "Model *",
+    "enterOrSelectModel": "Enter or select model",
+    "loadingModels": "Loading models...",
+    "check": "Check",
+    "checking": "Checking...",
+    "modelVerified": "Model verified",
+    "verificationFailed": "Verification failed",
+    "noModelsHint": "This provider doesn't list models — type the model ID manually.",
+    "agentType": "Agent Type",
+    "open": "Open",
+    "openSubLabel": "Per-user context",
+    "predefined": "Predefined",
+    "predefinedSubLabel": "Agent-level config",
+    "describeAgent": "Describe Your Agent",
+    "descriptionPlaceholder": "Describe your agent's personality, purpose, and behavior...",
+    "descriptionHint": "AI will automatically generate your agent's context files from this description. Leave empty to start with templates.",
+    "selfEvolution": "Self-Evolution",
+    "selfEvolutionHint": "Allow agent to evolve its style and tone over time via SOUL.md",
+    "cancel": "Cancel",
+    "create": "Create",
+    "creating": "Creating...",
+    "checkAndCreate": "Check & Create",
+    "failedToCreate": "Failed to create agent"
+  },
+  "detail": {
+    "tabs": {
+      "general": "General",
+      "config": "Config",
+      "files": "Files",
+      "shares": "Shares",
+      "links": "Links",
+      "skills": "Skills",
+      "instances": "Instances"
+    },
+    "summonFailed": "Summon Failed",
+    "evolving": "Evolving",
+    "static": "Static",
+    "evolvingTooltipDetail": "Agent can self-evolve its communication style (SOUL.md). Identity and workflow stay fixed.",
+    "staticTooltipDetail": "Agent style is static. Enable Self-Evolution in General tab to allow style adaptation."
+  },
+  "general": {
+    "selfEvolution": "Self-Evolution",
+    "selfEvolutionLabel": "Allow agent to evolve its communication style",
+    "selfEvolutionHint": "When enabled, the agent can update its SOUL.md to refine tone, vocabulary, and response style based on interactions. Identity, name, and operating instructions remain locked.",
+    "selfEvolutionInfo": "Agent will evolve its style over time through SOUL.md updates. Only style and tone are affected — identity and workflow rules stay fixed.",
+    "saveChanges": "Save Changes",
+    "saving": "Saving...",
+    "saved": "Saved",
+    "failedToSave": "Failed to save"
+  },
+  "identity": {
+    "title": "Identity",
+    "agentKey": "Agent Key",
+    "agentKeyHint": "Unique identifier, cannot be changed.",
+    "displayName": "Display Name",
+    "displayNamePlaceholder": "e.g. My Assistant",
+    "displayNameHint": "Friendly name shown in the UI. Leave empty to use the agent key.",
+    "expertiseSummary": "Expertise Summary",
+    "expertiseSummaryPlaceholder": "e.g. Chiêm tinh, bói toán, tử vi, thần số học",
+    "expertiseSummaryHint": "Short description of this agent's expertise. Used for delegation discovery.",
+    "status": "Status",
+    "active": "Active",
+    "inactive": "Inactive",
+    "summonFailed": "Summon Failed",
+    "defaultAgent": "Default Agent"
+  },
+  "llmConfig": {
+    "title": "LLM Configuration",
+    "contextWindow": "Context Window",
+    "contextWindowHint": "Token limit for the model context.",
+    "maxToolIterations": "Max Tool Iterations",
+    "maxToolIterationsHint": "Max tool calls per request."
+  },
+  "workspace": {
+    "title": "Workspace",
+    "workspacePath": "Workspace Path",
+    "workspacePathHint": "Automatically assigned when the agent is created. Per-user subdirectories are created at runtime.",
+    "noWorkspace": "No workspace configured",
+    "restrictToWorkspace": "Restrict to Workspace",
+    "restrictToWorkspaceHint": "Confine file access strictly within the workspace path."
+  },
+  "config": {
+    "saveConfig": "Save Config",
+    "saving": "Saving...",
+    "saved": "Saved",
+    "failedToSave": "Failed to save",
+    "usingGlobalDefaults": "Using global defaults from config.json"
+  },
+  "files": {
+    "readOnly": "Read-only",
+    "readOnlyDesc": "Only the agent owner can edit predefined context files.",
+    "resummon": "Resummon",
+    "editWithAi": "Edit with AI",
+    "resummonTitle": "Resummon Agent",
+    "resummonDesc": "This will regenerate SOUL.md, IDENTITY.md, and optionally USER_PREDEFINED.md from scratch using the original description. Any manual edits to these files will be overwritten.",
+    "cancel": "Cancel",
+    "resummonConfirm": "Resummon",
+    "summoning": "Summoning...",
+    "selectFileToEdit": "Select a file to edit",
+    "selectFileToView": "Select a file to view",
+    "saving": "Saving...",
+    "save": "Save",
+    "loading": "Loading...",
+    "openAgentTitle": "Open Agent - Per-User Context Files",
+    "openAgentDesc1": "This is an open agent. Context files (AGENTS.md, SOUL.md, TOOLS.md, etc.) are personalized for each user. They are automatically created from templates when a user first chats with this agent.",
+    "openAgentDesc2pre": "Agent-level files shown here are empty because open agents store all context per-user in the ",
+    "openAgentDesc2post": " table.",
+    "contextFiles": "Context Files",
+    "contextFile": "Context file",
+    "perUser": "per-user",
+    "emptyFile": "empty",
+    "estTokens": "Est {{tokens}} tokens"
+  },
+  "fileEditor": {
+    "editWithAi": "Edit with AI",
+    "editAiDescription": "Describe what you want to change. AI will read the current files and update them accordingly.",
+    "editAiPlaceholder": "e.g. Make the agent more formal, add Vietnamese language support, change the name to Luna...",
+    "sending": "Sending...",
+    "regenerate": "Regenerate",
+    "cancel": "Cancel"
+  },
+  "shares": {
+    "grantAccess": "Grant Access",
+    "userId": "User ID",
+    "userIdPlaceholder": "Enter user ID...",
+    "role": "Role",
+    "share": "Share",
+    "loadingShares": "Loading shares...",
+    "noShares": "No shares yet",
+    "noSharesDesc": "Share this agent with other users by entering their User ID above.",
+    "user": "User",
+    "revokeTitle": "Revoke Share",
+    "revokeDesc": "Revoke access for user \"{{userId}}\"? They will no longer be able to use this agent.",
+    "revoke": "Revoke"
+  },
+  "links": {
+    "teamsHint": "For multi-agent collaboration with task tracking and quality control, consider using Agent Teams instead. Agent Links are best for simple 1-to-1 delegation between two agents.",
+    "createLink": "Create Link",
+    "targetAgent": "Target Agent",
+    "selectAgent": "Select or search agent...",
+    "direction": "Direction",
+    "description": "Description",
+    "descriptionPlaceholder": "Optional description of the link...",
+    "maxConcurrent": "Max Concurrent",
+    "advancedSettings": "Advanced Settings",
+    "allowedUsers": "Allowed Users",
+    "allowedUsersPlaceholder": "user1, user2, ...",
+    "allowedUsersHint": "If set, only these users can trigger this delegation. Comma-separated.",
+    "deniedUsers": "Denied Users",
+    "deniedUsersPlaceholder": "user3, user4, ...",
+    "deniedUsersHint": "These users are blocked from triggering this delegation. Comma-separated.",
+    "creating": "Creating...",
+    "noLinks": "No agent links yet",
+    "noLinksDesc": "Create links to allow agents to delegate tasks to each other.",
+    "loadingLinks": "Loading links...",
+    "columns": {
+      "target": "Target",
+      "direction": "Direction",
+      "status": "Status",
+      "limit": "Limit"
+    },
+    "deleteTitle": "Delete Link",
+    "deleteDesc": "Remove the delegation link to \"{{name}}\"? Agents will no longer be able to delegate to each other through this link.",
+    "editTitle": "Edit Link",
+    "editDescription": "Update the delegation link settings.",
+    "optionalDescription": "Optional description...",
+    "allowedUsersHintShort": "If set, only these users can trigger this delegation.",
+    "deniedUsersHintShort": "These users are blocked from triggering this delegation."
+  },
+  "skills": {
+    "noSkillsAvailable": "No skills available",
+    "noSkillsDesc": "Upload skills in the Skills page to grant them to agents.",
+    "skillsGranted": "{{granted}} of {{total}} skills granted",
+    "filterSkills": "Filter skills...",
+    "noSkillsMatch": "No skills match your search."
+  },
+  "instances": {
+    "loadingInstances": "Loading instances...",
+    "noInstances": "No user instances yet.",
+    "noInstancesDesc": "Instances are created when users interact with this agent.",
+    "instanceCount": "{{count}} instance",
+    "instanceCount_plural": "{{count}} instances",
+    "selectInstance": "Select an instance to view and edit its USER.md",
+    "loading": "Loading...",
+    "saving": "Saving...",
+    "save": "Save",
+    "saved": "Saved"
+  },
+  "summoning": {
+    "title": "Summoning Your Agent...",
+    "completed": "Summoning Complete!",
+    "failed": "Summoning Failed",
+    "agentReady": "{{name}} is ready!",
+    "weavingSoul": "Weaving the soul of",
+    "wait": "This usually takes few minutes. Please wait...",
+    "continue": "Continue",
+    "retry": "Retry",
+    "retrying": "Retrying...",
+    "done": "done"
+  },
+  "configSections": {
+    "subagents": {
+      "title": "Subagents",
+      "description": "Controls sub-agent spawning limits and behavior",
+      "maxConcurrent": "Max Concurrent",
+      "maxSpawnDepth": "Max Spawn Depth",
+      "maxChildrenPerAgent": "Max Children Per Agent",
+      "archiveAfter": "Archive After (minutes)",
+      "modelOverride": "Model Override",
+      "inheritFromAgent": "(inherit from agent)"
+    },
+    "toolPolicy": {
+      "title": "Tool Policy",
+      "description": "Control which tools this agent can use",
+      "profile": "Profile",
+      "allow": "Allow",
+      "deny": "Deny",
+      "alsoAllow": "Also Allow",
+      "selectToolsAllow": "Select tools to allow...",
+      "selectToolsDeny": "Select tools to deny...",
+      "selectToolsAlsoAllow": "Select additional tools..."
+    },
+    "compaction": {
+      "title": "Compaction",
+      "description": "Context window compaction and memory flush settings",
+      "reserveTokensFloor": "Reserve Tokens Floor",
+      "maxHistoryShare": "Max History Share (0-1)",
+      "minMessages": "Min Messages",
+      "keepLastMessages": "Keep Last Messages",
+      "memoryFlush": "Memory Flush",
+      "softThreshold": "Soft Threshold (tokens)"
+    },
+    "contextPruning": {
+      "title": "Context Pruning",
+      "description": "Trim old tool results to save context window",
+      "mode": "Mode",
+      "keepLastAssistants": "Keep Last Assistants",
+      "softTrimRatio": "Soft Trim Ratio (0-1)",
+      "hardClearRatio": "Hard Clear Ratio (0-1)",
+      "minPrunableToolChars": "Min Prunable Tool Chars",
+      "softTrim": "Soft Trim",
+      "maxChars": "Max Chars",
+      "headChars": "Head Chars",
+      "tailChars": "Tail Chars",
+      "hardClear": "Hard Clear",
+      "enabled": "Enabled",
+      "placeholderText": "Placeholder Text"
+    },
+    "sandbox": {
+      "title": "Sandbox",
+      "description": "Docker sandbox for code execution isolation",
+      "mode": "Mode",
+      "workspaceAccess": "Workspace Access",
+      "image": "Image",
+      "scope": "Scope",
+      "timeout": "Timeout (sec)",
+      "memoryMb": "Memory (MB)",
+      "cpus": "CPUs",
+      "networkEnabled": "Network Enabled"
+    },
+    "memory": {
+      "title": "Memory",
+      "description": "Semantic memory search and embedding configuration",
+      "embeddingProvider": "Embedding Provider",
+      "embeddingModel": "Embedding Model",
+      "maxResults": "Max Results",
+      "maxChunkLen": "Max Chunk Length",
+      "vectorWeight": "Vector Weight",
+      "textWeight": "Text Weight"
+    },
+    "thinking": {
+      "title": "Extended Thinking",
+      "description": "Allow the model to reason before responding. Higher levels use more tokens but produce better results on complex tasks.",
+      "thinkingLevel": "Thinking Level",
+      "off": "Off",
+      "offDesc": "No extended thinking",
+      "low": "Low",
+      "lowDesc": "~4K token budget",
+      "medium": "Medium",
+      "mediumDesc": "~10-16K token budget",
+      "high": "High",
+      "highDesc": "~32K token budget"
+    },
+    "qualityGates": {
+      "title": "Quality Gates",
+      "description": "Validate delegation output before returning to the caller",
+      "noGates": "No quality gates configured. Click \"Add Gate\" to create one.",
+      "addGate": "Add Gate",
+      "gateNumber": "Gate #{{number}}",
+      "type": "Type",
+      "reviewerAgentKey": "Reviewer Agent Key",
+      "command": "Command",
+      "blockOnFailure": "Block on Failure",
+      "maxRetries": "Max Retries",
+      "timeout": "Timeout (seconds)"
+    },
+    "otherConfig": {
+      "title": "Other Config",
+      "description": "Additional JSON config for advanced settings not covered by other sections",
+      "formatJson": "Format JSON",
+      "invalidJson": "Invalid JSON syntax"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/approvals.json b/ui/web/src/i18n/locales/en/approvals.json
new file mode 100644
index 00000000..a090932b
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/approvals.json
@@ -0,0 +1,23 @@
+{
+  "title": "Approvals",
+  "description": "Pending execution approvals",
+  "pending": "{{count}} pending",
+  "emptyTitle": "No pending approvals",
+  "emptyDescription": "All execution requests have been resolved. New requests will appear here in real-time.",
+  "allowOnce": "Allow Once",
+  "allowAlways": "Allow Always",
+  "deny": "Deny",
+  "confirmAllowOnce": {
+    "title": "Allow Once",
+    "description": "Allow execution of \"{{command}}\" from agent \"{{agentId}}\"?"
+  },
+  "confirmAllowAlways": {
+    "title": "Allow Always",
+    "description": "Permanently allow \"{{command}}\" for agent \"{{agentId}}\"? This command will be auto-approved in the future."
+  },
+  "confirmDeny": {
+    "title": "Deny Execution",
+    "description": "Deny execution request \"{{command}}\" from agent \"{{agentId}}\"?",
+    "confirmLabel": "Deny"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/channels.json b/ui/web/src/i18n/locales/en/channels.json
new file mode 100644
index 00000000..ff1322d7
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/channels.json
@@ -0,0 +1,213 @@
+{
+  "title": "Channels",
+  "description": "Manage channel instances",
+  "statusDescription": "Communication channel status",
+  "addChannel": "Add Channel",
+  "refresh": "Refresh",
+  "searchPlaceholder": "Search channels...",
+  "emptyTitle": "No channels",
+  "emptyDescription": "Add your first channel instance to get started.",
+  "emptyStatusDescription": "No communication channels are configured.",
+  "noMatchTitle": "No matching channels",
+  "noMatchDescription": "Try a different search term.",
+  "columns": {
+    "name": "Name",
+    "type": "Type",
+    "agent": "Agent",
+    "status": "Status",
+    "enabled": "Enabled",
+    "actions": "Actions"
+  },
+  "status": {
+    "running": "Running",
+    "stopped": "Stopped"
+  },
+  "enabled": "Enabled",
+  "disabled": "Disabled",
+  "actions": {
+    "reauthenticate": "Re-authenticate",
+    "authenticate": "Authenticate to start channel"
+  },
+  "delete": {
+    "title": "Delete Channel Instance",
+    "description": "Are you sure you want to delete \"{{name}}\"? This action cannot be undone.",
+    "confirmLabel": "Delete"
+  },
+  "form": {
+    "createTitle": "Create Channel Instance",
+    "editTitle": "Edit Channel Instance",
+    "key": "Key *",
+    "keyPlaceholder": "my-telegram-bot",
+    "keyHint": "Unique slug used as channel identifier",
+    "displayName": "Display Name",
+    "displayNamePlaceholder": "Sales Bot",
+    "channelType": "Channel Type *",
+    "agent": "Agent *",
+    "selectAgent": "Select agent",
+    "credentials": "Credentials",
+    "credentialsHint": "(leave blank to keep current)",
+    "credentialsEncrypted": "Encrypted server-side. Never returned in API responses.",
+    "configuration": "Configuration",
+    "enabled": "Enabled",
+    "cancel": "Cancel",
+    "create": "Create",
+    "update": "Update",
+    "saving": "Saving...",
+    "step": "Step {{current}} of {{total}}",
+    "authenticate": "Authenticate — {{label}}",
+    "configure": "Configure — {{label}}",
+    "skip": "Skip",
+    "done": "Done",
+    "errors": {
+      "keyRequired": "Key is required",
+      "keySlug": "Key must be a valid slug (lowercase letters, numbers, hyphens only)",
+      "agentRequired": "Agent is required",
+      "requiredFields": "Required: {{fields}}",
+      "failedSave": "Failed to save",
+      "failedSaveConfig": "Failed to save configuration"
+    },
+    "authStatus": {
+      "authenticated": "Authenticated",
+      "notAuthenticated": "Not authenticated",
+      "useQrHint": "— Use the QR login button from the channels table"
+    }
+  },
+  "detail": {
+    "agent": "Agent: {{name}}",
+    "tabs": {
+      "general": "General",
+      "config": "Config",
+      "credentials": "Credentials",
+      "groups": "Groups",
+      "writers": "Writers"
+    },
+    "general": {
+      "name": "Name",
+      "nameHint": "Unique slug (read-only)",
+      "channelType": "Channel Type",
+      "displayName": "Display Name",
+      "displayNamePlaceholder": "Friendly name",
+      "agent": "Agent",
+      "selectAgent": "Select agent",
+      "enabled": "Enabled",
+      "saved": "Saved",
+      "saveChanges": "Save Changes",
+      "saving": "Saving..."
+    },
+    "credentials": {
+      "hint": "Leave fields blank to keep current values. Credentials are encrypted server-side and never returned in API responses.",
+      "noSchema": "No credentials schema for this channel type.",
+      "noCredentials": "No credentials to update",
+      "failedSave": "Failed to save",
+      "saved": "Saved",
+      "updateCredentials": "Update Credentials",
+      "saving": "Saving..."
+    },
+    "config": {
+      "noSchema": "No configuration schema for this channel type.",
+      "saved": "Saved",
+      "saveConfig": "Save Config",
+      "saving": "Saving..."
+    },
+    "groups": {
+      "saved": "Saved",
+      "saveGroups": "Save Groups",
+      "saving": "Saving..."
+    },
+    "writers": {
+      "description": "Manage which users are allowed to write/edit files in group chats.",
+      "groups": "Groups",
+      "noWriterGroups": "No writer groups",
+      "noWriterGroupsHint": "Use the form below to add writers to a group.",
+      "loadingWriters": "Loading writers...",
+      "noWriters": "No writers in this group.",
+      "writersCount": "{{count}} writer",
+      "writersCountPlural": "{{count}} writers",
+      "columns": {
+        "userId": "User ID",
+        "name": "Name",
+        "username": "Username"
+      },
+      "addForm": {
+        "title": "Add Writer to New Group",
+        "hint": "Add a writer to a group that doesn't appear in the list above.",
+        "groupId": "Group ID *",
+        "groupIdPlaceholder": "e.g. group:telegram:-100123456",
+        "userId": "User ID *",
+        "userIdPlaceholder": "e.g. 12345678",
+        "displayName": "Display Name",
+        "username": "Username",
+        "optional": "Optional",
+        "usernameWithout": "Optional (without @)",
+        "adding": "Adding...",
+        "addWriter": "Add Writer",
+        "add": "Add",
+        "errors": {
+          "groupUserRequired": "Group ID and User ID are required",
+          "failedAdd": "Failed to add writer"
+        }
+      }
+    }
+  },
+  "groupOverrides": {
+    "title": "Group & Topic Overrides",
+    "hint": "Override channel defaults per group chat or forum topic. Use \"*\" as group ID for wildcard defaults.",
+    "groupLabel": "Group: {{id}}",
+    "groupWildcard": "* (wildcard)",
+    "addGroupPlaceholder": "Chat ID (e.g. -100123456) or *",
+    "addGroup": "Add Group",
+    "topicOverrides": "Topic Overrides",
+    "topicLabel": "Topic: {{id}}",
+    "addTopicPlaceholder": "Topic thread ID",
+    "addTopic": "Add Topic",
+    "fields": {
+      "groupPolicy": "Group Policy",
+      "requireMention": "Require @mention",
+      "enabled": "Enabled",
+      "allowedUsers": "Allowed Users",
+      "allowedUsersPlaceholder": "One user ID per line",
+      "skillsFilter": "Skills Filter",
+      "skillsPlaceholder": "One skill name per line (empty = inherit)",
+      "toolAllow": "Tool Allow",
+      "toolAllowPlaceholder": "Select allowed tools (empty = inherit all)...",
+      "toolAllowHint": "Restrict which tools are available in this group. Supports group names like \"group:web\", \"group:fs\". Empty = inherit all tools.",
+      "systemPrompt": "System Prompt",
+      "systemPromptPlaceholder": "Additional system prompt for this group/topic",
+      "inherit": "Inherit (channel default)",
+      "yes": "Yes",
+      "no": "No"
+    }
+  },
+  "toast": {
+    "created": "Channel created",
+    "createdDesc": "{{name}} has been added",
+    "updated": "Channel updated",
+    "deleted": "Channel deleted",
+    "failedCreate": "Failed to create channel",
+    "failedUpdate": "Failed to update channel",
+    "failedDelete": "Failed to delete channel"
+  },
+  "zalo": {
+    "allowedUsers": "Allowed Users",
+    "loadContacts": "Load Contacts",
+    "loading": "Loading...",
+    "searchContacts": "Search contacts...",
+    "friends": "Friends",
+    "groups": "Groups",
+    "membersCount": "{{count}} members",
+    "noContacts": "No contacts found",
+    "noContactsMatch": "No contacts match \"{{search}}\"",
+    "addManualPlaceholder": "Add ID manually",
+    "add": "Add",
+    "zaloIdsHint": "Zalo user IDs or group IDs",
+    "completeQrLogin": "Complete QR login to load contacts",
+    "loginQr": "Login with QR — {{name}}",
+    "loginSuccessful": "Login successful! Channel starting...",
+    "generatingQr": "Generating QR code...",
+    "scanHint": "Scan with your Zalo app (expires in ~100s)",
+    "loginSuccessLoading": "Login successful! Loading contacts...",
+    "retry": "Retry",
+    "close": "Close",
+    "skip": "Skip"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/chat.json b/ui/web/src/i18n/locales/en/chat.json
new file mode 100644
index 00000000..3d512ee0
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/chat.json
@@ -0,0 +1,20 @@
+{
+  "newChat": "New Chat",
+  "openSessions": "Open sessions",
+  "readOnly": "Read-only — this session belongs to another user",
+  "empty": {
+    "title": "Start a conversation",
+    "description": "Send a message to begin chatting with the agent."
+  },
+  "media": {
+    "image": "Image",
+    "video": "Video",
+    "audio": "Audio",
+    "voice": "Voice message",
+    "document": "Document",
+    "animation": "Animation",
+    "attached": "attached"
+  },
+  "forwardedFrom": "Forwarded from",
+  "replyingTo": "Replying to"
+}
diff --git a/ui/web/src/i18n/locales/en/common.json b/ui/web/src/i18n/locales/en/common.json
new file mode 100644
index 00000000..292f4a15
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/common.json
@@ -0,0 +1,104 @@
+{
+  "refresh": "Refresh",
+  "cancel": "Cancel",
+  "confirm": "Confirm",
+  "delete": "Delete",
+  "save": "Save",
+  "edit": "Edit",
+  "create": "Create",
+  "add": "Add",
+  "view": "View",
+  "filter": "Filter",
+  "search": "Search",
+  "retry": "Retry",
+  "manage": "Manage",
+  "upload": "Upload",
+  "close": "Close",
+  "back": "Back",
+  "update": "Update",
+  "enabled": "Enabled",
+  "disabled": "Disabled",
+  "yes": "Yes",
+  "no": "No",
+  "loading": "Loading...",
+  "saving": "Saving...",
+  "creating": "Creating...",
+  "connecting": "Connecting...",
+  "connected": "Connected",
+  "disconnected": "Disconnected",
+  "running": "Running",
+  "stopped": "Stopped",
+  "pending": "Pending",
+  "completed": "Completed",
+  "failed": "Failed",
+  "cancelled": "Cancelled",
+  "unknown": "Unknown",
+  "active": "active",
+  "items": "items",
+  "rows": "Rows",
+  "pageOf": "Page {{page}} of {{totalPages}}",
+  "messages": "messages",
+  "cached": "cached",
+  "live": "Live",
+  "noDescription": "No description",
+  "unsavedChanges": "Unsaved changes",
+  "tryDifferentSearch": "Try a different search term.",
+  "notSet": "Not set",
+  "default": "default",
+  "optional": "optional",
+  "required": "required",
+  "actions": "Actions",
+  "status": "Status",
+  "name": "Name",
+  "description": "Description",
+  "type": "Type",
+  "none": "none",
+  "all": "All",
+  "global": "Global",
+  "agent": "Agent",
+  "saved": "Saved",
+  "saveChanges": "Save Changes",
+  "saveConfig": "Save Config",
+  "checkAndCreate": "Check & Create",
+  "checking": "Checking...",
+  "format": "Format JSON",
+  "invalidJson": "Invalid JSON syntax",
+  "usingGlobalDefaults": "Using global defaults from config.json",
+  "disconnectedGateway": "Disconnected from gateway. Attempting to reconnect...",
+  "noFiles": "No files found.",
+  "selectFileToView": "Select a file to view its content",
+  "typeToConfirmPrefix": "Type",
+  "typeToConfirmSuffix": "to confirm.",
+  "searchPlaceholder": "Search...",
+  "noSessions": "No sessions yet. Start a chat!",
+  "noAgentsAvailable": "No agents available",
+  "selectAgent": "Select agent",
+  "sendMessage": "Send a message... (Shift+Enter for new line)",
+  "stopGeneration": "Stop generation",
+  "sendMessageTitle": "Send message",
+  "thinking": "Thinking",
+  "thinkingStreaming": "Thinking...",
+  "toolArguments": "Arguments",
+  "toolResult": "Result",
+  "skillActivating": "Activating...",
+  "skillActivated": "Activated",
+  "toolRunning": "Running...",
+  "toolDone": "Done",
+  "toolFailed": "Failed",
+  "filesBack": "Files",
+  "noProvidersConfigured": "No providers configured",
+  "loadingModels": "Loading models...",
+  "modelVerified": "Model verified",
+  "verificationFailed": "Verification failed",
+  "provider": "Provider",
+  "model": "Model",
+  "selectProvider": "Select provider",
+  "enterOrSelectModel": "Enter or select model",
+  "providerTip": "LLM provider name. Must match a configured provider.",
+  "modelTip": "Model ID to use.",
+  "check": "Check",
+  "builtinTools": "Built-in",
+  "customTools": "Custom",
+  "selectOrTypeTools": "Select or type tool names...",
+  "typeAndPressEnter": "Type and press Enter..."
+}
diff --git a/ui/web/src/i18n/locales/en/cron.json b/ui/web/src/i18n/locales/en/cron.json
new file mode 100644
index 00000000..e745d40d
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/cron.json
@@ -0,0 +1,102 @@
+{
+  "title": "Cron",
+  "description": "Schedule recurring agent tasks",
+  "newJob": "New Job",
+  "emptyTitle": "No cron jobs",
+  "emptyDescription": "Create a cron job to schedule recurring agent tasks.",
+  "columns": {
+    "enabled": "Enabled",
+    "name": "Name",
+    "schedule": "Schedule",
+    "message": "Message",
+    "agent": "Agent",
+    "actions": "Actions"
+  },
+  "runNow": "Run now",
+  "running": "Running...",
+  "runHistory": "Run history",
+  "defaultAgent": "default",
+  "create": {
+    "title": "Create Cron Job",
+    "name": "Name",
+    "namePlaceholder": "my-daily-task",
+    "nameHint": "Lowercase letters, numbers, and hyphens only",
+    "agentId": "Agent ID (optional)",
+    "agentIdPlaceholder": "default",
+    "scheduleType": "Schedule Type",
+    "every": "Every",
+    "cron": "Cron",
+    "once": "Once",
+    "intervalSeconds": "Interval (seconds)",
+    "cronExpression": "Cron Expression",
+    "cronHint": "Standard 5-field cron: min hour day month weekday",
+    "onceDesc": "The job will run once, approximately 1 minute from now.",
+    "message": "Message",
+    "messagePlaceholder": "What should the agent do?",
+    "cancel": "Cancel",
+    "create": "Create",
+    "creating": "Creating..."
+  },
+  "enable": {
+    "title": "Enable Cron Job",
+    "description": "Enable \"{{name}}\"? It will start running on schedule.",
+    "confirmLabel": "Enable"
+  },
+  "disable": {
+    "title": "Disable Cron Job",
+    "description": "Disable \"{{name}}\"? It will stop running until re-enabled.",
+    "confirmLabel": "Disable"
+  },
+  "delete": {
+    "title": "Delete Cron Job",
+    "description": "Delete \"{{name}}\"? This cannot be undone.",
+    "confirmLabel": "Delete"
+  },
+  "runLog": {
+    "title": "Run Log: {{name}}",
+    "noHistory": "No run history yet.",
+    "loading": "Loading..."
+  },
+  "detail": {
+    "runNow": "Run Now",
+    "running": "Running...",
+    "disable": "Disable",
+    "enable": "Enable",
+    "delete": "Delete",
+    "enabled": "enabled",
+    "disabled": "disabled",
+    "runningStatus": "running...",
+    "payload": "Payload",
+    "empty": "(empty)",
+    "deliverDirect": "Deliver: direct",
+    "channel": "Channel: {{name}}",
+    "to": "To: {{name}}",
+    "lastError": "Last Error",
+    "runHistory": "Run History",
+    "refresh": "Refresh",
+    "noHistory": "No run history yet.",
+    "inOut": "{{input}} in / {{output}} out",
+    "infoRows": {
+      "schedule": "Schedule",
+      "timezone": "Timezone",
+      "nextRun": "Next Run",
+      "lastRun": "Last Run",
+      "created": "Created",
+      "updated": "Updated",
+      "autoDelete": "Auto-delete",
+      "autoDeleteValue": "Yes (one-time)"
+    }
+  },
+  "toast": {
+    "created": "Cron job created",
+    "createdDesc": "{{name}} has been added",
+    "enabled": "Cron job enabled",
+    "disabled": "Cron job disabled",
+    "deleted": "Cron job deleted",
+    "triggered": "Cron job triggered",
+    "failedCreate": "Failed to create cron job",
+    "failedToggle": "Failed to toggle cron job",
+    "failedDelete": "Failed to delete cron job",
+    "failedRun": "Failed to run cron job"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/delegations.json b/ui/web/src/i18n/locales/en/delegations.json
new file mode 100644
index 00000000..d3d6151d
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/delegations.json
@@ -0,0 +1,41 @@
+{
+  "title": "Delegations",
+  "description": "Agent delegation history and results",
+  "sourceFilterPlaceholder": "Source agent...",
+  "targetFilterPlaceholder": "Target agent...",
+  "filter": "Filter",
+  "emptyTitle": "No delegations",
+  "emptyDescription": "No delegation records found. Delegations are recorded when agents delegate tasks to other agents.",
+  "columns": {
+    "sourceTarget": "Source / Target",
+    "task": "Task",
+    "status": "Status",
+    "mode": "Mode",
+    "duration": "Duration",
+    "time": "Time"
+  },
+  "statusFilter": {
+    "all": "All",
+    "pending": "Pending",
+    "running": "Running",
+    "completed": "Completed",
+    "failed": "Failed",
+    "cancelled": "Cancelled"
+  },
+  "detail": {
+    "title": "Delegation Detail",
+    "notFound": "Delegation not found.",
+    "source": "Source:",
+    "target": "Target:",
+    "status": "Status:",
+    "mode": "Mode:",
+    "duration": "Duration:",
+    "iterations": "Iterations:",
+    "created": "Created:",
+    "completed": "Completed:",
+    "trace": "Trace:",
+    "task": "Task",
+    "result": "Result",
+    "error": "Error"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/events.json b/ui/web/src/i18n/locales/en/events.json
new file mode 100644
index 00000000..0afcaf11
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/events.json
@@ -0,0 +1,34 @@
+{
+  "title": "Realtime Events",
+  "description": "Live WebSocket events across all teams and agents",
+  "live": "Live",
+  "paused": "Paused",
+  "resume": "Resume",
+  "pause": "Pause",
+  "clear": "Clear",
+  "scrollToBottom": "Scroll to bottom",
+  "eventCount": "{{count}} event",
+  "eventCountPlural": "{{count}} events",
+  "categories": {
+    "all": "All",
+    "delegation": "Delegation",
+    "task": "Task",
+    "message": "Message",
+    "agent": "Agent",
+    "teamCrud": "Team CRUD",
+    "agentLink": "Agent Link"
+  },
+  "filters": {
+    "allTeams": "All teams",
+    "allUsers": "All users",
+    "allChats": "All chats"
+  },
+  "global": "Global",
+  "emptyTitle": "No events yet",
+  "emptyPaused": "Event capture is paused. Resume to see new events.",
+  "emptyWaiting": "Waiting for real-time events... Events will appear as agents work.",
+  "detail": {
+    "copy": "Copy",
+    "copied": "Copied"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/login.json b/ui/web/src/i18n/locales/en/login.json
new file mode 100644
index 00000000..084cb299
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/login.json
@@ -0,0 +1,32 @@
+{
+  "subtitle": "Sign in to the gateway dashboard",
+  "tabs": {
+    "token": "Token",
+    "pairing": "Pairing"
+  },
+  "token": {
+    "userId": "User ID",
+    "userIdPlaceholder": "your-user-id",
+    "gatewayToken": "Gateway Token",
+    "tokenPlaceholder": "Bearer token",
+    "connect": "Connect",
+    "connecting": "Connecting...",
+    "errorInvalidCredentials": "Invalid credentials. Check your token and user ID.",
+    "errorServer": "Server returned {{status}}. Please try again.",
+    "errorCannotConnect": "Cannot connect to gateway. Check if the server is running."
+  },
+  "pairing": {
+    "userId": "User ID",
+    "userIdPlaceholder": "your-user-id",
+    "noTokenNeeded": "No token needed. A pairing code will be generated for an admin to approve.",
+    "requestAccess": "Request Access",
+    "connecting": "Connecting...",
+    "errorConnectionLost": "Connection lost. Please try again.",
+    "errorCannotConnect": "Could not connect to gateway.",
+    "askAdmin": "Ask an admin to approve this code:",
+    "orRun": "Or run:",
+    "waitingForApproval": "Waiting for approval...",
+    "cancel": "Cancel",
+    "approved": "Access approved! Redirecting..."
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/logs.json b/ui/web/src/i18n/locales/en/logs.json
new file mode 100644
index 00000000..a2065416
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/logs.json
@@ -0,0 +1,15 @@
+{
+  "title": "Logs",
+  "description": "Live log tailing",
+  "descriptionLive": "Live tailing at {{level}} level",
+  "live": "Live",
+  "start": "Start",
+  "stop": "Stop",
+  "clear": "Clear",
+  "filterPlaceholder": "Filter logs...",
+  "logLevelTitle": "Log level",
+  "emptyWaiting": "Waiting for logs...",
+  "emptyFilter": "No logs match filter.",
+  "emptyStart": "Click \"Start\" to begin streaming logs.",
+  "count": "{{filtered}}/{{total}}"
+}
diff --git a/ui/web/src/i18n/locales/en/mcp.json b/ui/web/src/i18n/locales/en/mcp.json
new file mode 100644
index 00000000..aa483b78
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/mcp.json
@@ -0,0 +1,99 @@
+{
+  "title": "MCP Servers",
+  "description": "Manage Model Context Protocol server connections",
+  "addServer": "Add Server",
+  "searchPlaceholder": "Search servers...",
+  "emptyTitle": "No MCP servers",
+  "emptyDescription": "Add your first MCP server to get started.",
+  "noMatchTitle": "No matching servers",
+  "noMatchDescription": "Try a different search term.",
+  "columns": {
+    "name": "Name",
+    "transport": "Transport",
+    "tools": "Tools",
+    "enabled": "Enabled",
+    "createdBy": "Created By",
+    "actions": "Actions"
+  },
+  "viewTools": "View tools",
+  "manageGrants": "Manage grants",
+  "delete": {
+    "title": "Delete MCP Server",
+    "description": "Are you sure you want to delete \"{{name}}\"? This will also remove all associated grants.",
+    "confirmLabel": "Delete"
+  },
+  "form": {
+    "createTitle": "Add MCP Server",
+    "editTitle": "Edit MCP Server",
+    "name": "Name *",
+    "nameHint": "Lowercase letters, numbers, and hyphens only",
+    "displayName": "Display Name",
+    "transport": "Transport *",
+    "command": "Command *",
+    "args": "Args (comma-separated)",
+    "argsPlaceholder": "--flag1, --flag2",
+    "url": "URL *",
+    "headers": "Headers",
+    "headerKeyPlaceholder": "Header name",
+    "headerValuePlaceholder": "Header value",
+    "addHeader": "Add Header",
+    "env": "Environment Variables",
+    "envKeyPlaceholder": "Variable name",
+    "envValuePlaceholder": "Value",
+    "addVariable": "Add Variable",
+    "toolPrefix": "Tool Prefix",
+    "toolPrefixHint": "Auto-derived from name if empty.",
+    "timeout": "Timeout (seconds)",
+    "enabled": "Enabled",
+    "testConnection": "Test Connection",
+    "testing": "Testing...",
+    "toolsFound": "{{count}} tools found",
+    "cancel": "Cancel",
+    "create": "Create",
+    "update": "Update",
+    "saving": "Saving...",
+    "errors": {
+      "nameRequired": "Name and transport are required",
+      "nameSlug": "Name must be a valid slug (lowercase letters, numbers, hyphens only)",
+      "commandRequired": "Command is required for stdio transport",
+      "urlRequired": "URL is required for SSE/HTTP transport",
+      "connectionFailed": "Connection failed"
+    }
+  },
+  "grants": {
+    "title": "Agent Grants - {{name}}",
+    "currentGrants": "Current Grants",
+    "allToolsAllowed": "All tools allowed",
+    "addGrant": "Add Agent Grant",
+    "editGrant": "Edit Grant",
+    "selectAgent": "Select agent...",
+    "toolAllowList": "Tool allow list (optional)",
+    "toolDenyList": "Tool deny list (optional)",
+    "allowPlaceholder": "Select tools to allow...",
+    "denyPlaceholder": "Select tools to deny...",
+    "grant": "Grant",
+    "update": "Update",
+    "cancel": "Cancel",
+    "agentRequired": "Agent is required",
+    "failedGrant": "Failed to grant",
+    "failedRevoke": "Failed to revoke"
+  },
+  "tools": {
+    "title": "Tools — {{name}}",
+    "prefix": "prefix:",
+    "discovering": "Discovering tools...",
+    "noToolsTitle": "No tools discovered",
+    "noToolsDescription": "The server may be offline or has no tools registered.",
+    "failedLoad": "Failed to load tools",
+    "filterPlaceholder": "Filter tools...",
+    "noMatch": "No matching tools"
+  },
+  "toast": {
+    "created": "MCP server created",
+    "updated": "MCP server updated",
+    "deleted": "MCP server deleted",
+    "failedCreate": "Failed to create MCP server",
+    "failedUpdate": "Failed to update MCP server",
+    "failedDelete": "Failed to delete MCP server"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/memory.json b/ui/web/src/i18n/locales/en/memory.json
new file mode 100644
index 00000000..4643a373
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/memory.json
@@ -0,0 +1,166 @@
+{
+  "title": "Memory",
+  "description": "Browse and manage agent memory documents, chunks, and embeddings",
+  "search": "Search",
+  "create": "Create",
+  "indexAll": "Index All",
+  "indexing": "Indexing...",
+  "emptyTitle": "No memory documents",
+  "emptyAgentDescription": "This agent has no memory documents yet.",
+  "emptyGlobalDescription": "No memory documents found across any agent.",
+  "filters": {
+    "agent": "Agent",
+    "allAgents": "All agents",
+    "scope": "Scope",
+    "allScope": "All (global + personal)"
+  },
+  "tabs": {
+    "documents": "Documents",
+    "knowledgeGraph": "Knowledge Graph"
+  },
+  "columns": {
+    "path": "Path",
+    "agent": "Agent",
+    "scope": "Scope",
+    "hash": "Hash",
+    "updated": "Updated",
+    "actions": "Actions"
+  },
+  "scopeLabel": {
+    "personal": "Personal",
+    "global": "Global"
+  },
+  "delete": {
+    "title": "Delete Memory Document",
+    "description": "Are you sure you want to delete \"{{path}}\"? This will also delete all associated chunks and embeddings.",
+    "confirmLabel": "Delete"
+  },
+  "createDialog": {
+    "title": "Create Memory Document",
+    "path": "Path *",
+    "pathPlaceholder": "e.g. notes/project-overview.md",
+    "content": "Content *",
+    "contentPlaceholder": "Document content...",
+    "agentId": "Agent *",
+    "agentIdPlaceholder": "Select agent...",
+    "scope": "Scope",
+    "existingScope": "Existing scope",
+    "customScope": "Custom",
+    "selectGroupUser": "Select group/user...",
+    "scopeHint": "Global = shared across all users. Personal = scoped to a specific user or group chat.",
+    "autoIndex": "Auto-index after creation",
+    "agentRequired": "Please select an agent",
+    "pathRequired": "Path is required",
+    "contentRequired": "Content is required",
+    "cancel": "Cancel",
+    "create": "Create",
+    "creating": "Creating..."
+  },
+  "documentDialog": {
+    "title": "Memory Document",
+    "path": "Path:",
+    "agent": "Agent:",
+    "scope": "Scope:",
+    "hash": "Hash:",
+    "updated": "Updated:",
+    "content": "Content",
+    "chunks": "Chunks ({{count}})",
+    "chunkIndex": "Chunk {{index}}",
+    "noChunks": "No chunks",
+    "embedded": "Embedded",
+    "noEmbedding": "No embedding"
+  },
+  "searchDialog": {
+    "title": "Search Memory",
+    "query": "Search Query",
+    "queryPlaceholder": "Enter search query...",
+    "agentId": "Agent ID",
+    "agentIdPlaceholder": "Filter by agent...",
+    "limit": "Limit",
+    "search": "Search",
+    "searching": "Searching...",
+    "results": "Results",
+    "noResults": "No results found",
+    "similarity": "similarity",
+    "path": "Path:"
+  },
+  "kg": {
+    "emptyTitle": "No entities",
+    "emptyDescription": "No knowledge graph entities for this agent yet.",
+    "emptySearchDescription": "No entities match your search.",
+    "stats": {
+      "entities": "Entities: {{count}}",
+      "relations": "Relations: {{count}}"
+    },
+    "search": {
+      "placeholder": "Search entities...",
+      "button": "Search",
+      "clear": "Clear"
+    },
+    "refresh": "Refresh",
+    "extract": "Extract",
+    "columns": {
+      "name": "Name",
+      "type": "Type",
+      "description": "Description",
+      "confidence": "Confidence",
+      "actions": "Actions",
+      "observations": "Observations",
+      "relations": "Relations"
+    },
+    "deleteEntity": {
+      "title": "Delete Entity",
+      "description": "Delete \"{{name}}\"? This will also delete all associated relations.",
+      "confirmLabel": "Delete"
+    },
+    "entity": {
+      "externalId": "External ID:",
+      "confidence": "Confidence:",
+      "description": "Description:",
+      "source": "Source:",
+      "properties": "Properties:",
+      "relations": "Relations",
+      "traverse": "Traverse (2-hop)",
+      "traversing": "Traversing...",
+      "loading": "Loading...",
+      "noRelations": "No relations found.",
+      "traversalResults": "Traversal Results ({{count}})",
+      "direction": {
+        "outgoing": "→ outgoing",
+        "incoming": "← incoming"
+      },
+      "columns": {
+        "direction": "Direction",
+        "relation": "Relation",
+        "target": "Target",
+        "confidence": "Confidence"
+      }
+    },
+    "extractDialog": {
+      "title": "Extract Entities from Text",
+      "providerLabel": "Extraction Provider",
+      "modelLabel": "Extraction Model",
+      "textLabel": "Text to extract from",
+      "textPlaceholder": "Paste conversation text, notes, or any content to extract entities and relations from...",
+      "extract": "Extract",
+      "extracting": "Extracting...",
+      "cancel": "Cancel",
+      "agentId": "Agent ID",
+      "agentIdPlaceholder": "Leave blank for global"
+    },
+    "graphView": {
+      "loading": "Loading graph...",
+      "empty": "No entities to visualize",
+      "nodes": "{{count}} nodes",
+      "edges": "{{count}} edges"
+    }
+  },
+  "toast": {
+    "created": "Memory document created",
+    "deleted": "Memory document deleted",
+    "indexed": "All documents indexed",
+    "failedCreate": "Failed to create document",
+    "failedDelete": "Failed to delete document",
+    "failedIndex": "Failed to index documents"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/nodes.json b/ui/web/src/i18n/locales/en/nodes.json
new file mode 100644
index 00000000..ce95fb29
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/nodes.json
@@ -0,0 +1,35 @@
+{
+  "title": "Nodes",
+  "description": "Manage paired devices and pending pairing requests",
+  "emptyTitle": "No devices",
+  "emptyDescription": "No paired devices or pending pairing requests.",
+  "pendingRequests": "Pending Requests ({{count}})",
+  "pairedDevices": "Paired Devices ({{count}})",
+  "sender": "Sender:",
+  "chat": "Chat:",
+  "columns": {
+    "channel": "Channel",
+    "senderId": "Sender ID",
+    "paired": "Paired",
+    "by": "By",
+    "actions": "Actions"
+  },
+  "approve": "Approve",
+  "deny": "Deny",
+  "revoke": "Revoke",
+  "confirmApprove": {
+    "title": "Approve Pairing",
+    "description": "Approve pairing request from {{channel}}:{{senderId}} (code: {{code}})? This device will be able to interact with agents.",
+    "confirmLabel": "Approve"
+  },
+  "confirmDeny": {
+    "title": "Deny Pairing",
+    "description": "Deny pairing request from {{channel}}:{{senderId}} (code: {{code}})? The request will be removed.",
+    "confirmLabel": "Deny"
+  },
+  "confirmRevoke": {
+    "title": "Revoke Device",
+    "description": "Revoke pairing for {{channel}}:{{senderId}}? The device will need to re-pair.",
+    "confirmLabel": "Revoke"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/overview.json b/ui/web/src/i18n/locales/en/overview.json
new file mode 100644
index 00000000..4501b027
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/overview.json
@@ -0,0 +1,74 @@
+{
+  "title": "Dashboard",
+  "description": "Gateway overview and quota usage",
+  "statCards": {
+    "requestsToday": "Requests Today",
+    "tokensToday": "Tokens Today",
+    "agents": "Agents",
+    "channels": "Channels",
+    "running": "running",
+    "online": "online",
+    "users": "{{count}} users",
+    "inOut": "{{input}} in / {{output}} out"
+  },
+  "providers": {
+    "noProvidersTitle": "No LLM providers configured",
+    "noEnabledTitle": "No LLM providers enabled",
+    "noProvidersDesc": "You need to add at least one LLM provider before agents can work. ",
+    "noEnabledDesc": "All providers are currently disabled. Enable at least one to start using agents. ",
+    "goToSettings": "Go to Provider Settings"
+  },
+  "systemHealth": {
+    "title": "System Health",
+    "uptime": "Uptime",
+    "database": "Database",
+    "providers": "Providers",
+    "tools": "Tools",
+    "sessions": "Sessions",
+    "clients": "Clients",
+    "channels": "Channels",
+    "active": "{{count}} active",
+    "none": "none"
+  },
+  "connectedClients": {
+    "title": "Connected Clients",
+    "noClients": "No clients connected",
+    "columns": {
+      "ip": "IP",
+      "user": "User",
+      "role": "Role",
+      "connected": "Connected"
+    },
+    "you": "you"
+  },
+  "cronJobs": {
+    "title": "Cron Jobs",
+    "manage": "Manage",
+    "noJobs": "No cron jobs configured",
+    "disabled": "disabled"
+  },
+  "recentRequests": {
+    "title": "Recent Requests",
+    "viewAll": "View All",
+    "noRequests": "No recent requests",
+    "columns": {
+      "time": "Time",
+      "name": "Name",
+      "user": "User",
+      "channel": "Channel",
+      "tokens": "Tokens",
+      "duration": "Duration",
+      "status": "Status"
+    }
+  },
+  "quotaUsage": {
+    "title": "Quota Usage",
+    "columns": {
+      "userGroup": "User / Group",
+      "hour": "Hour",
+      "day": "Day",
+      "week": "Week"
+    },
+    "noLimit": "no limit"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/pending-messages.json b/ui/web/src/i18n/locales/en/pending-messages.json
new file mode 100644
index 00000000..4eadfece
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/pending-messages.json
@@ -0,0 +1,31 @@
+{
+  "title": "Pending Messages",
+  "description": "Buffered channel messages awaiting agent processing",
+  "emptyTitle": "No pending messages",
+  "emptyDescription": "No buffered message groups found. Messages appear here when channels buffer incoming messages before agent processing.",
+  "columns": {
+    "channel": "Channel",
+    "group": "Group",
+    "messages": "Messages",
+    "status": "Status",
+    "lastActivity": "Last Activity",
+    "actions": "Actions"
+  },
+  "status": {
+    "compacted": "Compacted",
+    "raw": "Raw"
+  },
+  "compact": "Compact",
+  "clear": "Clear",
+  "confirmClear": {
+    "title": "Clear messages?",
+    "description": "This will permanently delete all messages in {{channel}} / {{key}}. This action cannot be undone.",
+    "cancel": "Cancel",
+    "confirm": "Clear"
+  },
+  "dialog": {
+    "title": "Messages — {{name}}",
+    "noMessages": "No messages found.",
+    "summary": "Summary"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/providers.json b/ui/web/src/i18n/locales/en/providers.json
new file mode 100644
index 00000000..5491b713
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/providers.json
@@ -0,0 +1,115 @@
+{
+  "title": "Providers",
+  "description": "Manage LLM providers",
+  "addProvider": "Add Provider",
+  "searchPlaceholder": "Search providers...",
+  "emptyTitle": "No providers",
+  "emptyDescription": "Add your first LLM provider to get started.",
+  "noMatchTitle": "No matching providers",
+  "noMatchDescription": "Try a different search term.",
+  "columns": {
+    "name": "Name",
+    "type": "Type",
+    "apiBase": "API Base",
+    "apiKey": "API Key",
+    "status": "Status",
+    "actions": "Actions"
+  },
+  "apiKey": {
+    "oauthToken": "OAuth Token",
+    "notSet": "Not set"
+  },
+  "form": {
+    "createTitle": "Add Provider",
+    "editTitle": "Edit Provider",
+    "name": "Name *",
+    "namePlaceholder": "e.g. openrouter",
+    "nameHint": "Lowercase, numbers, hyphens",
+    "displayName": "Display Name",
+    "displayNamePlaceholder": "OpenRouter",
+    "providerType": "Provider Type *",
+    "apiKey": "API Key",
+    "apiKeyPlaceholder": "sk-...",
+    "apiKeyEditPlaceholder": "Leave as-is or enter new key",
+    "apiKeySetHint": "API key is set. Clear and type a new value to change it.",
+    "apiBase": "API Base URL",
+    "enabled": "Enabled",
+    "cancel": "Cancel",
+    "close": "Close",
+    "create": "Create",
+    "save": "Save",
+    "update": "Update",
+    "saving": "Saving...",
+    "creating": "Creating...",
+    "alreadyAdded": "(already added)",
+    "nameFixed": "Name",
+    "configure": "Configure an LLM provider connection.",
+    "lowercaseHint": "Lowercase, numbers, hyphens"
+  },
+  "delete": {
+    "title": "Delete Provider",
+    "description": "Are you sure you want to delete \"{{name}}\"? This action cannot be undone.",
+    "confirmLabel": "Delete"
+  },
+  "types": {
+    "anthropic_native": "Anthropic",
+    "openai_compat": "OpenAI Compat",
+    "gemini_native": "Gemini",
+    "openrouter": "OpenRouter",
+    "groq": "Groq",
+    "deepseek": "DeepSeek",
+    "mistral": "Mistral",
+    "xai": "xAI",
+    "minimax_native": "MiniMax",
+    "cohere": "Cohere",
+    "perplexity": "Perplexity",
+    "chatgpt_oauth": "ChatGPT (OAuth)",
+    "yescale": "YesScale"
+  },
+  "oauth": {
+    "checkingStatus": "Checking authentication status...",
+    "authSuccessful": "Authentication successful!",
+    "activeProvider": "Provider",
+    "closingIn": "is now active. Closing in {{count}}s...",
+    "authenticated": "Authenticated — provider",
+    "active": "active",
+    "modelPrefixHint": "Use model prefix",
+    "modelPrefixExample": "in agent config (e.g. openai-codex/gpt-4o). Token refreshes automatically.",
+    "removeToken": "Remove Token",
+    "signInDesc": "Sign in with your ChatGPT account to use your subscription's models without a separate API key.",
+    "waiting": "Waiting for authentication... Complete sign-in in the opened window.",
+    "remoteVpsHint": "After signing in, your browser will try to open",
+    "remoteVpsError": "and show a \"Can't reach this page\" error. That's normal — copy the full URL from the browser address bar and paste it below.",
+    "pasteUrlPlaceholder": "http://localhost:1455/auth/callback?code=...&state=...",
+    "submit": "Submit",
+    "signInWithChatGPT": "Sign in with ChatGPT",
+    "starting": "Starting...",
+    "remoteVps": "Remote/VPS?",
+    "loggedOut": "Logged out",
+    "loggedOutDesc": "OpenAI OAuth token removed",
+    "oauthFailed": "OAuth failed",
+    "exchangeFailed": "Exchange failed"
+  },
+  "cli": {
+    "description": "Claude CLI uses your local",
+    "descriptionSuffix": "binary. No API key needed.",
+    "checkingAuth": "Checking authentication...",
+    "authenticatedAs": "Authenticated as",
+    "switchAccount": "Switch account?",
+    "switchAccountInstructions": "Run on the server terminal:",
+    "switchAccountRecheck": "Then click",
+    "switchAccountRecheckSuffix": "to re-check.",
+    "notAuthenticated": "Not authenticated",
+    "runOnServer": "Run on the server terminal:",
+    "recheckButton": "Re-check"
+  },
+  "toast": {
+    "created": "Provider created",
+    "createdDesc": "{{name}} has been added",
+    "updated": "Provider updated",
+    "deleted": "Provider deleted",
+    "failedCreate": "Failed to create provider",
+    "failedUpdate": "Failed to update provider",
+    "failedDelete": "Failed to delete provider"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/sessions.json b/ui/web/src/i18n/locales/en/sessions.json
new file mode 100644
index 00000000..78a0f0b3
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/sessions.json
@@ -0,0 +1,34 @@
+{
+  "title": "Sessions",
+  "description": "Browse conversation sessions",
+  "searchPlaceholder": "Search sessions...",
+  "emptyTitle": "No sessions yet",
+  "emptyDescription": "Sessions will appear here once you start chatting.",
+  "noMatchTitle": "No matching sessions",
+  "noMatchDescription": "Try a different search term.",
+  "columns": {
+    "session": "Session",
+    "agent": "Agent",
+    "channel": "Channel",
+    "messages": "Messages",
+    "updated": "Updated"
+  },
+  "detail": {
+    "reset": "Reset",
+    "delete": "Delete",
+    "deleteTitle": "Delete Session",
+    "deleteDescription": "This will permanently delete all messages in this session.",
+    "resetTitle": "Reset Session",
+    "resetDescription": "This will clear all messages but keep the session.",
+    "confirmDelete": "Delete",
+    "confirmReset": "Reset",
+    "noMessages": "No messages in this session",
+    "summary": "Summary",
+    "showMore": "Show more",
+    "showLess": "Show less",
+    "showDetails": "show details",
+    "hide": "hide",
+    "systemMessage": "System Message",
+    "messages": "messages"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/setup.json b/ui/web/src/i18n/locales/en/setup.json
new file mode 100644
index 00000000..d1ff08ea
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/setup.json
@@ -0,0 +1,102 @@
+{
+  "layout": {
+    "subtitle": "Let's get your gateway up and running"
+  },
+  "steps": {
+    "provider": "Provider",
+    "model": "Model",
+    "agent": "Agent",
+    "channel": "Channel",
+    "channelOptional": "(Optional)"
+  },
+  "complete": {
+    "title": "Setup Complete!",
+    "ready": "Your system is ready to go!",
+    "description": "Provider, agent, and channel have been configured. You can manage them anytime from the dashboard.",
+    "goToDashboard": "Go to Dashboard"
+  },
+  "provider": {
+    "title": "Configure LLM Provider",
+    "descriptionCli": "Connect using your local Claude CLI installation. No API key needed.",
+    "description": "Connect to an AI provider to power your agents. You'll need an API key.",
+    "providerType": "Provider Type",
+    "providerTypeHint": "The LLM service you want to connect. OpenRouter is recommended for access to multiple models.",
+    "name": "Name",
+    "nameHint": "Internal identifier for this provider. Auto-generated from provider type.",
+    "apiKey": "API Key *",
+    "apiKeyHint": "Your provider's secret key. Encrypted server-side and never exposed in API responses.",
+    "apiBase": "API Base URL",
+    "apiBaseHint": "The endpoint URL for API requests. Auto-filled based on provider type. Override only if using a custom proxy.",
+    "creating": "Creating...",
+    "create": "Create Provider",
+    "errors": {
+      "apiKeyRequired": "API key is required",
+      "failedCreate": "Failed to create provider"
+    }
+  },
+  "model": {
+    "title": "Select & Verify Model",
+    "description": "Choose a model and verify that your provider connection works.",
+    "provider": "Provider:",
+    "model": "Model *",
+    "modelHint": "The AI model to use. Select from the list or type a model ID manually if not listed.",
+    "loadingModels": "Loading models...",
+    "selectModel": "Select or type a model ID",
+    "noModelsHint": "This provider doesn't list models — type the model ID manually.",
+    "verified": "Verified",
+    "verify": "Verify",
+    "verifying": "Verifying...",
+    "continue": "Continue",
+    "modelVerified": "Model verified",
+    "modelVerifiedDesc": "{{model}} is working correctly",
+    "verificationFailed": "Verification failed. Check your API key and model."
+  },
+  "agent": {
+    "title": "Create Your First Agent",
+    "description": "An agent is your AI assistant. Customize its name and personality.",
+    "provider": "Provider:",
+    "model": "Model:",
+    "displayName": "Display Name",
+    "displayNameHint": "Will be auto-generated during summoning based on the agent personality.",
+    "agentKey": "Agent Key",
+    "agentKeyHint": "Unique identifier for the agent. Lowercase letters, numbers, and hyphens only.",
+    "agentKeyPlaceholder": "my-agent",
+    "personality": "Agent Personality",
+    "personalityHint": "Describe your agent's role and behavior. AI will generate context files from this during summoning.",
+    "personalityPlaceholder": "Describe your agent's personality, purpose, and behavior...",
+    "personalityHintBottom": "Customize this prompt to shape your agent's personality and expertise.",
+    "selfEvolve": "Self-Evolution",
+    "selfEvolveDesc": "Allow agent to evolve its communication style over time via SOUL.md",
+    "creating": "Creating...",
+    "create": "Create Agent",
+    "summoningFailed": "Summoning failed. Please adjust your settings and try again.",
+    "errors": {
+      "noProvider": "No provider available",
+      "failedCreate": "Failed to create agent"
+    }
+  },
+  "channel": {
+    "title": "Connect a Channel",
+    "description": "Connect a messaging platform to your agent. You can always add channels later.",
+    "skip": "Skip",
+    "skipFinish": "Skip & Finish",
+    "agent": "Agent:",
+    "channelType": "Channel Type",
+    "channelTypeHint": "The messaging platform to connect. E.g. Telegram, Discord, Zalo.",
+    "name": "Name",
+    "nameHint": "Internal identifier for this channel instance. Auto-generated from channel type.",
+    "namePlaceholder": "my-telegram",
+    "displayName": "Display Name",
+    "displayNameHint": "A friendly name shown in the UI. Optional.",
+    "displayNamePlaceholder": "Sales Bot",
+    "credentials": "Credentials",
+    "credentialsHint": "Encrypted server-side. Never returned in API responses.",
+    "creating": "Creating...",
+    "create": "Create Channel",
+    "errors": {
+      "noAgent": "No agent available",
+      "requiredFields": "Required: {{fields}}",
+      "failedCreate": "Failed to create channel"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/sidebar.json b/ui/web/src/i18n/locales/en/sidebar.json
new file mode 100644
index 00000000..c1f05979
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/sidebar.json
@@ -0,0 +1,34 @@
+{
+  "groups": {
+    "core": "Core",
+    "management": "Management",
+    "monitoring": "Monitoring",
+    "system": "System"
+  },
+  "nav": {
+    "overview": "Overview",
+    "chat": "Chat",
+    "agents": "Agents",
+    "agentTeams": "Agent Teams",
+    "sessions": "Sessions",
+    "pendingMessages": "Pending Messages",
+    "channels": "Channels",
+    "skills": "Skills",
+    "cron": "Cron",
+    "customTools": "Custom Tools",
+    "builtinTools": "Built-in Tools",
+    "mcpServers": "MCP Servers",
+    "memory": "Memory",
+    "traces": "Traces",
+    "realtimeEvents": "Realtime Events",
+    "delegations": "Delegations",
+    "usage": "Usage",
+    "logs": "Logs",
+    "storage": "Storage",
+    "providers": "Providers",
+    "config": "Config",
+    "approvals": "Approvals",
+    "nodes": "Nodes",
+    "tts": "TTS"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/skills.json b/ui/web/src/i18n/locales/en/skills.json
new file mode 100644
index 00000000..d6063e69
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/skills.json
@@ -0,0 +1,55 @@
+{
+  "title": "Skills",
+  "description": "Manage agent skills and capabilities",
+  "searchPlaceholder": "Search skills...",
+  "emptyTitle": "No skills",
+  "emptyDescription": "No skills have been registered yet.",
+  "noMatchTitle": "No matching skills",
+  "noMatchDescription": "Try a different search term.",
+  "columns": {
+    "name": "Name",
+    "description": "Description",
+    "source": "Source",
+    "visibility": "Visibility",
+    "actions": "Actions"
+  },
+  "noDescription": "No description",
+  "delete": {
+    "title": "Delete Skill",
+    "description": "Are you sure you want to delete \"{{name}}\"? This action cannot be undone.",
+    "confirmLabel": "Delete"
+  },
+  "upload": {
+    "title": "Upload Skill",
+    "description": "Upload a ZIP file containing a SKILL.md at the root with YAML frontmatter (name, description, slug).",
+    "button": "Upload",
+    "uploading": "Uploading...",
+    "dropOrClick": "Click or drag & drop a .zip file",
+    "dropHere": "Drop .zip file here",
+    "onlyZip": "Only .zip files are accepted",
+    "cancel": "Cancel"
+  },
+  "edit": {
+    "title": "Edit Skill",
+    "name": "Name",
+    "description": "Description",
+    "visibility": "Visibility",
+    "tags": "Tags",
+    "addTag": "Add tag...",
+    "add": "Add",
+    "cancel": "Cancel",
+    "save": "Save",
+    "saving": "Saving...",
+    "privateOption": "Private (owner only)",
+    "internalOption": "Internal (granted agents/users)",
+    "publicOption": "Public (all agents)"
+  },
+  "detail": {
+    "title": "Skill Detail",
+    "content": "Content",
+    "files": "Files",
+    "version": "Version:",
+    "current": "(current)",
+    "noContent": "No content available."
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/storage.json b/ui/web/src/i18n/locales/en/storage.json
new file mode 100644
index 00000000..5df503ba
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/storage.json
@@ -0,0 +1,14 @@
+{
+  "title": "Storage",
+  "description": "Workspace file browser",
+  "descriptionWithPath": "{{path}} — {{size}}",
+  "delete": {
+    "fileTitle": "Delete file",
+    "folderTitle": "Delete folder",
+    "description": "Are you sure you want to delete {{name}}?",
+    "folderWarning": " All contents will be removed recursively.",
+    "undone": " This action cannot be undone.",
+    "deleting": "Deleting...",
+    "confirmLabel": "Delete"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/teams.json b/ui/web/src/i18n/locales/en/teams.json
new file mode 100644
index 00000000..8682acd0
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/teams.json
@@ -0,0 +1,150 @@
+{
+  "title": "Teams",
+  "description": "Manage your agent teams",
+  "createTeam": "Create Team",
+  "searchPlaceholder": "Search teams...",
+  "emptyTitle": "No teams yet",
+  "emptyDescription": "Create your first team to get started.",
+  "noMatchTitle": "No matching teams",
+  "noMatchDescription": "Try a different search term.",
+  "delete": {
+    "title": "Delete Team",
+    "description": "Are you sure you want to delete \"{{name}}\"? This action cannot be undone.",
+    "confirmLabel": "Delete"
+  },
+  "detail": {
+    "lead": "Lead",
+    "memberCount": "{{count}} member",
+    "memberCountPlural": "{{count}} members",
+    "deleteDescription": "Are you sure you want to delete \"{{name}}\"? All members, tasks, and configuration will be permanently removed.",
+    "tabs": {
+      "tasks": "Tasks",
+      "members": "Members",
+      "delegations": "Delegations",
+      "settings": "Settings"
+    }
+  },
+  "members": {
+    "title": "Members",
+    "noMembers": "No members",
+    "addMember": "Add Member",
+    "addMemberTooltip": "Only predefined agents can be added as team members. Open agents are per-user and lack shared context needed for team collaboration.",
+    "selectAgent": "Select agent to add...",
+    "noAvailableAgents": "No available agents",
+    "searchAgents": "Search agents...",
+    "adding": "Adding...",
+    "add": "Add",
+    "removeMember": "Remove member",
+    "columns": {
+      "agent": "Agent",
+      "frontmatter": "Frontmatter",
+      "role": "Role",
+      "addedAt": "Added At",
+      "actions": "Actions"
+    }
+  },
+  "tasks": {
+    "title": "Tasks",
+    "loading": "Loading tasks...",
+    "noTasks": "No tasks yet",
+    "noTasksDescription": "Tasks are created by team agents during collaboration.",
+    "refresh": "Refresh",
+    "columns": {
+      "subject": "Subject",
+      "status": "Status",
+      "owner": "Owner",
+      "priority": "Priority",
+      "taskId": "Task ID",
+      "created": "Created",
+      "actions": "Actions"
+    },
+    "detail": {
+      "title": "Task Detail",
+      "subject": "Subject",
+      "status": "Status:",
+      "priority": "Priority:",
+      "owner": "Owner:",
+      "blockedBy": "Blocked by:",
+      "description": "Description",
+      "result": "Result",
+      "created": "Created:",
+      "updated": "Updated:",
+      "taskId": "Task ID:",
+      "noDescription": "No description",
+      "noResult": "No result yet"
+    }
+  },
+  "delegations": {
+    "noTitle": "No delegations",
+    "noDescription": "No delegation records found for this team.",
+    "refresh": "Refresh",
+    "columns": {
+      "sourceTarget": "Source / Target",
+      "task": "Task",
+      "status": "Status",
+      "duration": "Duration",
+      "time": "Time"
+    }
+  },
+  "settings": {
+    "title": "Team Settings",
+    "name": "Name",
+    "displayName": "Display Name",
+    "description": "Description",
+    "leadAgent": "Lead Agent",
+    "status": "Status",
+    "active": "Active",
+    "inactive": "Inactive",
+    "save": "Save Settings",
+    "saving": "Saving...",
+    "saved": "Saved",
+    "failedSave": "Failed to save",
+    "userAccessControl": "User Access Control",
+    "allowedUsers": "Allowed Users",
+    "allowedUsersHint": "If set, only these users can trigger team workflows. Empty = all allowed.",
+    "deniedUsers": "Denied Users",
+    "deniedUsersHint": "Always blocked, overrides allow list.",
+    "channelRestrictions": "Channel Restrictions",
+    "allowedChannels": "Allowed Channels",
+    "allowedChannelsHint": "If set, only these channels can activate team workflows. Empty = all allowed.",
+    "deniedChannels": "Denied Channels",
+    "deniedChannelsHint": "Messages from these channels are always blocked.",
+    "notifications": "Notifications",
+    "progressNotifications": "Progress notifications",
+    "progressNotificationsHint": "Send periodic \"Your team is working on it...\" messages to chat during async delegations.",
+    "searchUsers": "Search users...",
+    "selectChannel": "Select channel..."
+  },
+  "create": {
+    "title": "Create Team",
+    "name": "Name *",
+    "namePlaceholder": "e.g. Research Team",
+    "nameHint": "Lowercase letters, numbers, hyphens",
+    "description": "Description",
+    "descriptionPlaceholder": "Optional team description...",
+    "leadAgent": "Lead Agent *",
+    "selectLeadAgent": "Select lead agent...",
+    "loadingAgents": "Loading agents...",
+    "noActiveAgents": "No active agents found. Create agents first.",
+    "members": "Members",
+    "membersTooltip": "Only predefined agents can be added as team members. Open agents are per-user and lack shared context needed for team collaboration.",
+    "searchMembers": "Search and add members...",
+    "displayName": "Display Name",
+    "displayNamePlaceholder": "Support Team",
+    "cancel": "Cancel",
+    "create": "Create",
+    "creating": "Creating..."
+  },
+  "toast": {
+    "created": "Team created",
+    "deleted": "Team deleted",
+    "updated": "Team updated",
+    "memberAdded": "Member added",
+    "memberRemoved": "Member removed",
+    "failedCreate": "Failed to create team",
+    "failedDelete": "Failed to delete team",
+    "failedUpdate": "Failed to update team",
+    "failedAddMember": "Failed to add member",
+    "failedRemoveMember": "Failed to remove member"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/tools.json b/ui/web/src/i18n/locales/en/tools.json
new file mode 100644
index 00000000..19b9e39e
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/tools.json
@@ -0,0 +1,156 @@
+{
+  "custom": {
+    "title": "Custom Tools",
+    "description": "Manage custom shell-based tools for agents",
+    "createTool": "Create Tool",
+    "searchPlaceholder": "Search tools...",
+    "emptyTitle": "No custom tools",
+    "emptyDescription": "Create your first custom tool to get started.",
+    "noMatchTitle": "No matching tools",
+    "noMatchDescription": "Try a different search term.",
+    "noDescription": "No description",
+    "columns": {
+      "name": "Name",
+      "description": "Description",
+      "scope": "Scope",
+      "enabled": "Enabled",
+      "timeout": "Timeout",
+      "actions": "Actions"
+    },
+    "scope": {
+      "agent": "Agent",
+      "global": "Global"
+    },
+    "delete": {
+      "title": "Delete Custom Tool",
+      "description": "Are you sure you want to delete \"{{name}}\"? This action cannot be undone.",
+      "confirmLabel": "Delete"
+    },
+    "form": {
+      "createTitle": "Create Custom Tool",
+      "editTitle": "Edit Tool",
+      "name": "Name *",
+      "namePlaceholder": "my-tool",
+      "nameHint": "Lowercase letters, numbers, and hyphens only",
+      "description": "Description",
+      "descriptionPlaceholder": "What this tool does...",
+      "command": "Command *",
+      "commandHint": "Shell template. Use {{.key}} for parameter placeholders.",
+      "parameters": "Parameters (JSON Schema)",
+      "workingDir": "Working Directory",
+      "workingDirPlaceholder": "/path/to/dir",
+      "timeout": "Timeout (seconds)",
+      "agentId": "Agent ID (optional)",
+      "agentIdPlaceholder": "Leave blank for global scope",
+      "enabled": "Enabled",
+      "cancel": "Cancel",
+      "create": "Create",
+      "update": "Update",
+      "saving": "Saving...",
+      "errors": {
+        "nameRequired": "Name and command are required",
+        "nameSlug": "Name must be a valid slug (lowercase letters, numbers, hyphens only)",
+        "invalidJson": "Parameters must be valid JSON"
+      }
+    },
+    "toast": {
+      "created": "Tool created",
+      "createdDesc": "{{name}} has been added",
+      "updated": "Tool updated",
+      "deleted": "Tool deleted",
+      "failedCreate": "Failed to create tool",
+      "failedUpdate": "Failed to update tool",
+      "failedDelete": "Failed to delete tool"
+    }
+  },
+  "builtin": {
+    "title": "Built-in Tools",
+    "description": "Manage system built-in tools. Enable/disable or configure settings globally.",
+    "searchPlaceholder": "Search tools...",
+    "emptyTitle": "No built-in tools",
+    "emptyDescription": "No built-in tools have been seeded yet.",
+    "noMatchTitle": "No matching tools",
+    "noMatchDescription": "Try a different search term.",
+    "toolCount": "{{count}} tool",
+    "toolCountPlural": "{{count}} tools",
+    "categoryCount": "{{count}} categories",
+    "requires": "req",
+    "requiresTooltip": "Requires: {{list}}",
+    "settings": "Settings",
+    "configuredVia": "Configured via the Config page",
+    "categories": {
+      "filesystem": "Filesystem",
+      "runtime": "Runtime",
+      "web": "Web",
+      "memory": "Memory",
+      "media": "Media",
+      "browser": "Browser",
+      "sessions": "Sessions",
+      "messaging": "Messaging",
+      "scheduling": "Scheduling",
+      "subagents": "Agents",
+      "skills": "Skills",
+      "delegation": "Delegation",
+      "teams": "Teams"
+    },
+    "settingsDialog": {
+      "title": "Settings — {{name}}",
+      "cancel": "Cancel",
+      "save": "Save",
+      "saving": "Saving...",
+      "noFields": "No configurable settings for this tool.",
+      "toast": {
+        "saved": "Settings saved",
+        "failed": "Failed to save settings"
+      }
+    },
+    "jsonDialog": {
+      "title": "Settings: {{name}}",
+      "description": "Edit tool-specific settings as JSON. Changes take effect immediately after saving.",
+      "formatJson": "Format JSON",
+      "invalidJsonSyntax": "Invalid JSON syntax",
+      "invalidJson": "Invalid JSON",
+      "cannotFormat": "Cannot format: invalid JSON",
+      "cancel": "Cancel",
+      "save": "Save",
+      "saving": "Saving..."
+    },
+    "kgSettings": {
+      "title": "Knowledge Graph Settings",
+      "description": "Configure entity extraction from memory writes. Requires a provider/model capable of structured JSON output.",
+      "extractionProvider": "Extraction Provider",
+      "extractionModel": "Extraction Model",
+      "providerTip": "LLM provider used to extract entities and relations from text.",
+      "modelTip": "Model ID for extraction. Should support structured JSON output.",
+      "minConfidence": "Min Confidence",
+      "minConfidenceHint": "Entities below this confidence score are discarded (0.0–1.0).",
+      "autoExtract": "Auto-extract on memory write",
+      "autoExtractHint": "Automatically extract entities when agents write to memory files.",
+      "cancel": "Cancel",
+      "save": "Save",
+      "saving": "Saving..."
+    },
+    "mediaChain": {
+      "providerChainSuffix": "— Provider Chain",
+      "description": "Configure and order provider fallbacks. Drag to reorder — the first enabled provider is tried first.",
+      "newProvider": "New Provider",
+      "provider": "Provider",
+      "model": "Model",
+      "selectProvider": "Select provider",
+      "loadingModels": "Loading...",
+      "selectModel": "Select model",
+      "timeout": "Timeout",
+      "retries": "Retries",
+      "settings": "Settings",
+      "noProviders": "No providers configured. Add one below.",
+      "addProvider": "Add Provider",
+      "cancel": "Cancel",
+      "save": "Save",
+      "saving": "Saving..."
+    },
+    "toast": {
+      "toggled": "Tool updated",
+      "failedToggle": "Failed to update tool"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/topbar.json b/ui/web/src/i18n/locales/en/topbar.json
new file mode 100644
index 00000000..9f9d71aa
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/topbar.json
@@ -0,0 +1,16 @@
+{
+  "expandSidebar": "Expand sidebar",
+  "collapseSidebar": "Collapse sidebar",
+  "openMenu": "Open menu",
+  "toggleTheme": "Toggle theme",
+  "logout": "Logout",
+  "language": "Language",
+  "pairingRequests": "Pairing requests",
+  "pendingPairingRequest": "{{count}} pending pairing request",
+  "pendingPairingRequests": "{{count}} pending pairing requests",
+  "languages": {
+    "en": "English",
+    "vi": "Tiếng Việt",
+    "zh": "中文"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/traces.json b/ui/web/src/i18n/locales/en/traces.json
new file mode 100644
index 00000000..46129db1
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/traces.json
@@ -0,0 +1,49 @@
+{
+  "title": "Traces",
+  "description": "LLM call traces and performance data",
+  "filterPlaceholder": "Filter by agent ID...",
+  "filter": "Filter",
+  "emptyTitle": "No traces",
+  "emptyDescription": "No traces found. Traces are recorded when agents process requests.",
+  "columns": {
+    "name": "Name",
+    "status": "Status",
+    "duration": "Duration",
+    "tokens": "Tokens",
+    "spans": "Spans",
+    "time": "Time"
+  },
+  "unnamed": "Unnamed",
+  "cached": "cached",
+  "detail": {
+    "title": "Trace Detail",
+    "copyTraceId": "Copy trace ID",
+    "notFound": "Trace not found.",
+    "name": "Name:",
+    "status": "Status:",
+    "duration": "Duration:",
+    "channel": "Channel:",
+    "tokens": "Tokens:",
+    "spans": "Spans:",
+    "started": "Started:",
+    "delegatedFrom": "Delegated from:",
+    "input": "Input",
+    "output": "Output",
+    "spansCount": "Spans ({{count}})",
+    "llmCalls": "LLM",
+    "toolCalls": "tool"
+  },
+  "span": {
+    "model": "Model:",
+    "tokens": "Tokens:",
+    "input": "Input:",
+    "output": "Output:",
+    "cacheRead": "read",
+    "cacheWrite": "write",
+    "thinking": "thinking",
+    "cached": "cached"
+  },
+  "toast": {
+    "failedLoad": "Failed to load traces"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/tts.json b/ui/web/src/i18n/locales/en/tts.json
new file mode 100644
index 00000000..bf1fb98a
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/tts.json
@@ -0,0 +1,71 @@
+{
+  "title": "Text-to-Speech",
+  "description": "Configure TTS providers and auto-apply settings",
+  "save": "Save",
+  "saving": "Saving...",
+  "saveChanges": "Save Changes",
+  "status": {
+    "title": "Status",
+    "configured": "Configured",
+    "disabled": "Disabled",
+    "noProvider": "No TTS provider configured",
+    "activeProvider": "Primary provider: {{provider}}, Auto: {{auto}}"
+  },
+  "general": {
+    "title": "General Settings",
+    "primaryProvider": "Primary Provider",
+    "autoApplyMode": "Auto-Apply Mode",
+    "replyMode": "Reply Mode",
+    "maxTextLength": "Max Text Length",
+    "timeout": "Timeout (ms)"
+  },
+  "providers": {
+    "none": "None (Disabled)",
+    "openai": "OpenAI",
+    "elevenlabs": "ElevenLabs",
+    "edge": "Edge (Free)",
+    "minimax": "MiniMax"
+  },
+  "autoModes": {
+    "off": "Off",
+    "offDesc": "Agent can use TTS tool manually",
+    "always": "Always",
+    "alwaysDesc": "All replies get audio",
+    "inbound": "Inbound",
+    "inboundDesc": "Only when user sends voice/audio",
+    "tagged": "Tagged",
+    "taggedDesc": "Only when reply contains [[tts]] tag"
+  },
+  "replyModes": {
+    "final": "Final only",
+    "finalDesc": "Only final replies",
+    "all": "All",
+    "allDesc": "All replies including tool/block"
+  },
+  "providerSettings": "{{provider}} Settings",
+  "openai": {
+    "apiKey": "API Key",
+    "apiBase": "API Base URL",
+    "model": "Model",
+    "voice": "Voice"
+  },
+  "elevenlabs": {
+    "apiKey": "API Key",
+    "baseUrl": "Base URL",
+    "voiceId": "Voice ID",
+    "modelId": "Model ID"
+  },
+  "edge": {
+    "voice": "Voice",
+    "speechRate": "Speech Rate",
+    "hint": "Edge TTS is free and requires no API key. Install with: pip install edge-tts"
+  },
+  "minimax": {
+    "apiKey": "API Key",
+    "groupId": "Group ID *",
+    "groupIdPlaceholder": "Required for MiniMax",
+    "apiBase": "API Base",
+    "model": "Model",
+    "voiceId": "Voice ID"
+  }
+}
diff --git a/ui/web/src/i18n/locales/en/usage.json b/ui/web/src/i18n/locales/en/usage.json
new file mode 100644
index 00000000..60754f1b
--- /dev/null
+++ b/ui/web/src/i18n/locales/en/usage.json
@@ -0,0 +1,21 @@
+{
+  "title": "Usage",
+  "description": "Token usage and costs by agent",
+  "emptyTitle": "No usage data",
+  "emptyDescription": "Usage data will appear here after agents process requests.",
+  "summary": {
+    "sessions": "{{count}} sessions",
+    "inputTokens": "Input tokens",
+    "outputTokens": "Output tokens",
+    "total": "Total"
+  },
+  "recentRecords": "Recent Records",
+  "columns": {
+    "agent": "Agent",
+    "model": "Model",
+    "provider": "Provider",
+    "input": "Input",
+    "output": "Output",
+    "total": "Total"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/agents.json b/ui/web/src/i18n/locales/vi/agents.json
new file mode 100644
index 00000000..60ff5d14
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/agents.json
@@ -0,0 +1,342 @@
+{
+  "title": "Agent",
+  "description": "Quản lý các agent AI của bạn",
+  "createAgent": "Tạo agent",
+  "searchPlaceholder": "Tìm kiếm agent...",
+  "emptyTitle": "Chưa có agent nào",
+  "emptyDescription": "Tạo agent đầu tiên để bắt đầu.",
+  "noMatchTitle": "Không tìm thấy agent phù hợp",
+  "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+  "card": {
+    "unnamedAgent": "Agent chưa đặt tên",
+    "summoning": "Đang triệu hồi...",
+    "summonFailed": "Thất bại",
+    "resummon": "Triệu hồi lại",
+    "delete": "Xóa",
+    "predefinedTooltip": "Tệp ngữ cảnh dùng chung (SOUL.md, IDENTITY.md, AGENTS.md) với USER.md riêng cho mỗi người dùng.",
+    "openTooltip": "Mỗi người dùng có bộ tệp ngữ cảnh riêng đầy đủ.",
+    "evolving": "Đang tiến hóa",
+    "static": "Tĩnh",
+    "evolvingTooltip": "Agent có thể tự tiến hóa phong cách giao tiếp (SOUL.md). Nhận dạng và quy trình làm việc giữ nguyên.",
+    "staticTooltip": "Phong cách agent là tĩnh. Bật Tự Tiến Hóa trong cài đặt để cho phép thích nghi phong cách."
+  },
+  "delete": {
+    "title": "Xóa agent",
+    "description": "Xóa vĩnh viễn agent này, tất cả tệp ngữ cảnh, session và cấu hình. Hành động này không thể hoàn tác.",
+    "detailDescription": "Bạn có chắc chắn muốn xóa \"{{name}}\"? Tất cả tệp ngữ cảnh, session và cấu hình sẽ bị xóa vĩnh viễn.",
+    "confirmLabel": "Xóa",
+    "defaultCannotDelete": "Agent mặc định không thể bị xóa."
+  },
+  "create": {
+    "title": "Tạo agent",
+    "displayName": "Tên hiển thị *",
+    "displayNamePlaceholder": "Agent của tôi",
+    "agentKey": "Khóa agent *",
+    "agentKeyPlaceholder": "vd: my-agent",
+    "agentKeyHint": "Chữ thường, số, dấu gạch ngang",
+    "provider": "Provider *",
+    "selectProvider": "Chọn provider",
+    "model": "Model *",
+    "enterOrSelectModel": "Nhập hoặc chọn model",
+    "loadingModels": "Đang tải model...",
+    "check": "Kiểm tra",
+    "checking": "Đang kiểm tra...",
+    "modelVerified": "Model đã xác minh",
+    "verificationFailed": "Xác minh thất bại",
+    "noModelsHint": "Provider này không liệt kê model — nhập ID model thủ công.",
+    "agentType": "Loại agent",
+    "open": "Mở",
+    "openSubLabel": "Ngữ cảnh riêng cho mỗi người dùng",
+    "predefined": "Định sẵn",
+    "predefinedSubLabel": "Cấu hình ở cấp agent",
+    "describeAgent": "Mô tả agent của bạn",
+    "descriptionPlaceholder": "Mô tả tính cách, mục đích và hành vi của agent...",
+    "descriptionHint": "AI sẽ tự động tạo tệp ngữ cảnh cho agent từ mô tả này. Để trống để bắt đầu với mẫu có sẵn.",
+    "selfEvolution": "Tự tiến hóa",
+    "selfEvolutionHint": "Cho phép agent tiến hóa phong cách và giọng điệu theo thời gian qua SOUL.md",
+    "cancel": "Hủy",
+    "create": "Tạo",
+    "creating": "Đang tạo...",
+    "checkAndCreate": "Kiểm tra & Tạo",
+    "failedToCreate": "Tạo agent thất bại"
+  },
+  "detail": {
+    "tabs": {
+      "general": "Chung",
+      "config": "Cấu hình",
+      "files": "Tệp",
+      "shares": "Chia sẻ",
+      "links": "Liên kết",
+      "skills": "Skill",
+      "instances": "Phiên bản người dùng"
+    },
+    "summonFailed": "Triệu hồi thất bại",
+    "evolving": "Đang tiến hóa",
+    "static": "Tĩnh",
+    "evolvingTooltipDetail": "Agent có thể tự tiến hóa phong cách giao tiếp (SOUL.md). Nhận dạng và quy trình làm việc giữ nguyên.",
+    "staticTooltipDetail": "Phong cách agent là tĩnh. Bật Tự Tiến Hóa trong tab Chung để cho phép thích nghi phong cách."
+  },
+  "general": {
+    "selfEvolution": "Tự tiến hóa",
+    "selfEvolutionLabel": "Cho phép agent tiến hóa phong cách giao tiếp",
+    "selfEvolutionHint": "Khi được bật, agent có thể cập nhật SOUL.md để tinh chỉnh giọng điệu, từ vựng và phong cách phản hồi dựa trên tương tác. Nhận dạng, tên và hướng dẫn hoạt động vẫn bị khóa.",
+    "selfEvolutionInfo": "Agent sẽ tiến hóa phong cách theo thời gian qua các cập nhật SOUL.md. Chỉ phong cách và giọng điệu bị ảnh hưởng — nhận dạng và quy tắc quy trình làm việc vẫn cố định.",
+    "saveChanges": "Lưu thay đổi",
+    "saving": "Đang lưu...",
+    "saved": "Đã lưu",
+    "failedToSave": "Lưu thất bại"
+  },
+  "identity": {
+    "title": "Nhận dạng",
+    "agentKey": "Khóa agent",
+    "agentKeyHint": "Định danh duy nhất, không thể thay đổi.",
+    "displayName": "Tên hiển thị",
+    "displayNamePlaceholder": "vd: Trợ lý của tôi",
+    "displayNameHint": "Tên thân thiện hiển thị trong giao diện. Để trống để dùng khóa agent.",
+    "expertiseSummary": "Tóm tắt chuyên môn",
+    "expertiseSummaryPlaceholder": "vd: Chiêm tinh, bói toán, tử vi, thần số học",
+    "expertiseSummaryHint": "Mô tả ngắn về chuyên môn của agent. Dùng để tìm kiếm ủy quyền.",
+    "status": "Trạng thái",
+    "active": "Hoạt động",
+    "inactive": "Không hoạt động",
+    "summonFailed": "Triệu hồi thất bại",
+    "defaultAgent": "Agent mặc định"
+  },
+  "llmConfig": {
+    "title": "Cấu hình LLM",
+    "contextWindow": "Cửa sổ ngữ cảnh",
+    "contextWindowHint": "Giới hạn token cho ngữ cảnh model.",
+    "maxToolIterations": "Số lần lặp công cụ tối đa",
+    "maxToolIterationsHint": "Số lần gọi công cụ tối đa mỗi yêu cầu."
+  },
+  "workspace": {
+    "title": "Không gian làm việc",
+    "workspacePath": "Đường dẫn không gian làm việc",
+    "workspacePathHint": "Được gán tự động khi agent được tạo. Các thư mục con theo người dùng được tạo khi chạy.",
+    "noWorkspace": "Chưa cấu hình không gian làm việc",
+    "restrictToWorkspace": "Giới hạn trong không gian làm việc",
+    "restrictToWorkspaceHint": "Giới hạn quyền truy cập tệp trong đường dẫn không gian làm việc."
+  },
+  "config": {
+    "saveConfig": "Lưu cấu hình",
+    "saving": "Đang lưu...",
+    "saved": "Đã lưu",
+    "failedToSave": "Lưu thất bại",
+    "usingGlobalDefaults": "Đang dùng mặc định toàn cục từ config.json"
+  },
+  "files": {
+    "readOnly": "Chỉ đọc",
+    "readOnlyDesc": "Chỉ chủ sở hữu agent mới có thể chỉnh sửa tệp ngữ cảnh định sẵn.",
+    "resummon": "Triệu hồi lại",
+    "editWithAi": "Chỉnh sửa với AI",
+    "resummonTitle": "Triệu hồi lại agent",
+    "resummonDesc": "Thao tác này sẽ tái tạo SOUL.md, IDENTITY.md và tùy chọn USER_PREDEFINED.md từ đầu bằng mô tả gốc. Mọi chỉnh sửa thủ công sẽ bị ghi đè.",
+    "cancel": "Hủy",
+    "resummonConfirm": "Triệu hồi lại",
+    "summoning": "Đang triệu hồi...",
+    "selectFileToEdit": "Chọn tệp để chỉnh sửa",
+    "selectFileToView": "Chọn tệp để xem",
+    "saving": "Đang lưu...",
+    "save": "Lưu",
+    "loading": "Đang tải...",
+    "openAgentTitle": "Agent mở - Tệp ngữ cảnh riêng theo người dùng",
+    "openAgentDesc1": "Đây là agent mở. Các tệp ngữ cảnh (AGENTS.md, SOUL.md, TOOLS.md, v.v.) được cá nhân hóa cho mỗi người dùng. Chúng tự động được tạo từ mẫu khi người dùng trò chuyện lần đầu với agent này.",
+    "openAgentDesc2pre": "Các tệp cấp agent hiển thị ở đây trống vì agent mở lưu trữ tất cả ngữ cảnh theo người dùng trong bảng ",
+    "openAgentDesc2post": ".",
+    "contextFiles": "Tệp ngữ cảnh",
+    "contextFile": "Tệp ngữ cảnh",
+    "perUser": "theo người dùng",
+    "emptyFile": "trống",
+    "estTokens": "Ước {{tokens}} token"
+  },
+  "fileEditor": {
+    "editWithAi": "Chỉnh sửa với AI",
+    "editAiDescription": "Mô tả những gì bạn muốn thay đổi. AI sẽ đọc các tệp hiện tại và cập nhật chúng.",
+    "editAiPlaceholder": "vd: Làm cho agent trang trọng hơn, thêm hỗ trợ tiếng Việt, đổi tên thành Luna...",
+    "sending": "Đang gửi...",
+    "regenerate": "Tái tạo",
+    "cancel": "Hủy"
+  },
+  "shares": {
+    "grantAccess": "Cấp quyền truy cập",
+    "userId": "ID người dùng",
+    "userIdPlaceholder": "Nhập ID người dùng...",
+    "role": "Vai trò",
+    "share": "Chia sẻ",
+    "loadingShares": "Đang tải chia sẻ...",
+    "noShares": "Chưa có chia sẻ",
+    "noSharesDesc": "Chia sẻ agent này với người dùng khác bằng cách nhập ID người dùng ở trên.",
+    "user": "Người dùng",
+    "revokeTitle": "Thu hồi chia sẻ",
+    "revokeDesc": "Thu hồi quyền truy cập của người dùng \"{{userId}}\"? Họ sẽ không thể sử dụng agent này nữa.",
+    "revoke": "Thu hồi"
+  },
+  "links": {
+    "teamsHint": "Để cộng tác đa agent với theo dõi nhiệm vụ và kiểm soát chất lượng, hãy cân nhắc sử dụng Nhóm agent thay thế. Liên kết agent phù hợp nhất cho ủy quyền đơn giản 1-1 giữa hai agent.",
+    "createLink": "Tạo liên kết",
+    "targetAgent": "Agent đích",
+    "selectAgent": "Chọn hoặc tìm kiếm agent...",
+    "direction": "Hướng",
+    "description": "Mô tả",
+    "descriptionPlaceholder": "Mô tả tùy chọn của liên kết...",
+    "maxConcurrent": "Tối đa đồng thời",
+    "advancedSettings": "Cài đặt nâng cao",
+    "allowedUsers": "Người dùng được phép",
+    "allowedUsersPlaceholder": "user1, user2, ...",
+    "allowedUsersHint": "Nếu đặt, chỉ những người dùng này mới có thể kích hoạt ủy quyền. Phân cách bằng dấu phẩy.",
+    "deniedUsers": "Người dùng bị từ chối",
+    "deniedUsersPlaceholder": "user3, user4, ...",
+    "deniedUsersHint": "Những người dùng này bị chặn kích hoạt ủy quyền. Phân cách bằng dấu phẩy.",
+    "creating": "Đang tạo...",
+    "noLinks": "Chưa có liên kết agent",
+    "noLinksDesc": "Tạo liên kết để cho phép các agent ủy quyền nhiệm vụ cho nhau.",
+    "loadingLinks": "Đang tải liên kết...",
+    "columns": {
+      "target": "Đích",
+      "direction": "Hướng",
+      "status": "Trạng thái",
+      "limit": "Giới hạn"
+    },
+    "deleteTitle": "Xóa liên kết",
+    "deleteDesc": "Xóa liên kết ủy quyền đến \"{{name}}\"? Các agent sẽ không thể ủy quyền cho nhau qua liên kết này nữa.",
+    "editTitle": "Chỉnh sửa liên kết",
+    "editDescription": "Cập nhật cài đặt liên kết ủy quyền.",
+    "optionalDescription": "Mô tả tùy chọn...",
+    "allowedUsersHintShort": "Nếu đặt, chỉ những người dùng này mới có thể kích hoạt ủy quyền.",
+    "deniedUsersHintShort": "Những người dùng này bị chặn kích hoạt ủy quyền."
+  },
+  "skills": {
+    "noSkillsAvailable": "Không có skill khả dụng",
+    "noSkillsDesc": "Tải lên skill trong trang Skill để cấp cho agent.",
+    "skillsGranted": "{{granted}} trong {{total}} skill được cấp",
+    "filterSkills": "Lọc skill...",
+    "noSkillsMatch": "Không có skill nào phù hợp."
+  },
+  "instances": {
+    "loadingInstances": "Đang tải phiên bản...",
+    "noInstances": "Chưa có phiên bản người dùng.",
+    "noInstancesDesc": "Phiên bản được tạo khi người dùng tương tác với agent này.",
+    "instanceCount": "{{count}} phiên bản",
+    "instanceCount_plural": "{{count}} phiên bản",
+    "selectInstance": "Chọn một phiên bản để xem và chỉnh sửa USER.md của nó",
+    "loading": "Đang tải...",
+    "saving": "Đang lưu...",
+    "save": "Lưu",
+    "saved": "Đã lưu"
+  },
+  "summoning": {
+    "title": "Đang triệu hồi agent...",
+    "completed": "Triệu hồi hoàn tất!",
+    "failed": "Triệu hồi thất bại",
+    "agentReady": "{{name}} đã sẵn sàng!",
+    "weavingSoul": "Đang dệt linh hồn cho",
+    "wait": "Thường mất vài phút. Vui lòng chờ...",
+    "continue": "Tiếp tục",
+    "retry": "Thử lại",
+    "retrying": "Đang thử lại...",
+    "done": "xong"
+  },
+  "configSections": {
+    "subagents": {
+      "title": "Agent con",
+      "description": "Kiểm soát giới hạn sinh sản agent con và hành vi",
+      "maxConcurrent": "Tối đa đồng thời",
+      "maxSpawnDepth": "Độ sâu sinh sản tối đa",
+      "maxChildrenPerAgent": "Con tối đa mỗi agent",
+      "archiveAfter": "Lưu trữ sau (phút)",
+      "modelOverride": "Ghi đè model",
+      "inheritFromAgent": "(kế thừa từ agent)"
+    },
+    "toolPolicy": {
+      "title": "Chính sách công cụ",
+      "description": "Kiểm soát công cụ nào agent có thể sử dụng",
+      "profile": "Hồ sơ",
+      "allow": "Cho phép",
+      "deny": "Từ chối",
+      "alsoAllow": "Cũng cho phép",
+      "selectToolsAllow": "Chọn công cụ để cho phép...",
+      "selectToolsDeny": "Chọn công cụ để từ chối...",
+      "selectToolsAlsoAllow": "Chọn công cụ bổ sung..."
+    },
+    "compaction": {
+      "title": "Nén ngữ cảnh",
+      "description": "Cài đặt nén cửa sổ ngữ cảnh và xả bộ nhớ",
+      "reserveTokensFloor": "Sàn token dự trữ",
+      "maxHistoryShare": "Phần lịch sử tối đa (0-1)",
+      "minMessages": "Tin nhắn tối thiểu",
+      "keepLastMessages": "Giữ tin nhắn cuối",
+      "memoryFlush": "Xả bộ nhớ",
+      "softThreshold": "Ngưỡng mềm (token)"
+    },
+    "contextPruning": {
+      "title": "Cắt bớt ngữ cảnh",
+      "description": "Cắt bỏ kết quả công cụ cũ để tiết kiệm cửa sổ ngữ cảnh",
+      "mode": "Chế độ",
+      "keepLastAssistants": "Giữ trợ lý cuối",
+      "softTrimRatio": "Tỷ lệ cắt mềm (0-1)",
+      "hardClearRatio": "Tỷ lệ xóa cứng (0-1)",
+      "minPrunableToolChars": "Ký tự công cụ tối thiểu có thể cắt",
+      "softTrim": "Cắt mềm",
+      "maxChars": "Ký tự tối đa",
+      "headChars": "Ký tự đầu",
+      "tailChars": "Ký tự cuối",
+      "hardClear": "Xóa cứng",
+      "enabled": "Đã bật",
+      "placeholderText": "Văn bản thay thế"
+    },
+    "sandbox": {
+      "title": "Hộp cát",
+      "description": "Hộp cát Docker để cô lập thực thi code",
+      "mode": "Chế độ",
+      "workspaceAccess": "Truy cập không gian làm việc",
+      "image": "Hình ảnh",
+      "scope": "Phạm vi",
+      "timeout": "Hết giờ (giây)",
+      "memoryMb": "Bộ nhớ (MB)",
+      "cpus": "CPU",
+      "networkEnabled": "Bật mạng"
+    },
+    "memory": {
+      "title": "Bộ nhớ",
+      "description": "Tìm kiếm bộ nhớ ngữ nghĩa và cấu hình nhúng",
+      "embeddingProvider": "Provider nhúng",
+      "embeddingModel": "Model nhúng",
+      "maxResults": "Kết quả tối đa",
+      "maxChunkLen": "Độ dài chunk tối đa",
+      "vectorWeight": "Trọng số vector",
+      "textWeight": "Trọng số văn bản"
+    },
+    "thinking": {
+      "title": "Suy nghĩ mở rộng",
+      "description": "Cho phép model suy luận trước khi phản hồi. Cấp độ cao hơn dùng nhiều token hơn nhưng cho kết quả tốt hơn với tác vụ phức tạp.",
+      "thinkingLevel": "Cấp độ suy nghĩ",
+      "off": "Tắt",
+      "offDesc": "Không có suy nghĩ mở rộng",
+      "low": "Thấp",
+      "lowDesc": "~4K ngân sách token",
+      "medium": "Trung bình",
+      "mediumDesc": "~10-16K ngân sách token",
+      "high": "Cao",
+      "highDesc": "~32K ngân sách token"
+    },
+    "qualityGates": {
+      "title": "Cổng chất lượng",
+      "description": "Xác thực đầu ra ủy quyền trước khi trả về cho người gọi",
+      "noGates": "Chưa cấu hình cổng chất lượng. Nhấp \"Thêm cổng\" để tạo.",
+      "addGate": "Thêm cổng",
+      "gateNumber": "Cổng #{{number}}",
+      "type": "Loại",
+      "reviewerAgentKey": "Khóa agent đánh giá",
+      "command": "Lệnh",
+      "blockOnFailure": "Chặn khi thất bại",
+      "maxRetries": "Số lần thử lại tối đa",
+      "timeout": "Hết giờ (giây)"
+    },
+    "otherConfig": {
+      "title": "Cấu hình khác",
+      "description": "Cấu hình JSON bổ sung cho các cài đặt nâng cao không được đề cập trong các mục khác",
+      "formatJson": "Định dạng JSON",
+      "invalidJson": "Cú pháp JSON không hợp lệ"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/approvals.json b/ui/web/src/i18n/locales/vi/approvals.json
new file mode 100644
index 00000000..b3ee67fb
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/approvals.json
@@ -0,0 +1,23 @@
+{
+  "title": "Phê duyệt",
+  "description": "Phê duyệt thực thi đang chờ",
+  "pending": "{{count}} đang chờ",
+  "emptyTitle": "Không có phê duyệt đang chờ",
+  "emptyDescription": "Tất cả yêu cầu thực thi đã được giải quyết. Yêu cầu mới sẽ xuất hiện ở đây theo thời gian thực.",
+  "allowOnce": "Cho phép một lần",
+  "allowAlways": "Luôn cho phép",
+  "deny": "Từ chối",
+  "confirmAllowOnce": {
+    "title": "Cho phép một lần",
+    "description": "Cho phép thực thi \"{{command}}\" từ agent \"{{agentId}}\"?"
+  },
+  "confirmAllowAlways": {
+    "title": "Luôn cho phép",
+    "description": "Luôn cho phép \"{{command}}\" cho agent \"{{agentId}}\"? Lệnh này sẽ được tự động phê duyệt trong tương lai."
+  },
+  "confirmDeny": {
+    "title": "Từ chối thực thi",
+    "description": "Từ chối yêu cầu thực thi \"{{command}}\" từ agent \"{{agentId}}\"?",
+    "confirmLabel": "Từ chối"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/channels.json b/ui/web/src/i18n/locales/vi/channels.json
new file mode 100644
index 00000000..3a0048b2
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/channels.json
@@ -0,0 +1,213 @@
+{
+  "title": "Channel",
+  "description": "Quản lý các phiên bản channel",
+  "statusDescription": "Trạng thái channel liên lạc",
+  "addChannel": "Thêm channel",
+  "refresh": "Làm mới",
+  "searchPlaceholder": "Tìm kiếm channel...",
+  "emptyTitle": "Không có channel nào",
+  "emptyDescription": "Thêm phiên bản channel đầu tiên để bắt đầu.",
+  "emptyStatusDescription": "Chưa có channel liên lạc nào được cấu hình.",
+  "noMatchTitle": "Không tìm thấy channel phù hợp",
+  "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+  "columns": {
+    "name": "Tên",
+    "type": "Loại",
+    "agent": "Agent",
+    "status": "Trạng thái",
+    "enabled": "Bật",
+    "actions": "Thao tác"
+  },
+  "status": {
+    "running": "Đang chạy",
+    "stopped": "Đã dừng"
+  },
+  "enabled": "Đã bật",
+  "disabled": "Đã tắt",
+  "actions": {
+    "reauthenticate": "Xác thực lại",
+    "authenticate": "Xác thực để khởi động channel"
+  },
+  "delete": {
+    "title": "Xóa phiên bản channel",
+    "description": "Bạn có chắc chắn muốn xóa \"{{name}}\"? Hành động này không thể hoàn tác.",
+    "confirmLabel": "Xóa"
+  },
+  "form": {
+    "createTitle": "Tạo phiên bản channel",
+    "editTitle": "Chỉnh sửa phiên bản channel",
+    "key": "Khóa *",
+    "keyPlaceholder": "my-telegram-bot",
+    "keyHint": "Slug duy nhất dùng làm định danh channel",
+    "displayName": "Tên hiển thị",
+    "displayNamePlaceholder": "Sales Bot",
+    "channelType": "Loại channel *",
+    "agent": "Agent *",
+    "selectAgent": "Chọn agent",
+    "credentials": "Thông tin xác thực",
+    "credentialsHint": "(để trống để giữ giá trị hiện tại)",
+    "credentialsEncrypted": "Được mã hóa phía máy chủ. Không bao giờ trả về trong phản hồi API.",
+    "configuration": "Cấu hình",
+    "enabled": "Bật",
+    "cancel": "Hủy",
+    "create": "Tạo",
+    "update": "Cập nhật",
+    "saving": "Đang lưu...",
+    "step": "Bước {{current}} / {{total}}",
+    "authenticate": "Xác thực — {{label}}",
+    "configure": "Cấu hình — {{label}}",
+    "skip": "Bỏ qua",
+    "done": "Xong",
+    "errors": {
+      "keyRequired": "Khóa là bắt buộc",
+      "keySlug": "Khóa phải là slug hợp lệ (chữ thường, số, dấu gạch ngang)",
+      "agentRequired": "Agent là bắt buộc",
+      "requiredFields": "Bắt buộc: {{fields}}",
+      "failedSave": "Không thể lưu",
+      "failedSaveConfig": "Không thể lưu cấu hình"
+    },
+    "authStatus": {
+      "authenticated": "Đã xác thực",
+      "notAuthenticated": "Chưa xác thực",
+      "useQrHint": "— Dùng nút đăng nhập QR từ bảng channel"
+    }
+  },
+  "detail": {
+    "agent": "Agent: {{name}}",
+    "tabs": {
+      "general": "Chung",
+      "config": "Cấu hình",
+      "credentials": "Thông tin xác thực",
+      "groups": "Nhóm",
+      "writers": "Người viết"
+    },
+    "general": {
+      "name": "Tên",
+      "nameHint": "Slug duy nhất (chỉ đọc)",
+      "channelType": "Loại channel",
+      "displayName": "Tên hiển thị",
+      "displayNamePlaceholder": "Tên thân thiện",
+      "agent": "Agent",
+      "selectAgent": "Chọn agent",
+      "enabled": "Bật",
+      "saved": "Đã lưu",
+      "saveChanges": "Lưu thay đổi",
+      "saving": "Đang lưu..."
+    },
+    "credentials": {
+      "hint": "Để trống các trường để giữ giá trị hiện tại. Thông tin xác thực được mã hóa phía máy chủ và không bao giờ trả về trong phản hồi API.",
+      "noSchema": "Không có lược đồ thông tin xác thực cho loại channel này.",
+      "noCredentials": "Không có thông tin xác thực để cập nhật",
+      "failedSave": "Lưu thất bại",
+      "saved": "Đã lưu",
+      "updateCredentials": "Cập nhật thông tin xác thực",
+      "saving": "Đang lưu..."
+    },
+    "config": {
+      "noSchema": "Không có lược đồ cấu hình cho loại channel này.",
+      "saved": "Đã lưu",
+      "saveConfig": "Lưu cấu hình",
+      "saving": "Đang lưu..."
+    },
+    "groups": {
+      "saved": "Đã lưu",
+      "saveGroups": "Lưu nhóm",
+      "saving": "Đang lưu..."
+    },
+    "writers": {
+      "description": "Quản lý người dùng được phép viết/chỉnh sửa tệp trong cuộc trò chuyện nhóm.",
+      "groups": "Nhóm",
+      "noWriterGroups": "Không có nhóm người viết",
+      "noWriterGroupsHint": "Dùng biểu mẫu bên dưới để thêm người viết vào nhóm.",
+      "loadingWriters": "Đang tải người viết...",
+      "noWriters": "Không có người viết trong nhóm này.",
+      "writersCount": "{{count}} người viết",
+      "writersCountPlural": "{{count}} người viết",
+      "columns": {
+        "userId": "ID người dùng",
+        "name": "Tên",
+        "username": "Tên đăng nhập"
+      },
+      "addForm": {
+        "title": "Thêm người viết vào nhóm mới",
+        "hint": "Thêm người viết vào nhóm chưa xuất hiện trong danh sách trên.",
+        "groupId": "ID nhóm *",
+        "groupIdPlaceholder": "vd: group:telegram:-100123456",
+        "userId": "ID người dùng *",
+        "userIdPlaceholder": "vd: 12345678",
+        "displayName": "Tên hiển thị",
+        "username": "Tên đăng nhập",
+        "optional": "Tùy chọn",
+        "usernameWithout": "Tùy chọn (không có @)",
+        "adding": "Đang thêm...",
+        "addWriter": "Thêm người viết",
+        "add": "Thêm",
+        "errors": {
+          "groupUserRequired": "ID nhóm và ID người dùng là bắt buộc",
+          "failedAdd": "Không thể thêm người viết"
+        }
+      }
+    }
+  },
+  "groupOverrides": {
+    "title": "Ghi đè nhóm & chủ đề",
+    "hint": "Ghi đè mặc định channel theo cuộc trò chuyện nhóm hoặc chủ đề diễn đàn. Dùng \"*\" làm ID nhóm cho mặc định ký tự đại diện.",
+    "groupLabel": "Nhóm: {{id}}",
+    "groupWildcard": "* (ký tự đại diện)",
+    "addGroupPlaceholder": "ID cuộc trò chuyện (vd: -100123456) hoặc *",
+    "addGroup": "Thêm nhóm",
+    "topicOverrides": "Ghi đè chủ đề",
+    "topicLabel": "Chủ đề: {{id}}",
+    "addTopicPlaceholder": "ID luồng chủ đề",
+    "addTopic": "Thêm chủ đề",
+    "fields": {
+      "groupPolicy": "Chính sách nhóm",
+      "requireMention": "Yêu cầu @đề cập",
+      "enabled": "Bật",
+      "allowedUsers": "Người dùng được phép",
+      "allowedUsersPlaceholder": "Mỗi ID người dùng một dòng",
+      "skillsFilter": "Bộ lọc skill",
+      "skillsPlaceholder": "Mỗi tên skill một dòng (trống = kế thừa)",
+      "toolAllow": "Công cụ được phép",
+      "toolAllowPlaceholder": "Chọn công cụ được phép (trống = kế thừa tất cả)...",
+      "toolAllowHint": "Giới hạn công cụ có sẵn trong nhóm này. Hỗ trợ tên nhóm như \"group:web\", \"group:fs\". Trống = kế thừa tất cả công cụ.",
+      "systemPrompt": "Prompt hệ thống",
+      "systemPromptPlaceholder": "Prompt hệ thống bổ sung cho nhóm/chủ đề này",
+      "inherit": "Kế thừa (mặc định channel)",
+      "yes": "Có",
+      "no": "Không"
+    }
+  },
+  "toast": {
+    "created": "Đã tạo channel",
+    "createdDesc": "{{name}} đã được thêm",
+    "updated": "Đã cập nhật channel",
+    "deleted": "Đã xóa channel",
+    "failedCreate": "Không thể tạo channel",
+    "failedUpdate": "Không thể cập nhật channel",
+    "failedDelete": "Không thể xóa channel"
+  },
+  "zalo": {
+    "allowedUsers": "Người dùng được phép",
+    "loadContacts": "Tải danh bạ",
+    "loading": "Đang tải...",
+    "searchContacts": "Tìm kiếm danh bạ...",
+    "friends": "Bạn bè",
+    "groups": "Nhóm",
+    "membersCount": "{{count}} thành viên",
+    "noContacts": "Không tìm thấy danh bạ",
+    "noContactsMatch": "Không có danh bạ khớp với \"{{search}}\"",
+    "addManualPlaceholder": "Thêm ID thủ công",
+    "add": "Thêm",
+    "zaloIdsHint": "ID người dùng hoặc ID nhóm Zalo",
+    "completeQrLogin": "Hoàn tất đăng nhập QR để tải danh bạ",
+    "loginQr": "Đăng nhập bằng QR — {{name}}",
+    "loginSuccessful": "Đăng nhập thành công! Đang khởi động channel...",
+    "generatingQr": "Đang tạo mã QR...",
+    "scanHint": "Quét bằng ứng dụng Zalo của bạn (hết hạn sau ~100 giây)",
+    "loginSuccessLoading": "Đăng nhập thành công! Đang tải danh bạ...",
+    "retry": "Thử lại",
+    "close": "Đóng",
+    "skip": "Bỏ qua"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/chat.json b/ui/web/src/i18n/locales/vi/chat.json
new file mode 100644
index 00000000..9d5ffd5c
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/chat.json
@@ -0,0 +1,20 @@
+{
+  "empty": {
+    "description": "Gửi tin nhắn để bắt đầu trò chuyện với agent.",
+    "title": "Bắt đầu cuộc trò chuyện"
+  },
+  "forwardedFrom": "Chuyển tiếp từ",
+  "media": {
+    "animation": "Hoạt ảnh",
+    "attached": "đính kèm",
+    "audio": "Âm thanh",
+    "document": "Tài liệu",
+    "image": "Hình ảnh",
+    "video": "Video",
+    "voice": "Tin nhắn thoại"
+  },
+  "newChat": "Trò chuyện mới",
+  "openSessions": "Mở phiên",
+  "readOnly": "Chỉ đọc — phiên này thuộc về người dùng khác",
+  "replyingTo": "Đang trả lời"
+}
diff --git a/ui/web/src/i18n/locales/vi/common.json b/ui/web/src/i18n/locales/vi/common.json
new file mode 100644
index 00000000..3a0807d4
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/common.json
@@ -0,0 +1,104 @@
+{
+  "actions": "Thao tác",
+  "active": "Hoạt động",
+  "add": "Thêm",
+  "agent": "Agent",
+  "all": "Tất cả",
+  "back": "Quay lại",
+  "builtinTools": "Tích hợp sẵn",
+  "cached": "đã lưu cache",
+  "cancel": "Hủy",
+  "cancelled": "Đã hủy",
+  "check": "Kiểm tra",
+  "checkAndCreate": "Kiểm tra & Tạo",
+  "checking": "Đang kiểm tra...",
+  "close": "Đóng",
+  "completed": "Hoàn thành",
+  "confirm": "Xác nhận",
+  "connected": "Đã kết nối",
+  "connecting": "Đang kết nối...",
+  "create": "Tạo mới",
+  "creating": "Đang tạo...",
+  "customTools": "Tùy chỉnh",
+  "default": "mặc định",
+  "delete": "Xóa",
+  "description": "Mô tả",
+  "disabled": "Đã tắt",
+  "disconnected": "Đã ngắt kết nối",
+  "disconnectedGateway": "Mất kết nối với gateway. Đang thử kết nối lại...",
+  "edit": "Chỉnh sửa",
+  "enabled": "Đã bật",
+  "enterOrSelectModel": "Nhập hoặc chọn model",
+  "failed": "Thất bại",
+  "filesBack": "Tệp",
+  "filter": "Lọc",
+  "format": "Định dạng JSON",
+  "global": "Toàn cục",
+  "invalidJson": "Cú pháp JSON không hợp lệ",
+  "items": "mục",
+  "live": "Trực tiếp",
+  "loading": "Đang tải...",
+  "loadingModels": "Đang tải model...",
+  "manage": "Quản lý",
+  "messages": "tin nhắn",
+  "model": "Model",
+  "modelTip": "ID model để sử dụng.",
+  "modelVerified": "Model đã được xác minh",
+  "name": "Tên",
+  "no": "Không",
+  "noAgentsAvailable": "Không có agent nào",
+  "noDescription": "Không có mô tả",
+  "noFiles": "Không tìm thấy tệp nào.",
+  "noProvidersConfigured": "Chưa cấu hình provider",
+  "noSessions": "Chưa có phiên nào. Bắt đầu chat!",
+  "none": "Không có",
+  "notSet": "Chưa thiết lập",
+  "optional": "Tùy chọn",
+  "pageOf": "Trang {{page}} / {{totalPages}}",
+  "pending": "Đang chờ",
+  "provider": "Provider",
+  "providerTip": "Tên provider LLM. Phải khớp với một provider đã cấu hình.",
+  "refresh": "Làm mới",
+  "required": "Bắt buộc",
+  "retry": "Thử lại",
+  "rows": "Hàng",
+  "running": "Đang chạy",
+  "save": "Lưu",
+  "saveChanges": "Lưu thay đổi",
+  "saveConfig": "Lưu cấu hình",
+  "saved": "Đã lưu",
+  "saving": "Đang lưu...",
+  "search": "Tìm kiếm...",
+  "searchPlaceholder": "Tìm kiếm...",
+  "selectAgent": "Chọn agent",
+  "selectFileToView": "Chọn một tệp để xem nội dung",
+  "selectOrTypeTools": "Chọn hoặc nhập tên công cụ...",
+  "selectProvider": "Chọn provider",
+  "sendMessage": "Gửi tin nhắn... (Shift+Enter để xuống dòng)",
+  "sendMessageTitle": "Gửi tin nhắn",
+  "skillActivated": "Đã kích hoạt",
+  "skillActivating": "Đang kích hoạt...",
+  "status": "Trạng thái",
+  "stopGeneration": "Dừng tạo",
+  "stopped": "Đã dừng",
+  "thinking": "Đang suy nghĩ",
+  "thinkingStreaming": "Đang suy nghĩ...",
+  "toolArguments": "Tham số",
+  "toolDone": "Hoàn thành",
+  "toolFailed": "Thất bại",
+  "toolResult": "Kết quả",
+  "toolRunning": "Đang chạy...",
+  "tryDifferentSearch": "Thử từ khóa tìm kiếm khác.",
+  "type": "Loại",
+  "typeAndPressEnter": "Nhập và nhấn Enter...",
+  "typeToConfirmPrefix": "Nhập",
+  "typeToConfirmSuffix": "để xác nhận.",
+  "unknown": "Không xác định",
+  "unsavedChanges": "Có thay đổi chưa lưu",
+  "update": "Cập nhật",
+  "upload": "Tải lên",
+  "usingGlobalDefaults": "Đang dùng giá trị mặc định toàn cục từ config.json",
+  "verificationFailed": "Xác minh thất bại",
+  "view": "Xem",
+  "yes": "Có"
+}
diff --git a/ui/web/src/i18n/locales/vi/cron.json b/ui/web/src/i18n/locales/vi/cron.json
new file mode 100644
index 00000000..7f4b7ccd
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/cron.json
@@ -0,0 +1,102 @@
+{
+  "title": "Tác vụ định kỳ",
+  "description": "Lên lịch các tác vụ agent định kỳ",
+  "newJob": "Tác vụ mới",
+  "emptyTitle": "Không có tác vụ định kỳ",
+  "emptyDescription": "Tạo tác vụ định kỳ để lên lịch các tác vụ agent định kỳ.",
+  "columns": {
+    "enabled": "Bật",
+    "name": "Tên",
+    "schedule": "Lịch",
+    "message": "Tin nhắn",
+    "agent": "Agent",
+    "actions": "Thao tác"
+  },
+  "runNow": "Chạy ngay",
+  "running": "Đang chạy...",
+  "runHistory": "Lịch sử chạy",
+  "defaultAgent": "mặc định",
+  "create": {
+    "title": "Tạo tác vụ định kỳ",
+    "name": "Tên",
+    "namePlaceholder": "my-daily-task",
+    "nameHint": "Chỉ chữ thường, số và dấu gạch ngang",
+    "agentId": "Agent ID (tùy chọn)",
+    "agentIdPlaceholder": "mặc định",
+    "scheduleType": "Loại lịch",
+    "every": "Mỗi",
+    "cron": "Cron",
+    "once": "Một lần",
+    "intervalSeconds": "Khoảng thời gian (giây)",
+    "cronExpression": "Biểu thức Cron",
+    "cronHint": "Cron 5 trường tiêu chuẩn: phút giờ ngày tháng thứ",
+    "onceDesc": "Tác vụ sẽ chạy một lần, khoảng 1 phút kể từ bây giờ.",
+    "message": "Tin nhắn",
+    "messagePlaceholder": "Agent cần làm gì?",
+    "cancel": "Hủy",
+    "create": "Tạo",
+    "creating": "Đang tạo..."
+  },
+  "enable": {
+    "title": "Bật tác vụ định kỳ",
+    "description": "Bật \"{{name}}\"? Tác vụ sẽ bắt đầu chạy theo lịch.",
+    "confirmLabel": "Bật"
+  },
+  "disable": {
+    "title": "Tắt tác vụ định kỳ",
+    "description": "Tắt \"{{name}}\"? Tác vụ sẽ dừng chạy cho đến khi được bật lại.",
+    "confirmLabel": "Tắt"
+  },
+  "delete": {
+    "title": "Xóa tác vụ định kỳ",
+    "description": "Xóa \"{{name}}\"? Hành động này không thể hoàn tác.",
+    "confirmLabel": "Xóa"
+  },
+  "runLog": {
+    "title": "Lịch sử chạy: {{name}}",
+    "noHistory": "Chưa có lịch sử chạy nào.",
+    "loading": "Đang tải..."
+  },
+  "detail": {
+    "runNow": "Chạy ngay",
+    "running": "Đang chạy...",
+    "disable": "Tắt",
+    "enable": "Bật",
+    "delete": "Xóa",
+    "enabled": "đã bật",
+    "disabled": "đã tắt",
+    "runningStatus": "đang chạy...",
+    "payload": "Tải trọng",
+    "empty": "(trống)",
+    "deliverDirect": "Gửi: trực tiếp",
+    "channel": "Channel: {{name}}",
+    "to": "Đến: {{name}}",
+    "lastError": "Lỗi gần nhất",
+    "runHistory": "Lịch sử chạy",
+    "refresh": "Làm mới",
+    "noHistory": "Chưa có lịch sử chạy nào.",
+    "inOut": "{{input}} vào / {{output}} ra",
+    "infoRows": {
+      "schedule": "Lịch",
+      "timezone": "Múi giờ",
+      "nextRun": "Lần chạy tiếp theo",
+      "lastRun": "Lần chạy gần nhất",
+      "created": "Đã tạo",
+      "updated": "Đã cập nhật",
+      "autoDelete": "Tự động xóa",
+      "autoDeleteValue": "Có (một lần)"
+    }
+  },
+  "toast": {
+    "created": "Đã tạo tác vụ định kỳ",
+    "createdDesc": "{{name}} đã được thêm",
+    "enabled": "Đã bật tác vụ định kỳ",
+    "disabled": "Đã tắt tác vụ định kỳ",
+    "deleted": "Đã xóa tác vụ định kỳ",
+    "triggered": "Đã kích hoạt tác vụ định kỳ",
+    "failedCreate": "Không thể tạo tác vụ định kỳ",
+    "failedToggle": "Không thể chuyển đổi tác vụ định kỳ",
+    "failedDelete": "Không thể xóa tác vụ định kỳ",
+    "failedRun": "Không thể chạy tác vụ định kỳ"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/delegations.json b/ui/web/src/i18n/locales/vi/delegations.json
new file mode 100644
index 00000000..79fc54fd
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/delegations.json
@@ -0,0 +1,41 @@
+{
+  "title": "Ủy quyền",
+  "description": "Lịch sử và kết quả ủy quyền agent",
+  "sourceFilterPlaceholder": "Agent nguồn...",
+  "targetFilterPlaceholder": "Agent đích...",
+  "filter": "Lọc",
+  "emptyTitle": "Không có ủy quyền",
+  "emptyDescription": "Không tìm thấy bản ghi ủy quyền. Ủy quyền được ghi lại khi agent ủy thác nhiệm vụ cho agent khác.",
+  "columns": {
+    "sourceTarget": "Nguồn / Đích",
+    "task": "Nhiệm vụ",
+    "status": "Trạng thái",
+    "mode": "Chế độ",
+    "duration": "Thời lượng",
+    "time": "Thời gian"
+  },
+  "statusFilter": {
+    "all": "Tất cả",
+    "pending": "Đang chờ",
+    "running": "Đang chạy",
+    "completed": "Hoàn thành",
+    "failed": "Thất bại",
+    "cancelled": "Đã hủy"
+  },
+  "detail": {
+    "title": "Chi tiết ủy quyền",
+    "notFound": "Không tìm thấy ủy quyền.",
+    "source": "Nguồn:",
+    "target": "Đích:",
+    "status": "Trạng thái:",
+    "mode": "Chế độ:",
+    "duration": "Thời lượng:",
+    "iterations": "Số lần lặp:",
+    "created": "Đã tạo:",
+    "completed": "Hoàn thành:",
+    "trace": "Theo dõi:",
+    "task": "Nhiệm vụ",
+    "result": "Kết quả",
+    "error": "Lỗi"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/events.json b/ui/web/src/i18n/locales/vi/events.json
new file mode 100644
index 00000000..1a8f59bd
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/events.json
@@ -0,0 +1,34 @@
+{
+  "title": "Sự kiện thời gian thực",
+  "description": "Sự kiện WebSocket trực tiếp trên tất cả nhóm và agent",
+  "live": "Trực tiếp",
+  "paused": "Tạm dừng",
+  "resume": "Tiếp tục",
+  "pause": "Tạm dừng",
+  "clear": "Xóa",
+  "scrollToBottom": "Cuộn xuống dưới",
+  "eventCount": "{{count}} sự kiện",
+  "eventCountPlural": "{{count}} sự kiện",
+  "categories": {
+    "all": "Tất cả",
+    "delegation": "Ủy quyền",
+    "task": "Nhiệm vụ",
+    "message": "Tin nhắn",
+    "agent": "Agent",
+    "teamCrud": "CRUD Nhóm",
+    "agentLink": "Liên kết agent"
+  },
+  "filters": {
+    "allTeams": "Tất cả nhóm",
+    "allUsers": "Tất cả người dùng",
+    "allChats": "Tất cả cuộc trò chuyện"
+  },
+  "global": "Toàn cục",
+  "emptyTitle": "Chưa có sự kiện nào",
+  "emptyPaused": "Chụp sự kiện đang tạm dừng. Tiếp tục để xem sự kiện mới.",
+  "emptyWaiting": "Đang chờ sự kiện thời gian thực... Sự kiện sẽ xuất hiện khi agent hoạt động.",
+  "detail": {
+    "copy": "Sao chép",
+    "copied": "Đã sao chép"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/login.json b/ui/web/src/i18n/locales/vi/login.json
new file mode 100644
index 00000000..61ef7ca7
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/login.json
@@ -0,0 +1,32 @@
+{
+  "pairing": {
+    "approved": "Truy cập đã được phê duyệt! Đang chuyển hướng...",
+    "askAdmin": "Yêu cầu quản trị viên phê duyệt mã này:",
+    "cancel": "Hủy",
+    "connecting": "Đang kết nối...",
+    "errorCannotConnect": "Không thể kết nối đến gateway.",
+    "errorConnectionLost": "Mất kết nối. Vui lòng thử lại.",
+    "noTokenNeeded": "Không cần token. Mã ghép nối sẽ được tạo để quản trị viên phê duyệt.",
+    "orRun": "Hoặc chạy:",
+    "requestAccess": "Yêu cầu truy cập",
+    "userId": "User ID",
+    "userIdPlaceholder": "your-user-id",
+    "waitingForApproval": "Đang chờ phê duyệt..."
+  },
+  "subtitle": "Đăng nhập vào bảng điều khiển gateway",
+  "tabs": {
+    "pairing": "Ghép nối",
+    "token": "Token"
+  },
+  "token": {
+    "connect": "Kết nối",
+    "connecting": "Đang kết nối...",
+    "errorCannotConnect": "Không thể kết nối đến gateway. Kiểm tra server đã chạy chưa.",
+    "errorInvalidCredentials": "Thông tin xác thực không hợp lệ. Kiểm tra token và user ID.",
+    "errorServer": "Server trả về {{status}}. Vui lòng thử lại.",
+    "gatewayToken": "Gateway Token",
+    "tokenPlaceholder": "Bearer token",
+    "userId": "User ID",
+    "userIdPlaceholder": "your-user-id"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/logs.json b/ui/web/src/i18n/locales/vi/logs.json
new file mode 100644
index 00000000..e614d4fc
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/logs.json
@@ -0,0 +1,15 @@
+{
+  "title": "Nhật ký",
+  "description": "Xem nhật ký trực tiếp",
+  "descriptionLive": "Đang xem trực tiếp ở mức {{level}}",
+  "live": "Trực tiếp",
+  "start": "Bắt đầu",
+  "stop": "Dừng",
+  "clear": "Xóa",
+  "filterPlaceholder": "Lọc nhật ký...",
+  "logLevelTitle": "Mức nhật ký",
+  "emptyWaiting": "Đang chờ nhật ký...",
+  "emptyFilter": "Không có nhật ký nào khớp bộ lọc.",
+  "emptyStart": "Nhấn \"Bắt đầu\" để xem nhật ký trực tiếp.",
+  "count": "{{filtered}}/{{total}}"
+}
diff --git a/ui/web/src/i18n/locales/vi/mcp.json b/ui/web/src/i18n/locales/vi/mcp.json
new file mode 100644
index 00000000..a547d916
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/mcp.json
@@ -0,0 +1,99 @@
+{
+  "title": "MCP Servers",
+  "description": "Quản lý kết nối máy chủ Model Context Protocol",
+  "addServer": "Thêm máy chủ",
+  "searchPlaceholder": "Tìm kiếm máy chủ...",
+  "emptyTitle": "Không có MCP server",
+  "emptyDescription": "Thêm MCP server đầu tiên để bắt đầu.",
+  "noMatchTitle": "Không tìm thấy máy chủ phù hợp",
+  "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+  "columns": {
+    "name": "Tên",
+    "transport": "Giao thức",
+    "tools": "Công cụ",
+    "enabled": "Bật",
+    "createdBy": "Tạo bởi",
+    "actions": "Thao tác"
+  },
+  "viewTools": "Xem công cụ",
+  "manageGrants": "Quản lý quyền",
+  "delete": {
+    "title": "Xóa MCP Server",
+    "description": "Bạn có chắc muốn xóa \"{{name}}\"? Tất cả quyền liên quan cũng sẽ bị xóa.",
+    "confirmLabel": "Xóa"
+  },
+  "form": {
+    "createTitle": "Thêm MCP Server",
+    "editTitle": "Chỉnh sửa MCP Server",
+    "name": "Tên *",
+    "nameHint": "Chỉ dùng chữ thường, số và dấu gạch ngang",
+    "displayName": "Tên hiển thị",
+    "transport": "Giao thức *",
+    "command": "Lệnh *",
+    "args": "Tham số (phân cách bằng dấu phẩy)",
+    "argsPlaceholder": "--flag1, --flag2",
+    "url": "URL *",
+    "headers": "Headers",
+    "headerKeyPlaceholder": "Tên header",
+    "headerValuePlaceholder": "Giá trị header",
+    "addHeader": "Thêm Header",
+    "env": "Biến môi trường",
+    "envKeyPlaceholder": "Tên biến",
+    "envValuePlaceholder": "Giá trị",
+    "addVariable": "Thêm biến",
+    "toolPrefix": "Tiền tố công cụ",
+    "toolPrefixHint": "Tự động lấy từ tên nếu để trống.",
+    "timeout": "Thời gian chờ (giây)",
+    "enabled": "Bật",
+    "testConnection": "Kiểm tra kết nối",
+    "testing": "Đang kiểm tra...",
+    "toolsFound": "Tìm thấy {{count}} công cụ",
+    "cancel": "Hủy",
+    "create": "Tạo",
+    "update": "Cập nhật",
+    "saving": "Đang lưu...",
+    "errors": {
+      "nameRequired": "Tên và giao thức là bắt buộc",
+      "nameSlug": "Tên phải là slug hợp lệ (chữ thường, số, dấu gạch ngang)",
+      "commandRequired": "Lệnh là bắt buộc cho giao thức stdio",
+      "urlRequired": "URL là bắt buộc cho giao thức SSE/HTTP",
+      "connectionFailed": "Kết nối thất bại"
+    }
+  },
+  "grants": {
+    "title": "Quyền agent - {{name}}",
+    "currentGrants": "Quyền hiện tại",
+    "allToolsAllowed": "Tất cả công cụ được phép",
+    "addGrant": "Thêm quyền agent",
+    "editGrant": "Chỉnh sửa quyền",
+    "selectAgent": "Chọn agent...",
+    "toolAllowList": "Danh sách công cụ được phép (tùy chọn)",
+    "toolDenyList": "Danh sách công cụ bị từ chối (tùy chọn)",
+    "allowPlaceholder": "Chọn công cụ để cho phép...",
+    "denyPlaceholder": "Chọn công cụ để từ chối...",
+    "grant": "Cấp quyền",
+    "update": "Cập nhật",
+    "cancel": "Hủy",
+    "agentRequired": "Agent là bắt buộc",
+    "failedGrant": "Cấp quyền thất bại",
+    "failedRevoke": "Thu hồi quyền thất bại"
+  },
+  "tools": {
+    "title": "Công cụ — {{name}}",
+    "prefix": "tiền tố:",
+    "discovering": "Đang khám phá công cụ...",
+    "noToolsTitle": "Không tìm thấy công cụ",
+    "noToolsDescription": "Máy chủ có thể ngoại tuyến hoặc không có công cụ nào được đăng ký.",
+    "failedLoad": "Không thể tải công cụ",
+    "filterPlaceholder": "Lọc công cụ...",
+    "noMatch": "Không có công cụ phù hợp"
+  },
+  "toast": {
+    "created": "Đã tạo MCP server",
+    "updated": "Đã cập nhật MCP server",
+    "deleted": "Đã xóa MCP server",
+    "failedCreate": "Không thể tạo MCP server",
+    "failedUpdate": "Không thể cập nhật MCP server",
+    "failedDelete": "Không thể xóa MCP server"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/memory.json b/ui/web/src/i18n/locales/vi/memory.json
new file mode 100644
index 00000000..6fae75b5
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/memory.json
@@ -0,0 +1,166 @@
+{
+  "title": "Bộ nhớ",
+  "description": "Duyệt và quản lý tài liệu bộ nhớ, đoạn trích và nhúng của agent",
+  "search": "Tìm kiếm",
+  "create": "Tạo",
+  "indexAll": "Lập chỉ mục tất cả",
+  "indexing": "Đang lập chỉ mục...",
+  "emptyTitle": "Không có tài liệu bộ nhớ",
+  "emptyAgentDescription": "Agent này chưa có tài liệu bộ nhớ.",
+  "emptyGlobalDescription": "Không tìm thấy tài liệu bộ nhớ trên bất kỳ agent nào.",
+  "filters": {
+    "agent": "Agent",
+    "allAgents": "Tất cả agent",
+    "scope": "Phạm vi",
+    "allScope": "Tất cả (toàn cục + cá nhân)"
+  },
+  "tabs": {
+    "documents": "Tài liệu",
+    "knowledgeGraph": "Đồ thị tri thức"
+  },
+  "columns": {
+    "path": "Đường dẫn",
+    "agent": "Agent",
+    "scope": "Phạm vi",
+    "hash": "Mã băm",
+    "updated": "Cập nhật",
+    "actions": "Thao tác"
+  },
+  "scopeLabel": {
+    "personal": "Cá nhân",
+    "global": "Toàn cục"
+  },
+  "delete": {
+    "title": "Xóa tài liệu bộ nhớ",
+    "description": "Bạn có chắc muốn xóa \"{{path}}\"? Tất cả đoạn trích và nhúng liên quan cũng sẽ bị xóa.",
+    "confirmLabel": "Xóa"
+  },
+  "createDialog": {
+    "title": "Tạo tài liệu bộ nhớ",
+    "path": "Đường dẫn *",
+    "pathPlaceholder": "vd. notes/project-overview.md",
+    "content": "Nội dung *",
+    "contentPlaceholder": "Nội dung tài liệu...",
+    "agentId": "Agent *",
+    "agentIdPlaceholder": "Chọn agent...",
+    "scope": "Phạm vi",
+    "existingScope": "Phạm vi hiện có",
+    "customScope": "Tùy chỉnh",
+    "selectGroupUser": "Chọn nhóm/người dùng...",
+    "scopeHint": "Toàn cục = chia sẻ với mọi người dùng. Cá nhân = giới hạn cho người dùng hoặc chat nhóm cụ thể.",
+    "autoIndex": "Tự động lập chỉ mục sau khi tạo",
+    "agentRequired": "Vui lòng chọn agent",
+    "pathRequired": "Đường dẫn là bắt buộc",
+    "contentRequired": "Nội dung là bắt buộc",
+    "cancel": "Hủy",
+    "create": "Tạo",
+    "creating": "Đang tạo..."
+  },
+  "documentDialog": {
+    "title": "Tài liệu bộ nhớ",
+    "path": "Đường dẫn:",
+    "agent": "Agent:",
+    "scope": "Phạm vi:",
+    "hash": "Mã băm:",
+    "updated": "Cập nhật:",
+    "content": "Nội dung",
+    "chunks": "Đoạn trích ({{count}})",
+    "chunkIndex": "Đoạn {{index}}",
+    "noChunks": "Không có đoạn trích",
+    "embedded": "Đã nhúng",
+    "noEmbedding": "Chưa nhúng"
+  },
+  "searchDialog": {
+    "title": "Tìm kiếm bộ nhớ",
+    "query": "Truy vấn tìm kiếm",
+    "queryPlaceholder": "Nhập truy vấn tìm kiếm...",
+    "agentId": "Agent ID",
+    "agentIdPlaceholder": "Lọc theo agent...",
+    "limit": "Giới hạn",
+    "search": "Tìm kiếm",
+    "searching": "Đang tìm kiếm...",
+    "results": "Kết quả",
+    "noResults": "Không tìm thấy kết quả",
+    "similarity": "tương đồng",
+    "path": "Đường dẫn:"
+  },
+  "kg": {
+    "emptyTitle": "Không có thực thể",
+    "emptyDescription": "Chưa có thực thể đồ thị tri thức nào cho agent này.",
+    "emptySearchDescription": "Không có thực thể nào khớp với tìm kiếm của bạn.",
+    "stats": {
+      "entities": "Thực thể: {{count}}",
+      "relations": "Quan hệ: {{count}}"
+    },
+    "search": {
+      "placeholder": "Tìm kiếm thực thể...",
+      "button": "Tìm kiếm",
+      "clear": "Xóa"
+    },
+    "refresh": "Làm mới",
+    "extract": "Trích xuất",
+    "columns": {
+      "name": "Tên",
+      "type": "Loại",
+      "description": "Mô tả",
+      "confidence": "Độ tin cậy",
+      "actions": "Thao tác",
+      "observations": "Quan sát",
+      "relations": "Quan hệ"
+    },
+    "deleteEntity": {
+      "title": "Xóa thực thể",
+      "description": "Xóa \"{{name}}\"? Tất cả quan hệ liên quan cũng sẽ bị xóa.",
+      "confirmLabel": "Xóa"
+    },
+    "entity": {
+      "externalId": "ID ngoài:",
+      "confidence": "Độ tin cậy:",
+      "description": "Mô tả:",
+      "source": "Nguồn:",
+      "properties": "Thuộc tính:",
+      "relations": "Quan hệ",
+      "traverse": "Duyệt (2 bước)",
+      "traversing": "Đang duyệt...",
+      "loading": "Đang tải...",
+      "noRelations": "Không tìm thấy quan hệ.",
+      "traversalResults": "Kết quả duyệt ({{count}})",
+      "direction": {
+        "outgoing": "→ đi ra",
+        "incoming": "← đi vào"
+      },
+      "columns": {
+        "direction": "Chiều",
+        "relation": "Quan hệ",
+        "target": "Đích",
+        "confidence": "Độ tin cậy"
+      }
+    },
+    "extractDialog": {
+      "title": "Trích xuất thực thể từ văn bản",
+      "providerLabel": "Provider trích xuất",
+      "modelLabel": "Mô hình trích xuất",
+      "textLabel": "Văn bản để trích xuất",
+      "textPlaceholder": "Dán nội dung hội thoại, ghi chú hoặc bất kỳ văn bản nào để trích xuất thực thể và quan hệ...",
+      "extract": "Trích xuất",
+      "extracting": "Đang trích xuất...",
+      "cancel": "Hủy",
+      "agentId": "Agent ID",
+      "agentIdPlaceholder": "Để trống cho toàn cục"
+    },
+    "graphView": {
+      "loading": "Đang tải đồ thị...",
+      "empty": "Không có thực thể nào để hiển thị",
+      "nodes": "{{count}} nút",
+      "edges": "{{count}} cạnh"
+    }
+  },
+  "toast": {
+    "created": "Đã tạo tài liệu bộ nhớ",
+    "deleted": "Đã xóa tài liệu bộ nhớ",
+    "indexed": "Đã lập chỉ mục tất cả tài liệu",
+    "failedCreate": "Không thể tạo tài liệu",
+    "failedDelete": "Không thể xóa tài liệu",
+    "failedIndex": "Không thể lập chỉ mục tài liệu"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/nodes.json b/ui/web/src/i18n/locales/vi/nodes.json
new file mode 100644
index 00000000..45f00f3c
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/nodes.json
@@ -0,0 +1,35 @@
+{
+  "title": "Nút",
+  "description": "Quản lý thiết bị ghép nối và yêu cầu ghép nối đang chờ",
+  "emptyTitle": "Không có thiết bị nào",
+  "emptyDescription": "Không có thiết bị ghép nối hoặc yêu cầu ghép nối đang chờ.",
+  "pendingRequests": "Yêu cầu đang chờ ({{count}})",
+  "pairedDevices": "Thiết bị đã ghép nối ({{count}})",
+  "sender": "Người gửi: ",
+  "chat": "Cuộc trò chuyện: ",
+  "columns": {
+    "channel": "Channel",
+    "senderId": "Sender ID",
+    "paired": "Đã ghép nối",
+    "by": "Bởi",
+    "actions": "Thao tác"
+  },
+  "approve": "Phê duyệt",
+  "deny": "Từ chối",
+  "revoke": "Thu hồi",
+  "confirmApprove": {
+    "title": "Phê duyệt ghép nối",
+    "description": "Phê duyệt yêu cầu ghép nối từ {{channel}}:{{senderId}} (mã: {{code}})? Thiết bị này sẽ có thể tương tác với các agent.",
+    "confirmLabel": "Phê duyệt"
+  },
+  "confirmDeny": {
+    "title": "Từ chối ghép nối",
+    "description": "Từ chối yêu cầu ghép nối từ {{channel}}:{{senderId}} (mã: {{code}})? Yêu cầu sẽ bị xóa.",
+    "confirmLabel": "Từ chối"
+  },
+  "confirmRevoke": {
+    "title": "Thu hồi thiết bị",
+    "description": "Thu hồi ghép nối cho {{channel}}:{{senderId}}? Thiết bị sẽ cần ghép nối lại.",
+    "confirmLabel": "Thu hồi"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/overview.json b/ui/web/src/i18n/locales/vi/overview.json
new file mode 100644
index 00000000..3dcf13e6
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/overview.json
@@ -0,0 +1,74 @@
+{
+  "connectedClients": {
+    "columns": {
+      "connected": "Kết nối lúc",
+      "ip": "IP",
+      "role": "Vai trò",
+      "user": "User"
+    },
+    "noClients": "Không có máy khách nào kết nối",
+    "title": "Máy khách đã kết nối",
+    "you": "bạn"
+  },
+  "cronJobs": {
+    "disabled": "đã tắt",
+    "manage": "Quản lý",
+    "noJobs": "Chưa cấu hình cron job nào",
+    "title": "Tác vụ định kỳ"
+  },
+  "description": "Tổng quan gateway và mức sử dụng quota",
+  "providers": {
+    "goToSettings": "Đến Cài đặt Provider",
+    "noEnabledDesc": "Tất cả provider đang bị tắt. Bật ít nhất một provider để sử dụng agent.",
+    "noEnabledTitle": "Chưa bật LLM provider nào",
+    "noProvidersDesc": "Bạn cần thêm ít nhất một provider LLM trước khi các agent có thể hoạt động. ",
+    "noProvidersTitle": "Chưa cấu hình LLM provider nào"
+  },
+  "quotaUsage": {
+    "columns": {
+      "day": "Ngày",
+      "hour": "Giờ",
+      "userGroup": "User / Group",
+      "week": "Tuần"
+    },
+    "noLimit": "không giới hạn",
+    "title": "Mức sử dụng Quota"
+  },
+  "recentRequests": {
+    "columns": {
+      "channel": "Channel",
+      "duration": "Thời gian",
+      "name": "Tên",
+      "status": "Trạng thái",
+      "time": "Thời điểm",
+      "tokens": "Token",
+      "user": "User"
+    },
+    "noRequests": "Chưa có yêu cầu nào",
+    "title": "Yêu cầu gần đây",
+    "viewAll": "Xem tất cả"
+  },
+  "statCards": {
+    "agents": "Agent",
+    "channels": "Channel",
+    "inOut": "Vào / Ra",
+    "online": "Trực tuyến",
+    "requestsToday": "Request hôm nay",
+    "running": "Đang chạy",
+    "tokensToday": "Token hôm nay",
+    "users": "Người dùng"
+  },
+  "systemHealth": {
+    "active": "hoạt động",
+    "channels": "Channel",
+    "clients": "Máy khách",
+    "database": "Cơ sở dữ liệu",
+    "none": "không có",
+    "providers": "Provider",
+    "sessions": "Session",
+    "title": "Tình trạng hệ thống",
+    "tools": "Công cụ",
+    "uptime": "Thời gian hoạt động"
+  },
+  "title": "Bảng điều khiển"
+}
diff --git a/ui/web/src/i18n/locales/vi/pending-messages.json b/ui/web/src/i18n/locales/vi/pending-messages.json
new file mode 100644
index 00000000..5de8af3b
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/pending-messages.json
@@ -0,0 +1,31 @@
+{
+  "title": "Tin nhắn đang chờ",
+  "description": "Tin nhắn channel đã được lưu đệm đang chờ xử lý từ agent",
+  "emptyTitle": "Không có tin nhắn đang chờ",
+  "emptyDescription": "Không tìm thấy nhóm tin nhắn đệm. Tin nhắn xuất hiện ở đây khi channel lưu đệm tin nhắn đến trước khi agent xử lý.",
+  "columns": {
+    "channel": "Channel",
+    "group": "Nhóm",
+    "messages": "Tin nhắn",
+    "status": "Trạng thái",
+    "lastActivity": "Hoạt động gần nhất",
+    "actions": "Thao tác"
+  },
+  "status": {
+    "compacted": "Đã nén",
+    "raw": "Thô"
+  },
+  "compact": "Nén",
+  "clear": "Xóa",
+  "confirmClear": {
+    "title": "Xóa tin nhắn?",
+    "description": "Thao tác này sẽ xóa vĩnh viễn tất cả tin nhắn trong {{channel}} / {{key}}. Không thể hoàn tác.",
+    "cancel": "Hủy",
+    "confirm": "Xóa"
+  },
+  "dialog": {
+    "title": "Tin nhắn — {{name}}",
+    "noMessages": "Không tìm thấy tin nhắn.",
+    "summary": "Tóm tắt"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/providers.json b/ui/web/src/i18n/locales/vi/providers.json
new file mode 100644
index 00000000..e3df961f
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/providers.json
@@ -0,0 +1,115 @@
+{
+  "title": "Provider",
+  "description": "Quản lý các provider LLM",
+  "addProvider": "Thêm provider",
+  "searchPlaceholder": "Tìm kiếm provider...",
+  "emptyTitle": "Không có provider",
+  "emptyDescription": "Thêm provider LLM đầu tiên để bắt đầu.",
+  "noMatchTitle": "Không tìm thấy provider phù hợp",
+  "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+  "columns": {
+    "name": "Tên",
+    "type": "Loại",
+    "apiBase": "API Base",
+    "apiKey": "API Key",
+    "status": "Trạng thái",
+    "actions": "Thao tác"
+  },
+  "apiKey": {
+    "oauthToken": "OAuth Token",
+    "notSet": "Chưa thiết lập"
+  },
+  "form": {
+    "createTitle": "Thêm provider",
+    "editTitle": "Chỉnh sửa provider",
+    "name": "Tên *",
+    "namePlaceholder": "vd: openrouter",
+    "nameHint": "Chữ thường, số, dấu gạch ngang",
+    "displayName": "Tên hiển thị",
+    "displayNamePlaceholder": "OpenRouter",
+    "providerType": "Loại provider *",
+    "apiKey": "API Key",
+    "apiKeyPlaceholder": "sk-...",
+    "apiKeyEditPlaceholder": "Giữ nguyên hoặc nhập khóa mới",
+    "apiKeySetHint": "API key đã được thiết lập. Xóa và nhập giá trị mới để thay đổi.",
+    "apiBase": "API Base URL",
+    "enabled": "Bật",
+    "cancel": "Hủy",
+    "close": "Đóng",
+    "create": "Tạo",
+    "save": "Lưu",
+    "update": "Cập nhật",
+    "saving": "Đang lưu...",
+    "creating": "Đang tạo...",
+    "alreadyAdded": "(đã thêm)",
+    "nameFixed": "Tên",
+    "configure": "Cấu hình kết nối provider LLM.",
+    "lowercaseHint": "Chữ thường, số, dấu gạch ngang"
+  },
+  "delete": {
+    "title": "Xóa provider",
+    "description": "Bạn có chắc chắn muốn xóa \"{{name}}\"? Hành động này không thể hoàn tác.",
+    "confirmLabel": "Xóa"
+  },
+  "types": {
+    "anthropic_native": "Anthropic",
+    "openai_compat": "OpenAI Compat",
+    "gemini_native": "Gemini",
+    "openrouter": "OpenRouter",
+    "groq": "Groq",
+    "deepseek": "DeepSeek",
+    "mistral": "Mistral",
+    "xai": "xAI",
+    "minimax_native": "MiniMax",
+    "cohere": "Cohere",
+    "perplexity": "Perplexity",
+    "chatgpt_oauth": "ChatGPT (OAuth)",
+    "yescale": "YesScale"
+  },
+  "oauth": {
+    "checkingStatus": "Đang kiểm tra trạng thái xác thực...",
+    "authSuccessful": "Xác thực thành công!",
+    "activeProvider": "Provider",
+    "closingIn": "đang hoạt động. Đóng sau {{count}} giây...",
+    "authenticated": "Đã xác thực — provider",
+    "active": "đang hoạt động",
+    "modelPrefixHint": "Dùng tiền tố model",
+    "modelPrefixExample": "trong cấu hình agent (vd: openai-codex/gpt-4o). Token tự động làm mới.",
+    "removeToken": "Xóa Token",
+    "signInDesc": "Đăng nhập bằng tài khoản ChatGPT để sử dụng các model trong gói đăng ký mà không cần API key riêng.",
+    "waiting": "Đang chờ xác thực... Hoàn tất đăng nhập trong cửa sổ đã mở.",
+    "remoteVpsHint": "Sau khi đăng nhập, trình duyệt sẽ cố mở",
+    "remoteVpsError": "và hiển thị lỗi \"Không thể truy cập trang này\". Điều này là bình thường — sao chép URL đầy đủ từ thanh địa chỉ trình duyệt và dán vào bên dưới.",
+    "pasteUrlPlaceholder": "http://localhost:1455/auth/callback?code=...&state=...",
+    "submit": "Gửi",
+    "signInWithChatGPT": "Đăng nhập với ChatGPT",
+    "starting": "Đang bắt đầu...",
+    "remoteVps": "Remote/VPS?",
+    "loggedOut": "Đã đăng xuất",
+    "loggedOutDesc": "Đã xóa OAuth token OpenAI",
+    "oauthFailed": "OAuth thất bại",
+    "exchangeFailed": "Trao đổi thất bại"
+  },
+  "cli": {
+    "description": "Claude CLI sử dụng tệp nhị phân",
+    "descriptionSuffix": "cục bộ của bạn. Không cần API key.",
+    "checkingAuth": "Đang kiểm tra xác thực...",
+    "authenticatedAs": "Đã xác thực là",
+    "switchAccount": "Chuyển tài khoản?",
+    "switchAccountInstructions": "Chạy trên terminal máy chủ:",
+    "switchAccountRecheck": "Sau đó nhấp",
+    "switchAccountRecheckSuffix": "để kiểm tra lại.",
+    "notAuthenticated": "Chưa xác thực",
+    "runOnServer": "Chạy trên terminal máy chủ:",
+    "recheckButton": "Kiểm tra lại"
+  },
+  "toast": {
+    "created": "Đã tạo provider",
+    "createdDesc": "{{name}} đã được thêm",
+    "updated": "Đã cập nhật provider",
+    "deleted": "Đã xóa provider",
+    "failedCreate": "Không thể tạo provider",
+    "failedUpdate": "Không thể cập nhật provider",
+    "failedDelete": "Không thể xóa provider"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/sessions.json b/ui/web/src/i18n/locales/vi/sessions.json
new file mode 100644
index 00000000..d265749f
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/sessions.json
@@ -0,0 +1,34 @@
+{
+  "title": "Session",
+  "description": "Duyệt các session",
+  "searchPlaceholder": "Tìm kiếm session...",
+  "emptyTitle": "Chưa có session nào",
+  "emptyDescription": "Các session sẽ xuất hiện ở đây khi bạn bắt đầu trò chuyện.",
+  "noMatchTitle": "Không tìm thấy session phù hợp",
+  "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+  "columns": {
+    "session": "Session",
+    "agent": "Agent",
+    "channel": "Channel",
+    "messages": "Tin nhắn",
+    "updated": "Cập nhật"
+  },
+  "detail": {
+    "reset": "Đặt lại",
+    "delete": "Xóa",
+    "deleteTitle": "Xóa session",
+    "deleteDescription": "Thao tác này sẽ xóa vĩnh viễn tất cả tin nhắn trong session này.",
+    "resetTitle": "Đặt lại phiên",
+    "resetDescription": "Thao tác này sẽ xóa tất cả tin nhắn nhưng giữ lại phiên.",
+    "confirmDelete": "Xóa",
+    "confirmReset": "Đặt lại",
+    "noMessages": "Không có tin nhắn trong session này",
+    "summary": "Tóm tắt",
+    "showMore": "Xem thêm",
+    "showLess": "Thu gọn",
+    "showDetails": "xem chi tiết",
+    "hide": "ẩn",
+    "systemMessage": "Tin nhắn hệ thống",
+    "messages": "tin nhắn"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/setup.json b/ui/web/src/i18n/locales/vi/setup.json
new file mode 100644
index 00000000..c59c1645
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/setup.json
@@ -0,0 +1,102 @@
+{
+  "layout": {
+    "subtitle": "Hãy cùng thiết lập gateway của bạn"
+  },
+  "steps": {
+    "provider": "Provider",
+    "model": "Model",
+    "agent": "Agent",
+    "channel": "Channel",
+    "channelOptional": "(Tùy chọn)"
+  },
+  "complete": {
+    "title": "Thiết lập hoàn tất!",
+    "ready": "Hệ thống đã sẵn sàng!",
+    "description": "Provider, agent và channel đã được cấu hình. Bạn có thể quản lý chúng bất kỳ lúc nào từ bảng điều khiển.",
+    "goToDashboard": "Đến bảng điều khiển"
+  },
+  "provider": {
+    "title": "Cấu hình provider LLM",
+    "descriptionCli": "Kết nối bằng Claude CLI cục bộ. Không cần API key.",
+    "description": "Kết nối với provider AI để cấp nguồn cho agent. Bạn cần có API key.",
+    "providerType": "Loại provider",
+    "providerTypeHint": "Dịch vụ LLM bạn muốn kết nối. Khuyến nghị dùng OpenRouter để truy cập nhiều model.",
+    "name": "Tên",
+    "nameHint": "Định danh nội bộ cho provider này. Tự động tạo từ loại provider.",
+    "apiKey": "API Key *",
+    "apiKeyHint": "Khóa bí mật của provider. Được mã hóa phía máy chủ và không bao giờ lộ ra trong phản hồi API.",
+    "apiBase": "API Base URL",
+    "apiBaseHint": "URL endpoint cho các yêu cầu API. Tự động điền theo loại provider. Chỉ ghi đè nếu dùng proxy tùy chỉnh.",
+    "creating": "Đang tạo...",
+    "create": "Tạo provider",
+    "errors": {
+      "apiKeyRequired": "API key là bắt buộc",
+      "failedCreate": "Không thể tạo provider"
+    }
+  },
+  "model": {
+    "title": "Chọn & xác minh Model",
+    "description": "Chọn model và xác minh kết nối provider hoạt động.",
+    "provider": "Provider:",
+    "model": "Model *",
+    "modelHint": "AI model cần dùng. Chọn từ danh sách hoặc nhập ID model thủ công nếu chưa có trong danh sách.",
+    "loadingModels": "Đang tải model...",
+    "selectModel": "Chọn hoặc nhập ID model",
+    "noModelsHint": "Provider này không liệt kê model — hãy nhập ID model thủ công.",
+    "verified": "Đã xác minh",
+    "verify": "Xác minh",
+    "verifying": "Đang xác minh...",
+    "continue": "Tiếp tục",
+    "modelVerified": "Model đã xác minh",
+    "modelVerifiedDesc": "{{model}} đang hoạt động đúng",
+    "verificationFailed": "Xác minh thất bại. Vui lòng kiểm tra API key và model."
+  },
+  "agent": {
+    "title": "Tạo agent đầu tiên",
+    "description": "Agent là trợ lý AI của bạn. Hãy tùy chỉnh tên và cá tính.",
+    "provider": "Provider:",
+    "model": "Model:",
+    "displayName": "Tên hiển thị",
+    "displayNameHint": "Sẽ được tự động tạo trong quá trình triệu hồi dựa trên cá tính agent.",
+    "agentKey": "Khóa agent",
+    "agentKeyHint": "Định danh duy nhất cho agent. Chỉ dùng chữ thường, số và dấu gạch ngang.",
+    "agentKeyPlaceholder": "my-agent",
+    "personality": "Cá tính agent",
+    "personalityHint": "Mô tả vai trò và hành vi của agent. AI sẽ tạo các tệp ngữ cảnh từ đây trong quá trình triệu hồi.",
+    "personalityPlaceholder": "Mô tả cá tính, mục đích và hành vi của agent...",
+    "personalityHintBottom": "Tùy chỉnh prompt này để định hình cá tính và chuyên môn của agent.",
+    "selfEvolve": "Tự tiến hóa",
+    "selfEvolveDesc": "Cho phép agent tự phát triển phong cách giao tiếp theo thời gian qua SOUL.md",
+    "creating": "Đang tạo...",
+    "create": "Tạo agent",
+    "summoningFailed": "Triệu hồi thất bại. Vui lòng điều chỉnh cài đặt và thử lại.",
+    "errors": {
+      "noProvider": "Không có provider nào",
+      "failedCreate": "Không thể tạo agent"
+    }
+  },
+  "channel": {
+    "title": "Kết nối channel",
+    "description": "Kết nối nền tảng nhắn tin với agent. Bạn có thể thêm channel sau.",
+    "skip": "Bỏ qua",
+    "skipFinish": "Bỏ qua & Hoàn thành",
+    "agent": "Agent:",
+    "channelType": "Loại channel",
+    "channelTypeHint": "Nền tảng nhắn tin cần kết nối. Ví dụ: Telegram, Discord, Zalo.",
+    "name": "Tên",
+    "nameHint": "Định danh nội bộ cho channel này. Tự động tạo từ loại channel.",
+    "namePlaceholder": "my-telegram",
+    "displayName": "Tên hiển thị",
+    "displayNameHint": "Tên thân thiện hiển thị trên giao diện. Tùy chọn.",
+    "displayNamePlaceholder": "Sales Bot",
+    "credentials": "Thông tin xác thực",
+    "credentialsHint": "Được mã hóa phía máy chủ. Không bao giờ trả về trong phản hồi API.",
+    "creating": "Đang tạo...",
+    "create": "Tạo channel",
+    "errors": {
+      "noAgent": "Không có agent nào",
+      "requiredFields": "Bắt buộc: {{fields}}",
+      "failedCreate": "Không thể tạo channel"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/sidebar.json b/ui/web/src/i18n/locales/vi/sidebar.json
new file mode 100644
index 00000000..987da203
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/sidebar.json
@@ -0,0 +1,34 @@
+{
+  "groups": {
+    "core": "Chính",
+    "management": "Quản lý",
+    "monitoring": "Giám sát",
+    "system": "Hệ thống"
+  },
+  "nav": {
+    "overview": "Tổng quan",
+    "chat": "Trò chuyện",
+    "agents": "Agent",
+    "agentTeams": "Agent Team",
+    "sessions": "Session",
+    "pendingMessages": "Tin nhắn chờ",
+    "channels": "Channel",
+    "skills": "Skill",
+    "cron": "Tác vụ định kỳ",
+    "customTools": "Công cụ tùy chỉnh",
+    "builtinTools": "Công cụ tích hợp",
+    "mcpServers": "Máy chủ MCP",
+    "memory": "Bộ nhớ",
+    "traces": "Theo dõi",
+    "realtimeEvents": "Sự kiện thời gian thực",
+    "delegations": "Ủy quyền",
+    "usage": "Sử dụng",
+    "logs": "Nhật ký",
+    "storage": "Lưu trữ",
+    "providers": "Provider",
+    "config": "Cấu hình",
+    "approvals": "Phê duyệt",
+    "nodes": "Nút",
+    "tts": "Chuyển văn bản thành giọng nói"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/skills.json b/ui/web/src/i18n/locales/vi/skills.json
new file mode 100644
index 00000000..dd8c06be
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/skills.json
@@ -0,0 +1,55 @@
+{
+  "title": "Skill",
+  "description": "Quản lý skill và khả năng của agent",
+  "searchPlaceholder": "Tìm kiếm skill...",
+  "emptyTitle": "Chưa có skill",
+  "emptyDescription": "Chưa có skill nào được đăng ký.",
+  "noMatchTitle": "Không tìm thấy skill phù hợp",
+  "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+  "columns": {
+    "name": "Tên",
+    "description": "Mô tả",
+    "source": "Nguồn",
+    "visibility": "Hiển thị",
+    "actions": "Thao tác"
+  },
+  "noDescription": "Không có mô tả",
+  "delete": {
+    "title": "Xóa skill",
+    "description": "Bạn có chắc chắn muốn xóa \"{{name}}\"? Hành động này không thể hoàn tác.",
+    "confirmLabel": "Xóa"
+  },
+  "upload": {
+    "title": "Tải lên skill",
+    "description": "Tải lên tệp ZIP chứa SKILL.md ở thư mục gốc với YAML frontmatter (name, description, slug).",
+    "button": "Tải lên",
+    "uploading": "Đang tải lên...",
+    "dropOrClick": "Nhấp hoặc kéo thả tệp .zip",
+    "dropHere": "Thả tệp .zip vào đây",
+    "onlyZip": "Chỉ chấp nhận tệp .zip",
+    "cancel": "Hủy"
+  },
+  "edit": {
+    "title": "Chỉnh sửa skill",
+    "name": "Tên",
+    "description": "Mô tả",
+    "visibility": "Hiển thị",
+    "tags": "Thẻ",
+    "addTag": "Thêm thẻ...",
+    "add": "Thêm",
+    "cancel": "Hủy",
+    "save": "Lưu",
+    "saving": "Đang lưu...",
+    "privateOption": "Riêng tư (chỉ chủ sở hữu)",
+    "internalOption": "Nội bộ (agent/người dùng được cấp quyền)",
+    "publicOption": "Công khai (tất cả agent)"
+  },
+  "detail": {
+    "title": "Chi tiết skill",
+    "content": "Nội dung",
+    "files": "Tệp",
+    "version": "Phiên bản:",
+    "current": "(hiện tại)",
+    "noContent": "Không có nội dung."
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/storage.json b/ui/web/src/i18n/locales/vi/storage.json
new file mode 100644
index 00000000..7d8f2f51
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/storage.json
@@ -0,0 +1,14 @@
+{
+  "title": "Lưu trữ",
+  "description": "Trình duyệt tệp workspace",
+  "descriptionWithPath": "{{path}} — {{size}}",
+  "delete": {
+    "fileTitle": "Xóa tệp",
+    "folderTitle": "Xóa thư mục",
+    "description": "Bạn có chắc muốn xóa {{name}}?",
+    "folderWarning": " Tất cả nội dung sẽ bị xóa đệ quy.",
+    "undone": " Hành động này không thể hoàn tác.",
+    "deleting": "Đang xóa...",
+    "confirmLabel": "Xóa"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/teams.json b/ui/web/src/i18n/locales/vi/teams.json
new file mode 100644
index 00000000..8fb720be
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/teams.json
@@ -0,0 +1,150 @@
+{
+  "title": "Agent Team",
+  "description": "Quản lý các agent team của bạn",
+  "createTeam": "Tạo Team",
+  "searchPlaceholder": "Tìm kiếm Team...",
+  "emptyTitle": "Chưa có Team nào",
+  "emptyDescription": "Tạo Team đầu tiên để bắt đầu.",
+  "noMatchTitle": "Không tìm thấy Team phù hợp",
+  "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+  "delete": {
+    "title": "Xóa Team",
+    "description": "Bạn có chắc chắn muốn xóa \"{{name}}\"? Hành động này không thể hoàn tác.",
+    "confirmLabel": "Xóa"
+  },
+  "detail": {
+    "lead": "Trưởng nhóm",
+    "memberCount": "{{count}} thành viên",
+    "memberCountPlural": "{{count}} thành viên",
+    "deleteDescription": "Bạn có chắc chắn muốn xóa \"{{name}}\"? Tất cả thành viên, nhiệm vụ và cấu hình sẽ bị xóa vĩnh viễn.",
+    "tabs": {
+      "tasks": "Nhiệm vụ",
+      "members": "Thành viên",
+      "delegations": "Ủy quyền",
+      "settings": "Cài đặt"
+    }
+  },
+  "members": {
+    "title": "Thành viên",
+    "noMembers": "Không có thành viên",
+    "addMember": "Thêm thành viên",
+    "addMemberTooltip": "Chỉ có agent được định nghĩa sẵn mới có thể được thêm vào nhóm. Agent mở là per-user và thiếu ngữ cảnh dùng chung cần thiết cho cộng tác nhóm.",
+    "selectAgent": "Chọn agent để thêm...",
+    "noAvailableAgents": "Không có agent khả dụng",
+    "searchAgents": "Tìm kiếm agent...",
+    "adding": "Đang thêm...",
+    "add": "Thêm",
+    "removeMember": "Xóa thành viên",
+    "columns": {
+      "agent": "Agent",
+      "frontmatter": "Frontmatter",
+      "role": "Vai trò",
+      "addedAt": "Ngày thêm",
+      "actions": "Thao tác"
+    }
+  },
+  "tasks": {
+    "title": "Nhiệm vụ",
+    "loading": "Đang tải nhiệm vụ...",
+    "noTasks": "Chưa có nhiệm vụ",
+    "noTasksDescription": "Nhiệm vụ được tạo bởi agent nhóm trong quá trình cộng tác.",
+    "refresh": "Làm mới",
+    "columns": {
+      "subject": "Tiêu đề",
+      "status": "Trạng thái",
+      "owner": "Người phụ trách",
+      "priority": "Độ ưu tiên",
+      "taskId": "ID nhiệm vụ",
+      "created": "Đã tạo",
+      "actions": "Thao tác"
+    },
+    "detail": {
+      "title": "Chi tiết nhiệm vụ",
+      "subject": "Tiêu đề",
+      "status": "Trạng thái:",
+      "priority": "Độ ưu tiên:",
+      "owner": "Người phụ trách:",
+      "blockedBy": "Bị chặn bởi:",
+      "description": "Mô tả",
+      "result": "Kết quả",
+      "created": "Đã tạo:",
+      "updated": "Đã cập nhật:",
+      "taskId": "ID nhiệm vụ:",
+      "noDescription": "Không có mô tả",
+      "noResult": "Chưa có kết quả"
+    }
+  },
+  "delegations": {
+    "noTitle": "Không có ủy quyền",
+    "noDescription": "Không tìm thấy bản ghi ủy quyền nào cho Team này.",
+    "refresh": "Làm mới",
+    "columns": {
+      "sourceTarget": "Nguồn / Đích",
+      "task": "Nhiệm vụ",
+      "status": "Trạng thái",
+      "duration": "Thời lượng",
+      "time": "Thời gian"
+    }
+  },
+  "settings": {
+    "title": "Cài đặt nhóm",
+    "name": "Tên",
+    "displayName": "Tên hiển thị",
+    "description": "Mô tả",
+    "leadAgent": "Agent trưởng nhóm",
+    "status": "Trạng thái",
+    "active": "Hoạt động",
+    "inactive": "Không hoạt động",
+    "save": "Lưu cài đặt",
+    "saving": "Đang lưu...",
+    "saved": "Đã lưu",
+    "failedSave": "Lưu thất bại",
+    "userAccessControl": "Kiểm soát truy cập người dùng",
+    "allowedUsers": "Người dùng được phép",
+    "allowedUsersHint": "Nếu được đặt, chỉ những người dùng này mới có thể kích hoạt quy trình nhóm. Để trống = tất cả được phép.",
+    "deniedUsers": "Người dùng bị từ chối",
+    "deniedUsersHint": "Luôn bị chặn, ghi đè danh sách cho phép.",
+    "channelRestrictions": "Hạn chế channel",
+    "allowedChannels": "Channel được phép",
+    "allowedChannelsHint": "Nếu được đặt, chỉ những channel này mới có thể kích hoạt quy trình nhóm. Để trống = tất cả được phép.",
+    "deniedChannels": "Channel bị từ chối",
+    "deniedChannelsHint": "Tin nhắn từ các channel này luôn bị chặn.",
+    "notifications": "Thông báo",
+    "progressNotifications": "Thông báo tiến trình",
+    "progressNotificationsHint": "Gửi định kỳ thông báo \"Team của bạn đang xử lý...\" trong quá trình ủy quyền bất đồng bộ.",
+    "searchUsers": "Tìm kiếm người dùng...",
+    "selectChannel": "Chọn channel..."
+  },
+  "create": {
+    "title": "Tạo Team",
+    "name": "Tên *",
+    "namePlaceholder": "vd: Research Team",
+    "nameHint": "Chữ thường, số, dấu gạch ngang",
+    "description": "Mô tả",
+    "descriptionPlaceholder": "Mô tả nhóm tùy chọn...",
+    "leadAgent": "Agent trưởng nhóm *",
+    "selectLeadAgent": "Chọn agent trưởng nhóm...",
+    "loadingAgents": "Đang tải agent...",
+    "noActiveAgents": "Không tìm thấy agent hoạt động. Hãy tạo agent trước.",
+    "members": "Thành viên",
+    "membersTooltip": "Chỉ có agent được định nghĩa sẵn mới có thể được thêm vào nhóm. Agent mở là per-user và thiếu ngữ cảnh dùng chung.",
+    "searchMembers": "Tìm kiếm và thêm thành viên...",
+    "displayName": "Tên hiển thị",
+    "displayNamePlaceholder": "Support Team",
+    "cancel": "Hủy",
+    "create": "Tạo",
+    "creating": "Đang tạo..."
+  },
+  "toast": {
+    "created": "Đã tạo nhóm",
+    "deleted": "Đã xóa nhóm",
+    "updated": "Đã cập nhật nhóm",
+    "memberAdded": "Đã thêm thành viên",
+    "memberRemoved": "Đã xóa thành viên",
+    "failedCreate": "Không thể tạo nhóm",
+    "failedDelete": "Không thể xóa nhóm",
+    "failedUpdate": "Không thể cập nhật nhóm",
+    "failedAddMember": "Không thể thêm thành viên",
+    "failedRemoveMember": "Không thể xóa thành viên"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/tools.json b/ui/web/src/i18n/locales/vi/tools.json
new file mode 100644
index 00000000..f81854fe
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/tools.json
@@ -0,0 +1,156 @@
+{
+  "custom": {
+    "title": "Công cụ tùy chỉnh",
+    "description": "Quản lý các công cụ shell tùy chỉnh cho agent",
+    "createTool": "Tạo công cụ",
+    "searchPlaceholder": "Tìm kiếm công cụ...",
+    "emptyTitle": "Không có công cụ tùy chỉnh",
+    "emptyDescription": "Tạo công cụ tùy chỉnh đầu tiên để bắt đầu.",
+    "noMatchTitle": "Không tìm thấy công cụ phù hợp",
+    "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+    "noDescription": "Không có mô tả",
+    "columns": {
+      "name": "Tên",
+      "description": "Mô tả",
+      "scope": "Phạm vi",
+      "enabled": "Bật",
+      "timeout": "Thời gian chờ",
+      "actions": "Thao tác"
+    },
+    "scope": {
+      "agent": "Agent",
+      "global": "Toàn cục"
+    },
+    "delete": {
+      "title": "Xóa công cụ tùy chỉnh",
+      "description": "Bạn có chắc muốn xóa \"{{name}}\"? Hành động này không thể hoàn tác.",
+      "confirmLabel": "Xóa"
+    },
+    "form": {
+      "createTitle": "Tạo công cụ tùy chỉnh",
+      "editTitle": "Chỉnh sửa công cụ",
+      "name": "Tên *",
+      "namePlaceholder": "my-tool",
+      "nameHint": "Chỉ chữ thường, số và dấu gạch ngang",
+      "description": "Mô tả",
+      "descriptionPlaceholder": "Công cụ này làm gì...",
+      "command": "Lệnh *",
+      "commandHint": "Mẫu shell. Dùng {{.key}} cho các placeholder tham số.",
+      "parameters": "Tham số (JSON Schema)",
+      "workingDir": "Thư mục làm việc",
+      "workingDirPlaceholder": "/path/to/dir",
+      "timeout": "Thời gian chờ (giây)",
+      "agentId": "Agent ID (tùy chọn)",
+      "agentIdPlaceholder": "Để trống cho phạm vi toàn cục",
+      "enabled": "Bật",
+      "cancel": "Hủy",
+      "create": "Tạo",
+      "update": "Cập nhật",
+      "saving": "Đang lưu...",
+      "errors": {
+        "nameRequired": "Tên và lệnh là bắt buộc",
+        "nameSlug": "Tên phải là slug hợp lệ (chữ thường, số, dấu gạch ngang)",
+        "invalidJson": "Tham số phải là JSON hợp lệ"
+      }
+    },
+    "toast": {
+      "created": "Đã tạo công cụ",
+      "createdDesc": "{{name}} đã được thêm",
+      "updated": "Đã cập nhật công cụ",
+      "deleted": "Đã xóa công cụ",
+      "failedCreate": "Không thể tạo công cụ",
+      "failedUpdate": "Không thể cập nhật công cụ",
+      "failedDelete": "Không thể xóa công cụ"
+    }
+  },
+  "builtin": {
+    "title": "Công cụ tích hợp",
+    "description": "Quản lý các công cụ tích hợp sẵn. Bật/tắt hoặc cấu hình cài đặt toàn cục.",
+    "searchPlaceholder": "Tìm kiếm công cụ...",
+    "emptyTitle": "Không có công cụ tích hợp",
+    "emptyDescription": "Chưa có công cụ tích hợp nào được khởi tạo.",
+    "noMatchTitle": "Không tìm thấy công cụ phù hợp",
+    "noMatchDescription": "Thử từ khóa tìm kiếm khác.",
+    "toolCount": "{{count}} công cụ",
+    "toolCountPlural": "{{count}} công cụ",
+    "categoryCount": "{{count}} danh mục",
+    "requires": "yêu cầu",
+    "requiresTooltip": "Yêu cầu: {{list}}",
+    "settings": "Cài đặt",
+    "configuredVia": "Cấu hình qua trang Config",
+    "categories": {
+      "filesystem": "Hệ thống tệp",
+      "runtime": "Thời gian chạy",
+      "web": "Web",
+      "memory": "Bộ nhớ",
+      "media": "Phương tiện",
+      "browser": "Trình duyệt",
+      "sessions": "Session",
+      "messaging": "Nhắn tin",
+      "scheduling": "Lập lịch",
+      "subagents": "Agent",
+      "skills": "Skill",
+      "delegation": "Ủy quyền",
+      "teams": "Nhóm"
+    },
+    "settingsDialog": {
+      "title": "Cài đặt — {{name}}",
+      "cancel": "Hủy",
+      "save": "Lưu",
+      "saving": "Đang lưu...",
+      "noFields": "Không có cài đặt có thể cấu hình cho công cụ này.",
+      "toast": {
+        "saved": "Đã lưu cài đặt",
+        "failed": "Không thể lưu cài đặt"
+      }
+    },
+    "jsonDialog": {
+      "title": "Cài đặt: {{name}}",
+      "description": "Chỉnh sửa cài đặt công cụ dưới dạng JSON. Thay đổi có hiệu lực ngay sau khi lưu.",
+      "formatJson": "Định dạng JSON",
+      "invalidJsonSyntax": "Cú pháp JSON không hợp lệ",
+      "invalidJson": "JSON không hợp lệ",
+      "cannotFormat": "Không thể định dạng: JSON không hợp lệ",
+      "cancel": "Hủy",
+      "save": "Lưu",
+      "saving": "Đang lưu..."
+    },
+    "kgSettings": {
+      "title": "Cài đặt đồ thị tri thức",
+      "description": "Cấu hình trích xuất thực thể từ lần ghi bộ nhớ. Yêu cầu provider/mô hình hỗ trợ đầu ra JSON có cấu trúc.",
+      "extractionProvider": "Provider trích xuất",
+      "extractionModel": "Mô hình trích xuất",
+      "providerTip": "Provider LLM dùng để trích xuất thực thể và quan hệ từ văn bản.",
+      "modelTip": "ID mô hình để trích xuất. Nên hỗ trợ đầu ra JSON có cấu trúc.",
+      "minConfidence": "Độ tin cậy tối thiểu",
+      "minConfidenceHint": "Các thực thể dưới điểm tin cậy này sẽ bị loại bỏ (0,0–1,0).",
+      "autoExtract": "Tự động trích xuất khi ghi bộ nhớ",
+      "autoExtractHint": "Tự động trích xuất thực thể khi agent ghi vào tệp bộ nhớ.",
+      "cancel": "Hủy",
+      "save": "Lưu",
+      "saving": "Đang lưu..."
+    },
+    "mediaChain": {
+      "providerChainSuffix": "— Chuỗi provider",
+      "description": "Cấu hình và sắp xếp các provider dự phòng. Kéo để sắp xếp lại — provider đầu tiên được thử trước.",
+      "newProvider": "Provider mới",
+      "provider": "Provider",
+      "model": "Mô hình",
+      "selectProvider": "Chọn provider",
+      "loadingModels": "Đang tải...",
+      "selectModel": "Chọn mô hình",
+      "timeout": "Thời gian chờ",
+      "retries": "Số lần thử lại",
+      "settings": "Cài đặt",
+      "noProviders": "Chưa có provider nào. Thêm bên dưới.",
+      "addProvider": "Thêm provider",
+      "cancel": "Hủy",
+      "save": "Lưu",
+      "saving": "Đang lưu..."
+    },
+    "toast": {
+      "toggled": "Đã cập nhật công cụ",
+      "failedToggle": "Không thể cập nhật công cụ"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/topbar.json b/ui/web/src/i18n/locales/vi/topbar.json
new file mode 100644
index 00000000..7083f402
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/topbar.json
@@ -0,0 +1,16 @@
+{
+  "collapseSidebar": "Thu gọn thanh bên",
+  "expandSidebar": "Mở rộng thanh bên",
+  "language": "Ngôn ngữ",
+  "languages": {
+    "en": "English",
+    "vi": "Tiếng Việt",
+    "zh": "中文"
+  },
+  "logout": "Đăng xuất",
+  "openMenu": "Mở menu",
+  "pairingRequests": "Yêu cầu ghép nối",
+  "pendingPairingRequest": "{{count}} yêu cầu ghép nối đang chờ",
+  "pendingPairingRequests": "{{count}} yêu cầu ghép nối đang chờ",
+  "toggleTheme": "Chuyển đổi giao diện"
+}
diff --git a/ui/web/src/i18n/locales/vi/traces.json b/ui/web/src/i18n/locales/vi/traces.json
new file mode 100644
index 00000000..e5e1efec
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/traces.json
@@ -0,0 +1,49 @@
+{
+  "title": "Theo dõi",
+  "description": "Theo dõi lệnh gọi LLM và dữ liệu hiệu suất",
+  "filterPlaceholder": "Lọc theo agent ID...",
+  "filter": "Lọc",
+  "emptyTitle": "Không có dữ liệu theo dõi",
+  "emptyDescription": "Không tìm thấy dữ liệu theo dõi. Theo dõi được ghi lại khi agent xử lý yêu cầu.",
+  "columns": {
+    "name": "Tên",
+    "status": "Trạng thái",
+    "duration": "Thời lượng",
+    "tokens": "Token",
+    "spans": "Khoảng",
+    "time": "Thời gian"
+  },
+  "unnamed": "Không tên",
+  "cached": "đã cache",
+  "detail": {
+    "title": "Chi tiết theo dõi",
+    "copyTraceId": "Sao chép ID theo dõi",
+    "notFound": "Không tìm thấy theo dõi.",
+    "name": "Tên:",
+    "status": "Trạng thái:",
+    "duration": "Thời lượng:",
+    "channel": "Channel:",
+    "tokens": "Token:",
+    "spans": "Khoảng:",
+    "started": "Bắt đầu:",
+    "delegatedFrom": "Ủy quyền từ:",
+    "input": "Đầu vào",
+    "output": "Đầu ra",
+    "spansCount": "Khoảng ({{count}})",
+    "llmCalls": "LLM",
+    "toolCalls": "công cụ"
+  },
+  "span": {
+    "model": "Model:",
+    "tokens": "Token:",
+    "input": "Đầu vào:",
+    "output": "Đầu ra:",
+    "cacheRead": "đọc",
+    "cacheWrite": "ghi",
+    "thinking": "suy nghĩ",
+    "cached": "đã cache"
+  },
+  "toast": {
+    "failedLoad": "Không thể tải dữ liệu theo dõi"
+  }
+}
diff --git a/ui/web/src/i18n/locales/vi/tts.json b/ui/web/src/i18n/locales/vi/tts.json
new file mode 100644
index 00000000..0dc98e27
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/tts.json
@@ -0,0 +1,71 @@
+{
+  "autoModes": {
+    "always": "Luôn luôn",
+    "alwaysDesc": "Tất cả phản hồi đều có âm thanh",
+    "inbound": "Đầu vào",
+    "inboundDesc": "Chỉ khi người dùng gửi giọng nói/âm thanh",
+    "off": "Tắt",
+    "offDesc": "Agent có thể dùng công cụ TTS thủ công",
+    "tagged": "Đánh dấu",
+    "taggedDesc": "Chỉ khi phản hồi chứa thẻ [[tts]]"
+  },
+  "description": "Cấu hình provider TTS và cài đặt tự động",
+  "edge": {
+    "hint": "Edge TTS miễn phí, không cần API key.",
+    "speechRate": "Tốc độ nói",
+    "voice": "Giọng nói"
+  },
+  "elevenlabs": {
+    "apiKey": "API Key",
+    "baseUrl": "Base URL",
+    "modelId": "Model ID",
+    "voiceId": "Voice ID"
+  },
+  "general": {
+    "autoApplyMode": "Chế độ tự động phát",
+    "maxTextLength": "Độ dài text tối đa",
+    "primaryProvider": "Provider chính",
+    "replyMode": "Chế độ trả lời",
+    "timeout": "Thời gian chờ",
+    "title": "Cài đặt chung"
+  },
+  "minimax": {
+    "apiBase": "API Base",
+    "apiKey": "API Key",
+    "groupId": "Group ID",
+    "groupIdPlaceholder": "Nhập Group ID",
+    "model": "Model",
+    "voiceId": "Voice ID"
+  },
+  "openai": {
+    "apiBase": "API Base",
+    "apiKey": "API Key",
+    "model": "Model",
+    "voice": "Giọng nói"
+  },
+  "providerSettings": "Cài đặt {{provider}}",
+  "providers": {
+    "edge": "Edge (Miễn phí)",
+    "elevenlabs": "ElevenLabs",
+    "minimax": "MiniMax",
+    "none": "Không có (Tắt)",
+    "openai": "OpenAI"
+  },
+  "replyModes": {
+    "all": "Tất cả",
+    "allDesc": "Tất cả phản hồi bao gồm công cụ/khối",
+    "final": "Chỉ phản hồi cuối",
+    "finalDesc": "Chỉ phản hồi cuối cùng"
+  },
+  "save": "Lưu",
+  "saveChanges": "Lưu thay đổi",
+  "saving": "Đang lưu...",
+  "status": {
+    "activeProvider": "Provider đang hoạt động",
+    "configured": "Đã cấu hình",
+    "disabled": "Đã tắt",
+    "noProvider": "Chưa cấu hình provider TTS",
+    "title": "Trạng thái"
+  },
+  "title": "Chuyển văn bản thành giọng nói"
+}
diff --git a/ui/web/src/i18n/locales/vi/usage.json b/ui/web/src/i18n/locales/vi/usage.json
new file mode 100644
index 00000000..725c69d4
--- /dev/null
+++ b/ui/web/src/i18n/locales/vi/usage.json
@@ -0,0 +1,21 @@
+{
+  "title": "Sử dụng",
+  "description": "Mức sử dụng token và chi phí theo agent",
+  "emptyTitle": "Không có dữ liệu sử dụng",
+  "emptyDescription": "Dữ liệu sử dụng sẽ xuất hiện ở đây sau khi agent xử lý yêu cầu.",
+  "recentRecords": "Bản ghi gần đây",
+  "summary": {
+    "sessions": "{{count}} phiên",
+    "inputTokens": "Token đầu vào",
+    "outputTokens": "Token đầu ra",
+    "total": "Tổng"
+  },
+  "columns": {
+    "agent": "Agent",
+    "model": "Model",
+    "provider": "Provider",
+    "input": "Đầu vào",
+    "output": "Đầu ra",
+    "total": "Tổng"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/agents.json b/ui/web/src/i18n/locales/zh/agents.json
new file mode 100644
index 00000000..772b0088
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/agents.json
@@ -0,0 +1,342 @@
+{
+  "title": "Agent",
+  "description": "管理您的 AI Agent",
+  "createAgent": "创建Agent",
+  "searchPlaceholder": "搜索Agent...",
+  "emptyTitle": "暂无Agent",
+  "emptyDescription": "创建您的第一个Agent以开始使用。",
+  "noMatchTitle": "未找到匹配的Agent",
+  "noMatchDescription": "请尝试其他搜索词。",
+  "card": {
+    "unnamedAgent": "未命名Agent",
+    "summoning": "召唤中...",
+    "summonFailed": "失败",
+    "resummon": "重新召唤",
+    "delete": "删除",
+    "predefinedTooltip": "共享上下文文件 (SOUL.md, IDENTITY.md, AGENTS.md)，每用户有独立的 USER.md 实例。",
+    "openTooltip": "每个用户拥有完整的独立上下文文件集。",
+    "evolving": "进化中",
+    "static": "静态",
+    "evolvingTooltip": "Agent可以自我进化其沟通风格 (SOUL.md)。身份和工作流程保持不变。",
+    "staticTooltip": "Agent风格是静态的。在设置中启用自我进化以允许风格适应。"
+  },
+  "delete": {
+    "title": "删除Agent",
+    "description": "永久删除此Agent及其所有上下文文件、Session和配置。此操作无法撤销。",
+    "detailDescription": "确定要删除「{{name}}」吗？所有上下文文件、Session和配置将被永久删除。",
+    "confirmLabel": "删除",
+    "defaultCannotDelete": "默认Agent无法删除。"
+  },
+  "create": {
+    "title": "创建Agent",
+    "displayName": "显示名称 *",
+    "displayNamePlaceholder": "我的Agent",
+    "agentKey": "Agent标识 *",
+    "agentKeyPlaceholder": "例：my-agent",
+    "agentKeyHint": "小写字母、数字、连字符",
+    "provider": "Provider *",
+    "selectProvider": "选择Provider",
+    "model": "模型 *",
+    "enterOrSelectModel": "输入或选择模型",
+    "loadingModels": "加载模型中...",
+    "check": "检查",
+    "checking": "检查中...",
+    "modelVerified": "模型已验证",
+    "verificationFailed": "验证失败",
+    "noModelsHint": "此Provider不列出模型 — 请手动输入模型 ID。",
+    "agentType": "Agent类型",
+    "open": "开放型",
+    "openSubLabel": "每用户独立上下文",
+    "predefined": "预定义型",
+    "predefinedSubLabel": "Agent级配置",
+    "describeAgent": "描述您的Agent",
+    "descriptionPlaceholder": "描述Agent的性格、目的和行为...",
+    "descriptionHint": "AI 将根据此描述自动生成Agent的上下文文件。留空则使用模板。",
+    "selfEvolution": "自我进化",
+    "selfEvolutionHint": "允许Agent通过 SOUL.md 随时间进化其风格和语调",
+    "cancel": "取消",
+    "create": "创建",
+    "creating": "创建中...",
+    "checkAndCreate": "检查并创建",
+    "failedToCreate": "创建Agent失败"
+  },
+  "detail": {
+    "tabs": {
+      "general": "基本信息",
+      "config": "配置",
+      "files": "文件",
+      "shares": "共享",
+      "links": "链接",
+      "skills": "Skill",
+      "instances": "用户实例"
+    },
+    "summonFailed": "召唤失败",
+    "evolving": "进化中",
+    "static": "静态",
+    "evolvingTooltipDetail": "Agent可以自我进化其沟通风格 (SOUL.md)。身份和工作流程保持不变。",
+    "staticTooltipDetail": "Agent风格是静态的。在常规选项卡中启用自我进化以允许风格适应。"
+  },
+  "general": {
+    "selfEvolution": "自我进化",
+    "selfEvolutionLabel": "允许Agent进化其沟通风格",
+    "selfEvolutionHint": "启用后，Agent可以更新其 SOUL.md 以根据交互改善语调、词汇和响应风格。身份、名称和操作指令保持锁定。",
+    "selfEvolutionInfo": "Agent将通过 SOUL.md 更新随时间进化其风格。只有风格和语调受影响 — 身份和工作流规则保持固定。",
+    "saveChanges": "保存更改",
+    "saving": "保存中...",
+    "saved": "已保存",
+    "failedToSave": "保存失败"
+  },
+  "identity": {
+    "title": "身份",
+    "agentKey": "Agent标识",
+    "agentKeyHint": "唯一标识符，无法更改。",
+    "displayName": "显示名称",
+    "displayNamePlaceholder": "例：我的助手",
+    "displayNameHint": "在界面中显示的友好名称。留空则使用Agent标识。",
+    "expertiseSummary": "专业摘要",
+    "expertiseSummaryPlaceholder": "例：数据分析、代码审查、技术文档",
+    "expertiseSummaryHint": "对该Agent专业领域的简短描述，用于委派发现。",
+    "status": "状态",
+    "active": "活跃",
+    "inactive": "非活跃",
+    "summonFailed": "召唤失败",
+    "defaultAgent": "默认Agent"
+  },
+  "llmConfig": {
+    "title": "LLM 配置",
+    "contextWindow": "上下文窗口",
+    "contextWindowHint": "模型上下文的令牌限制。",
+    "maxToolIterations": "最大工具迭代次数",
+    "maxToolIterationsHint": "每次请求最大工具调用次数。"
+  },
+  "workspace": {
+    "title": "工作区",
+    "workspacePath": "工作区路径",
+    "workspacePathHint": "创建Agent时自动分配。运行时创建每用户子目录。",
+    "noWorkspace": "未配置工作区",
+    "restrictToWorkspace": "限制在工作区内",
+    "restrictToWorkspaceHint": "严格限制文件访问在工作区路径内。"
+  },
+  "config": {
+    "saveConfig": "保存配置",
+    "saving": "保存中...",
+    "saved": "已保存",
+    "failedToSave": "保存失败",
+    "usingGlobalDefaults": "使用 config.json 中的全局默认值"
+  },
+  "files": {
+    "readOnly": "只读",
+    "readOnlyDesc": "只有Agent所有者才能编辑预定义上下文文件。",
+    "resummon": "重新召唤",
+    "editWithAi": "AI 编辑",
+    "resummonTitle": "重新召唤Agent",
+    "resummonDesc": "这将使用原始描述从头重新生成 SOUL.md、IDENTITY.md 和可选的 USER_PREDEFINED.md。对这些文件的任何手动编辑都将被覆盖。",
+    "cancel": "取消",
+    "resummonConfirm": "重新召唤",
+    "summoning": "召唤中...",
+    "selectFileToEdit": "选择文件以编辑",
+    "selectFileToView": "选择文件以查看",
+    "saving": "保存中...",
+    "save": "保存",
+    "loading": "加载中...",
+    "openAgentTitle": "开放型Agent - 每用户上下文文件",
+    "openAgentDesc1": "这是一个开放型Agent。上下文文件（AGENTS.md、SOUL.md、TOOLS.md 等）为每个用户个性化定制。当用户首次与此Agent聊天时，会从模板自动创建这些文件。",
+    "openAgentDesc2pre": "此处显示的Agent级文件为空，因为开放型Agent将所有上下文按用户存储在 ",
+    "openAgentDesc2post": " 表中。",
+    "contextFiles": "上下文文件",
+    "contextFile": "上下文文件",
+    "perUser": "每用户",
+    "emptyFile": "空",
+    "estTokens": "估计 {{tokens}} token"
+  },
+  "fileEditor": {
+    "editWithAi": "AI 编辑",
+    "editAiDescription": "描述您想要更改的内容。AI 将读取当前文件并相应更新。",
+    "editAiPlaceholder": "例：使Agent更正式，添加中文支持，将名称更改为 Luna...",
+    "sending": "发送中...",
+    "regenerate": "重新生成",
+    "cancel": "取消"
+  },
+  "shares": {
+    "grantAccess": "授予访问权限",
+    "userId": "用户 ID",
+    "userIdPlaceholder": "输入用户 ID...",
+    "role": "角色",
+    "share": "共享",
+    "loadingShares": "加载共享中...",
+    "noShares": "暂无共享",
+    "noSharesDesc": "通过上方输入用户 ID 与其他用户共享此Agent。",
+    "user": "用户",
+    "revokeTitle": "撤销共享",
+    "revokeDesc": "撤销用户「{{userId}}」的访问权限？他们将无法再使用此Agent。",
+    "revoke": "撤销"
+  },
+  "links": {
+    "teamsHint": "对于具有任务跟踪和质量控制的多Agent协作，请考虑使用Agent Team。Agent链接最适合两个Agent之间的简单一对一委派。",
+    "createLink": "创建链接",
+    "targetAgent": "目标Agent",
+    "selectAgent": "选择或搜索Agent...",
+    "direction": "方向",
+    "description": "描述",
+    "descriptionPlaceholder": "链接的可选描述...",
+    "maxConcurrent": "最大并发数",
+    "advancedSettings": "高级设置",
+    "allowedUsers": "允许的用户",
+    "allowedUsersPlaceholder": "user1, user2, ...",
+    "allowedUsersHint": "如果设置，只有这些用户可以触发此委派。逗号分隔。",
+    "deniedUsers": "拒绝的用户",
+    "deniedUsersPlaceholder": "user3, user4, ...",
+    "deniedUsersHint": "这些用户被阻止触发此委派。逗号分隔。",
+    "creating": "创建中...",
+    "noLinks": "暂无Agent链接",
+    "noLinksDesc": "创建链接以允许Agent相互委派任务。",
+    "loadingLinks": "加载链接中...",
+    "columns": {
+      "target": "目标",
+      "direction": "方向",
+      "status": "状态",
+      "limit": "限制"
+    },
+    "deleteTitle": "删除链接",
+    "deleteDesc": "删除到「{{name}}」的委派链接？Agent将无法再通过此链接相互委派。",
+    "editTitle": "编辑链接",
+    "editDescription": "更新委派链接设置。",
+    "optionalDescription": "可选描述...",
+    "allowedUsersHintShort": "如果设置，只有这些用户可以触发此委派。",
+    "deniedUsersHintShort": "这些用户被阻止触发此委派。"
+  },
+  "skills": {
+    "noSkillsAvailable": "无可用Skill",
+    "noSkillsDesc": "在Skill页面上传Skill以授予Agent。",
+    "skillsGranted": "已授予 {{granted}} / {{total}} 个Skill",
+    "filterSkills": "筛选Skill...",
+    "noSkillsMatch": "没有Skill匹配您的搜索。"
+  },
+  "instances": {
+    "loadingInstances": "加载实例中...",
+    "noInstances": "暂无用户实例。",
+    "noInstancesDesc": "当用户与此Agent交互时会创建实例。",
+    "instanceCount": "{{count}} 个实例",
+    "instanceCount_plural": "{{count}} 个实例",
+    "selectInstance": "选择实例以查看和编辑其 USER.md",
+    "loading": "加载中...",
+    "saving": "保存中...",
+    "save": "保存",
+    "saved": "已保存"
+  },
+  "summoning": {
+    "title": "正在召唤您的Agent...",
+    "completed": "召唤完成！",
+    "failed": "召唤失败",
+    "agentReady": "{{name}} 已就绪！",
+    "weavingSoul": "正在为以下Agent织入灵魂：",
+    "wait": "通常需要几分钟，请耐心等待...",
+    "continue": "继续",
+    "retry": "重试",
+    "retrying": "重试中...",
+    "done": "完成"
+  },
+  "configSections": {
+    "subagents": {
+      "title": "子Agent",
+      "description": "控制子Agent生成限制和行为",
+      "maxConcurrent": "最大并发数",
+      "maxSpawnDepth": "最大生成深度",
+      "maxChildrenPerAgent": "每Agent最大子数",
+      "archiveAfter": "归档时间（分钟）",
+      "modelOverride": "模型覆盖",
+      "inheritFromAgent": "（继承自Agent）"
+    },
+    "toolPolicy": {
+      "title": "工具策略",
+      "description": "控制此Agent可以使用哪些工具",
+      "profile": "配置文件",
+      "allow": "允许",
+      "deny": "拒绝",
+      "alsoAllow": "同时允许",
+      "selectToolsAllow": "选择要允许的工具...",
+      "selectToolsDeny": "选择要拒绝的工具...",
+      "selectToolsAlsoAllow": "选择附加工具..."
+    },
+    "compaction": {
+      "title": "压缩",
+      "description": "上下文窗口压缩和内存刷新设置",
+      "reserveTokensFloor": "保留令牌下限",
+      "maxHistoryShare": "最大历史份额 (0-1)",
+      "minMessages": "最小消息数",
+      "keepLastMessages": "保留最后消息数",
+      "memoryFlush": "内存刷新",
+      "softThreshold": "软阈值（令牌）"
+    },
+    "contextPruning": {
+      "title": "上下文裁剪",
+      "description": "裁剪旧工具结果以节省上下文窗口",
+      "mode": "模式",
+      "keepLastAssistants": "保留最后助手数",
+      "softTrimRatio": "软裁剪比例 (0-1)",
+      "hardClearRatio": "硬清除比例 (0-1)",
+      "minPrunableToolChars": "最小可裁剪工具字符数",
+      "softTrim": "软裁剪",
+      "maxChars": "最大字符数",
+      "headChars": "头部字符数",
+      "tailChars": "尾部字符数",
+      "hardClear": "硬清除",
+      "enabled": "已启用",
+      "placeholderText": "占位符文本"
+    },
+    "sandbox": {
+      "title": "沙箱",
+      "description": "用于代码执行隔离的 Docker 沙箱",
+      "mode": "模式",
+      "workspaceAccess": "工作区访问",
+      "image": "镜像",
+      "scope": "范围",
+      "timeout": "超时（秒）",
+      "memoryMb": "内存（MB）",
+      "cpus": "CPU",
+      "networkEnabled": "启用网络"
+    },
+    "memory": {
+      "title": "记忆",
+      "description": "语义记忆搜索和嵌入配置",
+      "embeddingProvider": "嵌入Provider",
+      "embeddingModel": "嵌入模型",
+      "maxResults": "最大结果数",
+      "maxChunkLen": "最大块长度",
+      "vectorWeight": "向量权重",
+      "textWeight": "文本权重"
+    },
+    "thinking": {
+      "title": "扩展思考",
+      "description": "允许模型在响应前进行推理。更高级别使用更多令牌，但在复杂任务上产生更好的结果。",
+      "thinkingLevel": "思考级别",
+      "off": "关闭",
+      "offDesc": "无扩展思考",
+      "low": "低",
+      "lowDesc": "~4K 令牌预算",
+      "medium": "中",
+      "mediumDesc": "~10-16K 令牌预算",
+      "high": "高",
+      "highDesc": "~32K 令牌预算"
+    },
+    "qualityGates": {
+      "title": "质量门控",
+      "description": "在返回给调用者之前验证委派输出",
+      "noGates": "未配置质量门控。点击「添加门控」创建。",
+      "addGate": "添加门控",
+      "gateNumber": "门控 #{{number}}",
+      "type": "类型",
+      "reviewerAgentKey": "审查Agent标识",
+      "command": "命令",
+      "blockOnFailure": "失败时阻止",
+      "maxRetries": "最大重试次数",
+      "timeout": "超时（秒）"
+    },
+    "otherConfig": {
+      "title": "其他配置",
+      "description": "其他部分未涵盖的高级设置的额外 JSON 配置",
+      "formatJson": "格式化 JSON",
+      "invalidJson": "JSON 语法无效"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/approvals.json b/ui/web/src/i18n/locales/zh/approvals.json
new file mode 100644
index 00000000..4d8d193b
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/approvals.json
@@ -0,0 +1,23 @@
+{
+  "title": "审批",
+  "description": "待处理的执行审批",
+  "pending": "{{count}} 个待处理",
+  "emptyTitle": "暂无待处理审批",
+  "emptyDescription": "所有执行请求已处理完毕。新请求将实时显示在此处。",
+  "allowOnce": "允许一次",
+  "allowAlways": "始终允许",
+  "deny": "拒绝",
+  "confirmAllowOnce": {
+    "title": "允许一次",
+    "description": "允许来自Agent 「{{agentId}}」 的 「{{command}}」 执行请求？"
+  },
+  "confirmAllowAlways": {
+    "title": "始终允许",
+    "description": "永久允许Agent 「{{agentId}}」 执行 「{{command}}」？此命令将在未来自动批准。"
+  },
+  "confirmDeny": {
+    "title": "拒绝执行",
+    "description": "拒绝来自Agent 「{{agentId}}」 的 「{{command}}」 执行请求？",
+    "confirmLabel": "拒绝"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/channels.json b/ui/web/src/i18n/locales/zh/channels.json
new file mode 100644
index 00000000..19178648
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/channels.json
@@ -0,0 +1,213 @@
+{
+  "title": "Channel",
+  "description": "管理Channel实例",
+  "statusDescription": "通信Channel状态",
+  "addChannel": "添加Channel",
+  "refresh": "刷新",
+  "searchPlaceholder": "搜索Channel...",
+  "emptyTitle": "暂无Channel",
+  "emptyDescription": "添加您的第一个Channel实例以开始使用。",
+  "emptyStatusDescription": "未配置任何通信Channel。",
+  "noMatchTitle": "未找到匹配Channel",
+  "noMatchDescription": "请尝试其他搜索词。",
+  "columns": {
+    "name": "名称",
+    "type": "类型",
+    "agent": "Agent",
+    "status": "状态",
+    "enabled": "已启用",
+    "actions": "操作"
+  },
+  "status": {
+    "running": "运行中",
+    "stopped": "已停止"
+  },
+  "enabled": "已启用",
+  "disabled": "已禁用",
+  "actions": {
+    "reauthenticate": "重新认证",
+    "authenticate": "认证以启动Channel"
+  },
+  "delete": {
+    "title": "删除Channel实例",
+    "description": "确定要删除「{{name}}」吗？此操作无法撤销。",
+    "confirmLabel": "删除"
+  },
+  "form": {
+    "createTitle": "创建Channel实例",
+    "editTitle": "编辑Channel实例",
+    "key": "键 *",
+    "keyPlaceholder": "my-telegram-bot",
+    "keyHint": "用作Channel标识符的唯一 slug",
+    "displayName": "显示名称",
+    "displayNamePlaceholder": "Sales Bot",
+    "channelType": "Channel类型 *",
+    "agent": "Agent *",
+    "selectAgent": "选择Agent",
+    "credentials": "凭据",
+    "credentialsHint": "（留空以保留当前值）",
+    "credentialsEncrypted": "在服务器端加密，不会在 API 响应中返回。",
+    "configuration": "配置",
+    "enabled": "已启用",
+    "cancel": "取消",
+    "create": "创建",
+    "update": "更新",
+    "saving": "保存中...",
+    "step": "第 {{current}} 步，共 {{total}} 步",
+    "authenticate": "认证 — {{label}}",
+    "configure": "配置 — {{label}}",
+    "skip": "跳过",
+    "done": "完成",
+    "errors": {
+      "keyRequired": "键为必填项",
+      "keySlug": "键必须是有效的 slug（小写字母、数字、连字符）",
+      "agentRequired": "Agent为必填项",
+      "requiredFields": "必填: {{fields}}",
+      "failedSave": "保存失败",
+      "failedSaveConfig": "保存配置失败"
+    },
+    "authStatus": {
+      "authenticated": "已认证",
+      "notAuthenticated": "未认证",
+      "useQrHint": "— 使用Channel表中的 QR 登录按钮"
+    }
+  },
+  "detail": {
+    "agent": "Agent: {{name}}",
+    "tabs": {
+      "general": "基本信息",
+      "config": "配置",
+      "credentials": "凭据",
+      "groups": "群组",
+      "writers": "写入权限"
+    },
+    "general": {
+      "name": "名称",
+      "nameHint": "唯一标识（只读）",
+      "channelType": "Channel类型",
+      "displayName": "显示名称",
+      "displayNamePlaceholder": "友好名称",
+      "agent": "Agent",
+      "selectAgent": "选择Agent",
+      "enabled": "已启用",
+      "saved": "已保存",
+      "saveChanges": "保存更改",
+      "saving": "保存中..."
+    },
+    "credentials": {
+      "hint": "留空字段以保留当前值。凭据在服务器端加密，不会在 API 响应中返回。",
+      "noSchema": "此Channel类型没有凭据模式。",
+      "noCredentials": "没有要更新的凭据",
+      "failedSave": "保存失败",
+      "saved": "已保存",
+      "updateCredentials": "更新凭据",
+      "saving": "保存中..."
+    },
+    "config": {
+      "noSchema": "此Channel类型没有配置模式。",
+      "saved": "已保存",
+      "saveConfig": "保存配置",
+      "saving": "保存中..."
+    },
+    "groups": {
+      "saved": "已保存",
+      "saveGroups": "保存群组",
+      "saving": "保存中..."
+    },
+    "writers": {
+      "description": "管理允许在群组聊天中写入/编辑文件的用户。",
+      "groups": "群组",
+      "noWriterGroups": "暂无写入权限群组",
+      "noWriterGroupsHint": "使用下方表单将写入权限添加到群组。",
+      "loadingWriters": "正在加载写入者...",
+      "noWriters": "此群组中没有写入者。",
+      "writersCount": "{{count}} 位写入者",
+      "writersCountPlural": "{{count}} 位写入者",
+      "columns": {
+        "userId": "用户 ID",
+        "name": "名称",
+        "username": "用户名"
+      },
+      "addForm": {
+        "title": "将写入者添加到新群组",
+        "hint": "将写入者添加到上方列表中未出现的群组。",
+        "groupId": "群组 ID *",
+        "groupIdPlaceholder": "例如 group:telegram:-100123456",
+        "userId": "用户 ID *",
+        "userIdPlaceholder": "例如 12345678",
+        "displayName": "显示名称",
+        "username": "用户名",
+        "optional": "可选",
+        "usernameWithout": "可选（不含 @）",
+        "adding": "添加中...",
+        "addWriter": "添加写入者",
+        "add": "添加",
+        "errors": {
+          "groupUserRequired": "群组 ID 和用户 ID 为必填项",
+          "failedAdd": "添加写入者失败"
+        }
+      }
+    }
+  },
+  "groupOverrides": {
+    "title": "群组和话题覆盖",
+    "hint": "按群组聊天或论坛话题覆盖Channel默认值。使用 「*」 作为群组 ID 表示通配符默认值。",
+    "groupLabel": "群组: {{id}}",
+    "groupWildcard": "* (通配符)",
+    "addGroupPlaceholder": "聊天 ID（例如 -100123456）或 *",
+    "addGroup": "添加群组",
+    "topicOverrides": "话题覆盖",
+    "topicLabel": "话题: {{id}}",
+    "addTopicPlaceholder": "话题线程 ID",
+    "addTopic": "添加话题",
+    "fields": {
+      "groupPolicy": "群组策略",
+      "requireMention": "需要 @提及",
+      "enabled": "已启用",
+      "allowedUsers": "允许的用户",
+      "allowedUsersPlaceholder": "每行一个用户 ID",
+      "skillsFilter": "Skill过滤",
+      "skillsPlaceholder": "每行一个Skill名称（空 = 继承）",
+      "toolAllow": "允许的工具",
+      "toolAllowPlaceholder": "选择允许的工具（空 = 继承所有）...",
+      "toolAllowHint": "限制此群组中可用的工具。支持群组名称如 「group:web」、「group:fs」。空 = 继承所有工具。",
+      "systemPrompt": "系统提示词",
+      "systemPromptPlaceholder": "此群组/话题的附加系统提示词",
+      "inherit": "继承（Channel默认）",
+      "yes": "是",
+      "no": "否"
+    }
+  },
+  "toast": {
+    "created": "Channel已创建",
+    "createdDesc": "{{name}} 已添加",
+    "updated": "Channel已更新",
+    "deleted": "Channel已删除",
+    "failedCreate": "创建Channel失败",
+    "failedUpdate": "更新Channel失败",
+    "failedDelete": "删除Channel失败"
+  },
+  "zalo": {
+    "allowedUsers": "允许的用户",
+    "loadContacts": "加载联系人",
+    "loading": "加载中...",
+    "searchContacts": "搜索联系人...",
+    "friends": "好友",
+    "groups": "群组",
+    "membersCount": "{{count}} 位成员",
+    "noContacts": "未找到联系人",
+    "noContactsMatch": "没有与「{{search}}」匹配的联系人",
+    "addManualPlaceholder": "手动添加 ID",
+    "add": "添加",
+    "zaloIdsHint": "Zalo 用户 ID 或群组 ID",
+    "completeQrLogin": "完成 QR 登录以加载联系人",
+    "loginQr": "QR 登录 — {{name}}",
+    "loginSuccessful": "登录成功！Channel正在启动...",
+    "generatingQr": "正在生成二维码...",
+    "scanHint": "使用 Zalo 应用扫描（约 100 秒后过期）",
+    "loginSuccessLoading": "登录成功！正在加载联系人...",
+    "retry": "重试",
+    "close": "关闭",
+    "skip": "跳过"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/chat.json b/ui/web/src/i18n/locales/zh/chat.json
new file mode 100644
index 00000000..b9328a3b
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/chat.json
@@ -0,0 +1,20 @@
+{
+  "empty": {
+    "description": "发送消息开始与Agent对话。",
+    "title": "开始对话"
+  },
+  "forwardedFrom": "转发自",
+  "media": {
+    "animation": "动画",
+    "attached": "已附加",
+    "audio": "音频",
+    "document": "文档",
+    "image": "图片",
+    "video": "视频",
+    "voice": "语音消息"
+  },
+  "newChat": "新建对话",
+  "openSessions": "打开Session",
+  "readOnly": "只读 — 此Session属于其他用户",
+  "replyingTo": "回复"
+}
diff --git a/ui/web/src/i18n/locales/zh/common.json b/ui/web/src/i18n/locales/zh/common.json
new file mode 100644
index 00000000..9272eedc
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/common.json
@@ -0,0 +1,104 @@
+{
+  "actions": "操作",
+  "active": "活跃",
+  "add": "添加",
+  "agent": "Agent",
+  "all": "全部",
+  "back": "返回",
+  "builtinTools": "内置",
+  "cached": "已缓存",
+  "cancel": "取消",
+  "cancelled": "已取消",
+  "check": "检查",
+  "checkAndCreate": "检查并创建",
+  "checking": "检查中...",
+  "close": "关闭",
+  "completed": "已完成",
+  "confirm": "确认",
+  "connected": "已连接",
+  "connecting": "连接中...",
+  "create": "创建",
+  "creating": "创建中...",
+  "customTools": "自定义",
+  "default": "默认",
+  "delete": "删除",
+  "description": "描述",
+  "disabled": "已禁用",
+  "disconnected": "已断开",
+  "disconnectedGateway": "已与网关断开连接。正在尝试重新连接...",
+  "edit": "编辑",
+  "enabled": "已启用",
+  "enterOrSelectModel": "输入或选择模型",
+  "failed": "已失败",
+  "filesBack": "文件",
+  "filter": "筛选",
+  "format": "格式化 JSON",
+  "global": "全局",
+  "invalidJson": "JSON 语法无效",
+  "items": "条",
+  "live": "实时",
+  "loading": "加载中...",
+  "loadingModels": "加载模型中...",
+  "manage": "管理",
+  "messages": "条消息",
+  "model": "模型",
+  "modelTip": "要使用的模型 ID。",
+  "modelVerified": "模型已验证",
+  "name": "名称",
+  "no": "否",
+  "noAgentsAvailable": "暂无可用Agent",
+  "noDescription": "暂无描述",
+  "noFiles": "未找到文件。",
+  "noProvidersConfigured": "未配置Provider",
+  "noSessions": "暂无Session。开始聊天！",
+  "none": "无",
+  "notSet": "未设置",
+  "optional": "可选",
+  "pageOf": "第 {{page}} / {{totalPages}} 页",
+  "pending": "等待中",
+  "provider": "Provider",
+  "providerTip": "LLM Provider名称。必须与已配置的Provider匹配。",
+  "refresh": "刷新",
+  "required": "必填",
+  "retry": "重试",
+  "rows": "行",
+  "running": "运行中",
+  "save": "保存",
+  "saveChanges": "保存更改",
+  "saveConfig": "保存配置",
+  "saved": "已保存",
+  "saving": "保存中...",
+  "search": "搜索...",
+  "searchPlaceholder": "搜索...",
+  "selectAgent": "选择Agent",
+  "selectFileToView": "选择文件以查看其内容",
+  "selectOrTypeTools": "选择或输入工具名称...",
+  "selectProvider": "选择Provider",
+  "sendMessage": "发送消息... (Shift+Enter 换行)",
+  "sendMessageTitle": "发送消息",
+  "skillActivated": "已激活",
+  "skillActivating": "激活中...",
+  "status": "状态",
+  "stopGeneration": "停止生成",
+  "stopped": "已停止",
+  "thinking": "思考中",
+  "thinkingStreaming": "思考中...",
+  "toolArguments": "参数",
+  "toolDone": "完成",
+  "toolFailed": "失败",
+  "toolResult": "结果",
+  "toolRunning": "运行中...",
+  "tryDifferentSearch": "请尝试不同的搜索关键词。",
+  "type": "类型",
+  "typeAndPressEnter": "输入并按 Enter...",
+  "typeToConfirmPrefix": "输入",
+  "typeToConfirmSuffix": "以确认。",
+  "unknown": "未知",
+  "unsavedChanges": "有未保存的更改",
+  "update": "更新",
+  "upload": "上传",
+  "usingGlobalDefaults": "使用 config.json 中的全局默认值",
+  "verificationFailed": "验证失败",
+  "view": "查看",
+  "yes": "是"
+}
diff --git a/ui/web/src/i18n/locales/zh/cron.json b/ui/web/src/i18n/locales/zh/cron.json
new file mode 100644
index 00000000..890e7d50
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/cron.json
@@ -0,0 +1,102 @@
+{
+  "title": "定时任务",
+  "description": "安排定期Agent任务",
+  "newJob": "新建任务",
+  "emptyTitle": "暂无定时任务",
+  "emptyDescription": "创建定时任务以安排定期Agent任务。",
+  "columns": {
+    "enabled": "已启用",
+    "name": "名称",
+    "schedule": "计划",
+    "message": "消息",
+    "agent": "Agent",
+    "actions": "操作"
+  },
+  "runNow": "立即运行",
+  "running": "运行中...",
+  "runHistory": "运行历史",
+  "defaultAgent": "默认",
+  "create": {
+    "title": "创建定时任务",
+    "name": "名称",
+    "namePlaceholder": "my-daily-task",
+    "nameHint": "仅小写字母、数字和连字符",
+    "agentId": "Agent ID（可选）",
+    "agentIdPlaceholder": "默认",
+    "scheduleType": "计划类型",
+    "every": "每隔",
+    "cron": "Cron",
+    "once": "一次",
+    "intervalSeconds": "间隔（秒）",
+    "cronExpression": "Cron 表达式",
+    "cronHint": "标准 5 字段 cron：分 时 日 月 周",
+    "onceDesc": "任务将运行一次，大约从现在起 1 分钟后。",
+    "message": "消息",
+    "messagePlaceholder": "Agent应该做什么？",
+    "cancel": "取消",
+    "create": "创建",
+    "creating": "创建中..."
+  },
+  "enable": {
+    "title": "启用定时任务",
+    "description": "启用「{{name}}」？它将开始按计划运行。",
+    "confirmLabel": "启用"
+  },
+  "disable": {
+    "title": "禁用定时任务",
+    "description": "禁用「{{name}}」？它将停止运行直到重新启用。",
+    "confirmLabel": "禁用"
+  },
+  "delete": {
+    "title": "删除定时任务",
+    "description": "删除「{{name}}」？此操作无法撤销。",
+    "confirmLabel": "删除"
+  },
+  "runLog": {
+    "title": "运行日志：{{name}}",
+    "noHistory": "暂无运行历史。",
+    "loading": "加载中..."
+  },
+  "detail": {
+    "runNow": "立即运行",
+    "running": "运行中...",
+    "disable": "禁用",
+    "enable": "启用",
+    "delete": "删除",
+    "enabled": "已启用",
+    "disabled": "已禁用",
+    "runningStatus": "运行中...",
+    "payload": "有效载荷",
+    "empty": "（空）",
+    "deliverDirect": "投递：直接",
+    "channel": "Channel：{{name}}",
+    "to": "至：{{name}}",
+    "lastError": "最后错误",
+    "runHistory": "运行历史",
+    "refresh": "刷新",
+    "noHistory": "暂无运行历史。",
+    "inOut": "{{input}} 输入 / {{output}} 输出",
+    "infoRows": {
+      "schedule": "计划",
+      "timezone": "时区",
+      "nextRun": "下次运行",
+      "lastRun": "上次运行",
+      "created": "创建时间",
+      "updated": "更新时间",
+      "autoDelete": "自动删除",
+      "autoDeleteValue": "是（一次性）"
+    }
+  },
+  "toast": {
+    "created": "定时任务已创建",
+    "createdDesc": "{{name}} 已添加",
+    "enabled": "定时任务已启用",
+    "disabled": "定时任务已禁用",
+    "deleted": "定时任务已删除",
+    "triggered": "定时任务已触发",
+    "failedCreate": "创建定时任务失败",
+    "failedToggle": "切换定时任务失败",
+    "failedDelete": "删除定时任务失败",
+    "failedRun": "运行定时任务失败"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/delegations.json b/ui/web/src/i18n/locales/zh/delegations.json
new file mode 100644
index 00000000..05644761
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/delegations.json
@@ -0,0 +1,41 @@
+{
+  "title": "委托",
+  "description": "Agent委托历史和结果",
+  "sourceFilterPlaceholder": "源Agent...",
+  "targetFilterPlaceholder": "目标Agent...",
+  "filter": "筛选",
+  "emptyTitle": "暂无委托",
+  "emptyDescription": "暂无委托记录。当Agent将任务委托给其他Agent时将自动记录。",
+  "columns": {
+    "sourceTarget": "源 / 目标",
+    "task": "任务",
+    "status": "状态",
+    "mode": "模式",
+    "duration": "耗时",
+    "time": "时间"
+  },
+  "statusFilter": {
+    "all": "全部",
+    "pending": "等待中",
+    "running": "运行中",
+    "completed": "已完成",
+    "failed": "已失败",
+    "cancelled": "已取消"
+  },
+  "detail": {
+    "title": "委托详情",
+    "notFound": "未找到委托。",
+    "source": "源：",
+    "target": "目标：",
+    "status": "状态：",
+    "mode": "模式：",
+    "duration": "耗时：",
+    "iterations": "迭代次数：",
+    "created": "创建时间：",
+    "completed": "完成时间：",
+    "trace": "追踪：",
+    "task": "任务",
+    "result": "结果",
+    "error": "错误"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/events.json b/ui/web/src/i18n/locales/zh/events.json
new file mode 100644
index 00000000..3adc4131
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/events.json
@@ -0,0 +1,34 @@
+{
+  "title": "实时事件",
+  "description": "所有Team和Agent的实时 WebSocket 事件",
+  "live": "实时",
+  "paused": "已暂停",
+  "resume": "恢复",
+  "pause": "暂停",
+  "clear": "清除",
+  "scrollToBottom": "滚动到底部",
+  "eventCount": "{{count}} 个事件",
+  "eventCountPlural": "{{count}} 个事件",
+  "categories": {
+    "all": "全部",
+    "delegation": "委托",
+    "task": "任务",
+    "message": "消息",
+    "agent": "Agent",
+    "teamCrud": "Team管理",
+    "agentLink": "Agent链接"
+  },
+  "filters": {
+    "allTeams": "所有Team",
+    "allUsers": "所有用户",
+    "allChats": "所有对话"
+  },
+  "global": "全局",
+  "emptyTitle": "暂无事件",
+  "emptyPaused": "事件捕获已暂停。恢复后可查看新事件。",
+  "emptyWaiting": "等待实时事件中... Agent运行时事件将显示在此处。",
+  "detail": {
+    "copy": "复制",
+    "copied": "已复制"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/login.json b/ui/web/src/i18n/locales/zh/login.json
new file mode 100644
index 00000000..664c2728
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/login.json
@@ -0,0 +1,32 @@
+{
+  "pairing": {
+    "approved": "访问已批准！正在跳转...",
+    "askAdmin": "请让管理员批准此配对码：",
+    "cancel": "取消",
+    "connecting": "连接中...",
+    "errorCannotConnect": "无法连接到 Gateway。",
+    "errorConnectionLost": "连接断开，请重试。",
+    "noTokenNeeded": "无需令牌。系统将生成配对码，由管理员批准。",
+    "orRun": "或执行命令：",
+    "requestAccess": "请求访问",
+    "userId": "用户 ID",
+    "userIdPlaceholder": "your-user-id",
+    "waitingForApproval": "等待审批中..."
+  },
+  "subtitle": "登录网关控制面板",
+  "tabs": {
+    "pairing": "配对",
+    "token": "令牌"
+  },
+  "token": {
+    "connect": "连接",
+    "connecting": "连接中...",
+    "errorCannotConnect": "无法连接到 Gateway。请检查服务器是否在运行。",
+    "errorInvalidCredentials": "凭据无效。请检查 Token 和 User ID。",
+    "errorServer": "服务器返回 {{status}}，请重试。",
+    "gatewayToken": "Gateway Token",
+    "tokenPlaceholder": "Bearer token",
+    "userId": "用户 ID",
+    "userIdPlaceholder": "您的用户 ID"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/logs.json b/ui/web/src/i18n/locales/zh/logs.json
new file mode 100644
index 00000000..295cb018
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/logs.json
@@ -0,0 +1,15 @@
+{
+  "title": "日志",
+  "description": "实时日志流",
+  "descriptionLive": "正在实时追踪 {{level}} 级别",
+  "live": "实时",
+  "start": "开始",
+  "stop": "停止",
+  "clear": "清除",
+  "filterPlaceholder": "过滤日志...",
+  "logLevelTitle": "日志级别",
+  "emptyWaiting": "等待日志...",
+  "emptyFilter": "没有匹配的日志。",
+  "emptyStart": "点击「开始」以开始流式传输日志。",
+  "count": "{{filtered}}/{{total}}"
+}
diff --git a/ui/web/src/i18n/locales/zh/mcp.json b/ui/web/src/i18n/locales/zh/mcp.json
new file mode 100644
index 00000000..f4b8d976
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/mcp.json
@@ -0,0 +1,99 @@
+{
+  "title": "MCP 服务器",
+  "description": "管理 Model Context Protocol 服务器连接",
+  "addServer": "添加服务器",
+  "searchPlaceholder": "搜索服务器...",
+  "emptyTitle": "暂无 MCP 服务器",
+  "emptyDescription": "添加您的第一个 MCP 服务器以开始使用。",
+  "noMatchTitle": "未找到匹配服务器",
+  "noMatchDescription": "请尝试其他搜索词。",
+  "columns": {
+    "name": "名称",
+    "transport": "传输协议",
+    "tools": "工具",
+    "enabled": "已启用",
+    "createdBy": "创建者",
+    "actions": "操作"
+  },
+  "viewTools": "查看工具",
+  "manageGrants": "管理授权",
+  "delete": {
+    "title": "删除 MCP 服务器",
+    "description": "确定要删除「{{name}}」吗？这将同时移除所有相关授权。",
+    "confirmLabel": "删除"
+  },
+  "form": {
+    "createTitle": "添加 MCP 服务器",
+    "editTitle": "编辑 MCP 服务器",
+    "name": "名称 *",
+    "nameHint": "仅小写字母、数字和连字符",
+    "displayName": "显示名称",
+    "transport": "传输协议 *",
+    "command": "命令 *",
+    "args": "参数（逗号分隔）",
+    "argsPlaceholder": "--flag1, --flag2",
+    "url": "URL *",
+    "headers": "请求头",
+    "headerKeyPlaceholder": "请求头名称",
+    "headerValuePlaceholder": "请求头值",
+    "addHeader": "添加请求头",
+    "env": "环境变量",
+    "envKeyPlaceholder": "变量名称",
+    "envValuePlaceholder": "值",
+    "addVariable": "添加变量",
+    "toolPrefix": "工具前缀",
+    "toolPrefixHint": "如为空则自动从名称派生。",
+    "timeout": "超时（秒）",
+    "enabled": "已启用",
+    "testConnection": "测试连接",
+    "testing": "测试中...",
+    "toolsFound": "发现 {{count}} 个工具",
+    "cancel": "取消",
+    "create": "创建",
+    "update": "更新",
+    "saving": "保存中...",
+    "errors": {
+      "nameRequired": "名称和传输协议为必填项",
+      "nameSlug": "名称必须是有效的 slug（小写字母、数字、连字符）",
+      "commandRequired": "stdio 传输协议需要提供命令",
+      "urlRequired": "SSE/HTTP 传输协议需要提供 URL",
+      "connectionFailed": "连接失败"
+    }
+  },
+  "grants": {
+    "title": "Agent授权 - {{name}}",
+    "currentGrants": "当前授权",
+    "allToolsAllowed": "允许所有工具",
+    "addGrant": "添加Agent授权",
+    "editGrant": "编辑授权",
+    "selectAgent": "选择Agent...",
+    "toolAllowList": "工具允许列表（可选）",
+    "toolDenyList": "工具拒绝列表（可选）",
+    "allowPlaceholder": "选择要允许的工具...",
+    "denyPlaceholder": "选择要拒绝的工具...",
+    "grant": "授权",
+    "update": "更新",
+    "cancel": "取消",
+    "agentRequired": "Agent为必填项",
+    "failedGrant": "授权失败",
+    "failedRevoke": "撤销失败"
+  },
+  "tools": {
+    "title": "工具 — {{name}}",
+    "prefix": "前缀：",
+    "discovering": "正在发现工具...",
+    "noToolsTitle": "未发现工具",
+    "noToolsDescription": "服务器可能离线或没有注册任何工具。",
+    "failedLoad": "加载工具失败",
+    "filterPlaceholder": "过滤工具...",
+    "noMatch": "无匹配工具"
+  },
+  "toast": {
+    "created": "MCP 服务器已创建",
+    "updated": "MCP 服务器已更新",
+    "deleted": "MCP 服务器已删除",
+    "failedCreate": "创建 MCP 服务器失败",
+    "failedUpdate": "更新 MCP 服务器失败",
+    "failedDelete": "删除 MCP 服务器失败"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/memory.json b/ui/web/src/i18n/locales/zh/memory.json
new file mode 100644
index 00000000..21db1aa8
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/memory.json
@@ -0,0 +1,166 @@
+{
+  "title": "记忆",
+  "description": "浏览和管理Agent记忆文档、分块和嵌入",
+  "search": "搜索",
+  "create": "创建",
+  "indexAll": "全部索引",
+  "indexing": "索引中...",
+  "emptyTitle": "暂无记忆文档",
+  "emptyAgentDescription": "该Agent暂无记忆文档。",
+  "emptyGlobalDescription": "任何Agent均无记忆文档。",
+  "filters": {
+    "agent": "Agent",
+    "allAgents": "所有Agent",
+    "scope": "范围",
+    "allScope": "全部（全局 + 个人）"
+  },
+  "tabs": {
+    "documents": "文档",
+    "knowledgeGraph": "知识图谱"
+  },
+  "columns": {
+    "path": "路径",
+    "agent": "Agent",
+    "scope": "范围",
+    "hash": "哈希值",
+    "updated": "更新时间",
+    "actions": "操作"
+  },
+  "scopeLabel": {
+    "personal": "个人",
+    "global": "全局"
+  },
+  "delete": {
+    "title": "删除记忆文档",
+    "description": "确定要删除「{{path}}」吗？这将同时删除所有关联的分块和嵌入。",
+    "confirmLabel": "删除"
+  },
+  "createDialog": {
+    "title": "创建记忆文档",
+    "path": "路径 *",
+    "pathPlaceholder": "例如 notes/project-overview.md",
+    "content": "内容 *",
+    "contentPlaceholder": "文档内容...",
+    "agentId": "Agent *",
+    "agentIdPlaceholder": "选择Agent...",
+    "scope": "范围",
+    "existingScope": "现有范围",
+    "customScope": "自定义",
+    "selectGroupUser": "选择群组/用户...",
+    "scopeHint": "全局 = 与所有用户共享。个人 = 限定于特定用户或群组对话。",
+    "autoIndex": "创建后自动索引",
+    "agentRequired": "请选择Agent",
+    "pathRequired": "路径不能为空",
+    "contentRequired": "内容不能为空",
+    "cancel": "取消",
+    "create": "创建",
+    "creating": "创建中..."
+  },
+  "documentDialog": {
+    "title": "记忆文档",
+    "path": "路径：",
+    "agent": "Agent：",
+    "scope": "范围：",
+    "hash": "哈希值：",
+    "updated": "更新时间：",
+    "content": "内容",
+    "chunks": "分块（{{count}}）",
+    "chunkIndex": "分块 {{index}}",
+    "noChunks": "无分块",
+    "embedded": "已嵌入",
+    "noEmbedding": "未嵌入"
+  },
+  "searchDialog": {
+    "title": "搜索记忆",
+    "query": "搜索查询",
+    "queryPlaceholder": "输入搜索查询...",
+    "agentId": "Agent ID",
+    "agentIdPlaceholder": "按Agent筛选...",
+    "limit": "限制",
+    "search": "搜索",
+    "searching": "搜索中...",
+    "results": "结果",
+    "noResults": "未找到结果",
+    "similarity": "相似度",
+    "path": "路径："
+  },
+  "kg": {
+    "emptyTitle": "暂无实体",
+    "emptyDescription": "该Agent暂无知识图谱实体。",
+    "emptySearchDescription": "没有与您搜索匹配的实体。",
+    "stats": {
+      "entities": "实体：{{count}}",
+      "relations": "关系：{{count}}"
+    },
+    "search": {
+      "placeholder": "搜索实体...",
+      "button": "搜索",
+      "clear": "清除"
+    },
+    "refresh": "刷新",
+    "extract": "提取",
+    "columns": {
+      "name": "名称",
+      "type": "类型",
+      "description": "描述",
+      "confidence": "置信度",
+      "actions": "操作",
+      "observations": "观察",
+      "relations": "关系"
+    },
+    "deleteEntity": {
+      "title": "删除实体",
+      "description": "删除「{{name}}」？这将同时移除所有关联关系。",
+      "confirmLabel": "删除"
+    },
+    "entity": {
+      "externalId": "外部 ID：",
+      "confidence": "置信度：",
+      "description": "描述：",
+      "source": "来源：",
+      "properties": "属性：",
+      "relations": "关系",
+      "traverse": "遍历（2 跳）",
+      "traversing": "遍历中...",
+      "loading": "加载中...",
+      "noRelations": "未找到关系。",
+      "traversalResults": "遍历结果（{{count}}）",
+      "direction": {
+        "outgoing": "→ 出向",
+        "incoming": "← 入向"
+      },
+      "columns": {
+        "direction": "方向",
+        "relation": "关系",
+        "target": "目标",
+        "confidence": "置信度"
+      }
+    },
+    "extractDialog": {
+      "title": "从文本中提取实体",
+      "providerLabel": "提取Provider",
+      "modelLabel": "提取模型",
+      "textLabel": "待提取文本",
+      "textPlaceholder": "粘贴对话文本、笔记或任何内容以提取实体和关系...",
+      "extract": "提取",
+      "extracting": "提取中...",
+      "cancel": "取消",
+      "agentId": "Agent ID",
+      "agentIdPlaceholder": "留空为全局"
+    },
+    "graphView": {
+      "loading": "正在加载图谱...",
+      "empty": "没有可视化的实体",
+      "nodes": "{{count}} 个节点",
+      "edges": "{{count}} 条边"
+    }
+  },
+  "toast": {
+    "created": "记忆文档已创建",
+    "deleted": "记忆文档已删除",
+    "indexed": "所有文档已索引",
+    "failedCreate": "创建文档失败",
+    "failedDelete": "删除文档失败",
+    "failedIndex": "索引文档失败"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/nodes.json b/ui/web/src/i18n/locales/zh/nodes.json
new file mode 100644
index 00000000..c9b5f68f
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/nodes.json
@@ -0,0 +1,35 @@
+{
+  "title": "节点",
+  "description": "管理已配对设备和待处理配对请求",
+  "emptyTitle": "没有设备",
+  "emptyDescription": "没有已配对设备或待处理配对请求。",
+  "pendingRequests": "待处理请求 ({{count}})",
+  "pairedDevices": "已配对设备 ({{count}})",
+  "sender": "发送者：",
+  "chat": "聊天：",
+  "columns": {
+    "channel": "Channel",
+    "senderId": "发送者 ID",
+    "paired": "配对时间",
+    "by": "操作人",
+    "actions": "操作"
+  },
+  "approve": "批准",
+  "deny": "拒绝",
+  "revoke": "撤销",
+  "confirmApprove": {
+    "title": "批准配对",
+    "description": "批准来自 {{channel}}:{{senderId}} 的配对请求（代码：{{code}}）？该设备将能与Agent交互。",
+    "confirmLabel": "批准"
+  },
+  "confirmDeny": {
+    "title": "拒绝配对",
+    "description": "拒绝来自 {{channel}}:{{senderId}} 的配对请求（代码：{{code}}）？该请求将被移除。",
+    "confirmLabel": "拒绝"
+  },
+  "confirmRevoke": {
+    "title": "撤销设备",
+    "description": "撤销 {{channel}}:{{senderId}} 的配对？该设备将需要重新配对。",
+    "confirmLabel": "撤销"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/overview.json b/ui/web/src/i18n/locales/zh/overview.json
new file mode 100644
index 00000000..153dc8ba
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/overview.json
@@ -0,0 +1,74 @@
+{
+  "connectedClients": {
+    "columns": {
+      "connected": "连接时间",
+      "ip": "IP",
+      "role": "角色",
+      "user": "用户"
+    },
+    "noClients": "暂无已连接客户端",
+    "title": "已连接客户端",
+    "you": "（你）"
+  },
+  "cronJobs": {
+    "disabled": "已禁用",
+    "manage": "管理",
+    "noJobs": "暂无 Cron 任务",
+    "title": "Cron 任务"
+  },
+  "description": "网关概览和配额使用情况",
+  "providers": {
+    "goToSettings": "前往 Provider 设置",
+    "noEnabledDesc": "所有 Provider 均已禁用。请至少启用一个以开始使用 Agent。",
+    "noEnabledTitle": "未启用任何 LLM Provider",
+    "noProvidersDesc": "您需要添加至少一个 LLM Provider 才能让 Agent 工作。",
+    "noProvidersTitle": "未配置任何 LLM Provider"
+  },
+  "quotaUsage": {
+    "columns": {
+      "day": "日",
+      "hour": "时",
+      "userGroup": "用户 / 组",
+      "week": "周"
+    },
+    "noLimit": "无限制",
+    "title": "配额使用"
+  },
+  "recentRequests": {
+    "columns": {
+      "channel": "Channel",
+      "duration": "耗时",
+      "name": "名称",
+      "status": "状态",
+      "time": "时间",
+      "tokens": "Token",
+      "user": "用户"
+    },
+    "noRequests": "暂无最近请求",
+    "title": "最近请求",
+    "viewAll": "查看全部"
+  },
+  "statCards": {
+    "agents": "Agent",
+    "channels": "Channel",
+    "inOut": "输入 / 输出",
+    "online": "在线",
+    "requestsToday": "今日请求",
+    "running": "运行中",
+    "tokensToday": "今日 Token",
+    "users": "用户"
+  },
+  "systemHealth": {
+    "active": "活跃",
+    "channels": "Channel",
+    "clients": "客户端",
+    "database": "数据库",
+    "none": "无",
+    "providers": "Provider",
+    "sessions": "Session",
+    "title": "系统健康",
+    "tools": "工具",
+    "uptime": "运行时间"
+  },
+  "title": "概览"
+}
diff --git a/ui/web/src/i18n/locales/zh/pending-messages.json b/ui/web/src/i18n/locales/zh/pending-messages.json
new file mode 100644
index 00000000..0e427748
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/pending-messages.json
@@ -0,0 +1,31 @@
+{
+  "title": "待处理消息",
+  "description": "已缓冲的Channel消息，等待Agent处理",
+  "emptyTitle": "暂无待处理消息",
+  "emptyDescription": "未找到缓冲消息组。当Channel在Agent处理前缓冲传入消息时，消息将显示在此处。",
+  "columns": {
+    "channel": "Channel",
+    "group": "组",
+    "messages": "消息",
+    "status": "状态",
+    "lastActivity": "最近活动",
+    "actions": "操作"
+  },
+  "status": {
+    "compacted": "已压缩",
+    "raw": "原始"
+  },
+  "compact": "压缩",
+  "clear": "清除",
+  "confirmClear": {
+    "title": "清除消息？",
+    "description": "这将永久删除 {{channel}} / {{key}} 中的所有消息。此操作无法撤销。",
+    "cancel": "取消",
+    "confirm": "清除"
+  },
+  "dialog": {
+    "title": "消息 — {{name}}",
+    "noMessages": "未找到消息。",
+    "summary": "摘要"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/providers.json b/ui/web/src/i18n/locales/zh/providers.json
new file mode 100644
index 00000000..01a48e6b
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/providers.json
@@ -0,0 +1,115 @@
+{
+  "title": "Provider",
+  "description": "管理 LLM Provider",
+  "addProvider": "添加Provider",
+  "searchPlaceholder": "搜索Provider...",
+  "emptyTitle": "暂无Provider",
+  "emptyDescription": "添加您的第一个 LLM Provider以开始使用。",
+  "noMatchTitle": "未找到匹配Provider",
+  "noMatchDescription": "请尝试其他搜索词。",
+  "columns": {
+    "name": "名称",
+    "type": "类型",
+    "apiBase": "API 基础地址",
+    "apiKey": "API 密钥",
+    "status": "状态",
+    "actions": "操作"
+  },
+  "apiKey": {
+    "oauthToken": "OAuth 令牌",
+    "notSet": "未设置"
+  },
+  "form": {
+    "createTitle": "添加Provider",
+    "editTitle": "编辑Provider",
+    "name": "名称 *",
+    "namePlaceholder": "例如 openrouter",
+    "nameHint": "小写字母、数字、连字符",
+    "displayName": "显示名称",
+    "displayNamePlaceholder": "OpenRouter",
+    "providerType": "Provider类型 *",
+    "apiKey": "API 密钥",
+    "apiKeyPlaceholder": "sk-...",
+    "apiKeyEditPlaceholder": "保持不变或输入新密钥",
+    "apiKeySetHint": "API 密钥已设置。清除并输入新值以更改。",
+    "apiBase": "API 基础 URL",
+    "enabled": "已启用",
+    "cancel": "取消",
+    "close": "关闭",
+    "create": "创建",
+    "save": "保存",
+    "update": "更新",
+    "saving": "保存中...",
+    "creating": "创建中...",
+    "alreadyAdded": "（已添加）",
+    "nameFixed": "名称",
+    "configure": "配置 LLM Provider连接。",
+    "lowercaseHint": "小写字母、数字、连字符"
+  },
+  "delete": {
+    "title": "删除Provider",
+    "description": "确定要删除「{{name}}」吗？此操作无法撤销。",
+    "confirmLabel": "删除"
+  },
+  "types": {
+    "anthropic_native": "Anthropic",
+    "openai_compat": "OpenAI Compat",
+    "gemini_native": "Gemini",
+    "openrouter": "OpenRouter",
+    "groq": "Groq",
+    "deepseek": "DeepSeek",
+    "mistral": "Mistral",
+    "xai": "xAI",
+    "minimax_native": "MiniMax",
+    "cohere": "Cohere",
+    "perplexity": "Perplexity",
+    "chatgpt_oauth": "ChatGPT (OAuth)",
+    "yescale": "YesScale"
+  },
+  "oauth": {
+    "checkingStatus": "正在检查认证状态...",
+    "authSuccessful": "认证成功！",
+    "activeProvider": "Provider",
+    "closingIn": "现已激活。{{count}} 秒后关闭...",
+    "authenticated": "已认证 — Provider",
+    "active": "活跃",
+    "modelPrefixHint": "在Agent配置中使用模型前缀",
+    "modelPrefixExample": "（例如 openai-codex/gpt-4o）。令牌自动刷新。",
+    "removeToken": "移除令牌",
+    "signInDesc": "使用您的 ChatGPT 账户登录，无需单独的 API 密钥即可使用订阅中的模型。",
+    "waiting": "等待认证中... 请在已打开的窗口中完成登录。",
+    "remoteVpsHint": "登录后，您的浏览器将尝试打开",
+    "remoteVpsError": "并显示「无法访问此页面」错误。这是正常的 — 从浏览器地址栏复制完整 URL 并粘贴到下方。",
+    "pasteUrlPlaceholder": "http://localhost:1455/auth/callback?code=...&state=...",
+    "submit": "提交",
+    "signInWithChatGPT": "使用 ChatGPT 登录",
+    "starting": "启动中...",
+    "remoteVps": "远程/VPS?",
+    "loggedOut": "已登出",
+    "loggedOutDesc": "OpenAI OAuth 令牌已移除",
+    "oauthFailed": "OAuth 失败",
+    "exchangeFailed": "交换失败"
+  },
+  "cli": {
+    "description": "Claude CLI 使用本地",
+    "descriptionSuffix": "二进制文件。无需 API 密钥。",
+    "checkingAuth": "正在检查认证...",
+    "authenticatedAs": "已认证为",
+    "switchAccount": "切换账户？",
+    "switchAccountInstructions": "在服务器终端运行：",
+    "switchAccountRecheck": "然后点击",
+    "switchAccountRecheckSuffix": "重新检查。",
+    "notAuthenticated": "未认证",
+    "runOnServer": "在服务器终端运行：",
+    "recheckButton": "重新检查"
+  },
+  "toast": {
+    "created": "Provider已创建",
+    "createdDesc": "{{name}} 已添加",
+    "updated": "Provider已更新",
+    "deleted": "Provider已删除",
+    "failedCreate": "创建Provider失败",
+    "failedUpdate": "更新Provider失败",
+    "failedDelete": "删除Provider失败"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/sessions.json b/ui/web/src/i18n/locales/zh/sessions.json
new file mode 100644
index 00000000..d0b3476d
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/sessions.json
@@ -0,0 +1,34 @@
+{
+  "title": "Session",
+  "description": "浏览对话Session",
+  "searchPlaceholder": "搜索Session...",
+  "emptyTitle": "暂无Session",
+  "emptyDescription": "开始聊天后Session将显示在此处。",
+  "noMatchTitle": "未找到匹配的Session",
+  "noMatchDescription": "请尝试其他搜索词。",
+  "columns": {
+    "session": "Session",
+    "agent": "Agent",
+    "channel": "Channel",
+    "messages": "消息",
+    "updated": "更新时间"
+  },
+  "detail": {
+    "reset": "重置",
+    "delete": "删除",
+    "deleteTitle": "删除Session",
+    "deleteDescription": "这将永久删除此Session中的所有消息。",
+    "resetTitle": "重置Session",
+    "resetDescription": "这将清除所有消息但保留Session。",
+    "confirmDelete": "删除",
+    "confirmReset": "重置",
+    "noMessages": "此Session中没有消息",
+    "summary": "摘要",
+    "showMore": "显示更多",
+    "showLess": "收起",
+    "showDetails": "显示详情",
+    "hide": "隐藏",
+    "systemMessage": "系统消息",
+    "messages": "条消息"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/setup.json b/ui/web/src/i18n/locales/zh/setup.json
new file mode 100644
index 00000000..3a8c24db
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/setup.json
@@ -0,0 +1,102 @@
+{
+  "layout": {
+    "subtitle": "让我们来配置您的网关"
+  },
+  "steps": {
+    "provider": "Provider",
+    "model": "模型",
+    "agent": "Agent",
+    "channel": "Channel",
+    "channelOptional": "（可选）"
+  },
+  "complete": {
+    "title": "设置完成！",
+    "ready": "系统已准备就绪！",
+    "description": "Provider、Agent和Channel已配置完成。您可以随时从控制台管理它们。",
+    "goToDashboard": "前往控制台"
+  },
+  "provider": {
+    "title": "配置 LLM Provider",
+    "descriptionCli": "使用本地 Claude CLI 连接，无需 API 密钥。",
+    "description": "连接 AI Provider为您的Agent提供支持，需要 API 密钥。",
+    "providerType": "Provider类型",
+    "providerTypeHint": "您要连接的 LLM 服务。推荐使用 OpenRouter 以访问多种模型。",
+    "name": "名称",
+    "nameHint": "此Provider的内部标识符，根据Provider类型自动生成。",
+    "apiKey": "API 密钥 *",
+    "apiKeyHint": "您的Provider密钥，服务端加密存储，不会在 API 响应中暴露。",
+    "apiBase": "API 基础 URL",
+    "apiBaseHint": "API 请求的端点 URL，根据Provider类型自动填充，仅在使用自定义代理时覆盖。",
+    "creating": "创建中...",
+    "create": "创建Provider",
+    "errors": {
+      "apiKeyRequired": "API 密钥为必填项",
+      "failedCreate": "创建Provider失败"
+    }
+  },
+  "model": {
+    "title": "选择并验证模型",
+    "description": "选择模型并验证Provider连接是否正常。",
+    "provider": "Provider：",
+    "model": "模型 *",
+    "modelHint": "要使用的 AI 模型，从列表中选择或手动输入模型 ID。",
+    "loadingModels": "正在加载模型...",
+    "selectModel": "选择或输入模型 ID",
+    "noModelsHint": "此Provider不列出模型 — 请手动输入模型 ID。",
+    "verified": "已验证",
+    "verify": "验证",
+    "verifying": "验证中...",
+    "continue": "继续",
+    "modelVerified": "模型已验证",
+    "modelVerifiedDesc": "{{model}} 运行正常",
+    "verificationFailed": "验证失败，请检查您的 API 密钥和模型。"
+  },
+  "agent": {
+    "title": "创建您的第一个Agent",
+    "description": "Agent是您的 AI 助手，自定义其名称和个性。",
+    "provider": "Provider：",
+    "model": "模型：",
+    "displayName": "显示名称",
+    "displayNameHint": "将在召唤过程中根据Agent个性自动生成。",
+    "agentKey": "Agent标识",
+    "agentKeyHint": "Agent的唯一标识符，仅限小写字母、数字和连字符。",
+    "agentKeyPlaceholder": "my-agent",
+    "personality": "Agent个性",
+    "personalityHint": "描述Agent的角色和行为，召唤时 AI 将从此生成上下文文件。",
+    "personalityPlaceholder": "描述Agent的个性、用途和行为...",
+    "personalityHintBottom": "自定义此提示词以塑造Agent的个性和专业领域。",
+    "selfEvolve": "自我进化",
+    "selfEvolveDesc": "允许Agent通过 SOUL.md 随时间进化其沟通风格",
+    "creating": "创建中...",
+    "create": "创建Agent",
+    "summoningFailed": "召唤失败，请调整设置后重试。",
+    "errors": {
+      "noProvider": "没有可用的Provider",
+      "failedCreate": "创建Agent失败"
+    }
+  },
+  "channel": {
+    "title": "连接Channel",
+    "description": "将消息平台连接到您的Agent，您可以稍后添加Channel。",
+    "skip": "跳过",
+    "skipFinish": "跳过并完成",
+    "agent": "Agent：",
+    "channelType": "Channel类型",
+    "channelTypeHint": "要连接的消息平台，例如 Telegram、Discord、Zalo。",
+    "name": "名称",
+    "nameHint": "此Channel实例的内部标识符，根据Channel类型自动生成。",
+    "namePlaceholder": "my-telegram",
+    "displayName": "显示名称",
+    "displayNameHint": "在界面中显示的友好名称，可选。",
+    "displayNamePlaceholder": "销售机器人",
+    "credentials": "凭证",
+    "credentialsHint": "服务端加密存储，不会在 API 响应中返回。",
+    "creating": "创建中...",
+    "create": "创建Channel",
+    "errors": {
+      "noAgent": "没有可用的Agent",
+      "requiredFields": "必填项：{{fields}}",
+      "failedCreate": "创建Channel失败"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/sidebar.json b/ui/web/src/i18n/locales/zh/sidebar.json
new file mode 100644
index 00000000..346341bd
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/sidebar.json
@@ -0,0 +1,34 @@
+{
+  "groups": {
+    "core": "核心",
+    "management": "管理",
+    "monitoring": "监控",
+    "system": "系统"
+  },
+  "nav": {
+    "agentTeams": "Agent Team",
+    "agents": "Agent",
+    "approvals": "审批",
+    "builtinTools": "内置工具",
+    "channels": "Channel",
+    "chat": "对话",
+    "config": "配置",
+    "cron": "定时任务",
+    "customTools": "自定义工具",
+    "delegations": "委托",
+    "logs": "日志",
+    "mcpServers": "MCP 服务器",
+    "memory": "记忆",
+    "nodes": "节点",
+    "overview": "概览",
+    "pendingMessages": "待处理消息",
+    "providers": "Provider",
+    "realtimeEvents": "实时事件",
+    "sessions": "Session",
+    "skills": "Skill",
+    "storage": "存储",
+    "traces": "追踪",
+    "tts": "语音合成",
+    "usage": "用量"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/skills.json b/ui/web/src/i18n/locales/zh/skills.json
new file mode 100644
index 00000000..97c518a1
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/skills.json
@@ -0,0 +1,55 @@
+{
+  "title": "Skill",
+  "description": "管理AgentSkill和能力",
+  "searchPlaceholder": "搜索Skill...",
+  "emptyTitle": "暂无Skill",
+  "emptyDescription": "尚未注册任何Skill。",
+  "noMatchTitle": "未找到匹配的Skill",
+  "noMatchDescription": "请尝试其他搜索词。",
+  "columns": {
+    "name": "名称",
+    "description": "描述",
+    "source": "来源",
+    "visibility": "可见性",
+    "actions": "操作"
+  },
+  "noDescription": "暂无描述",
+  "delete": {
+    "title": "删除Skill",
+    "description": "确定要删除「{{name}}」吗？此操作无法撤销。",
+    "confirmLabel": "删除"
+  },
+  "upload": {
+    "title": "上传Skill",
+    "description": "上传包含带 YAML frontmatter (name, description, slug) 的 SKILL.md 的 ZIP 文件。",
+    "button": "上传",
+    "uploading": "上传中...",
+    "dropOrClick": "点击或拖放 .zip 文件",
+    "dropHere": "将 .zip 文件拖放到此处",
+    "onlyZip": "只接受 .zip 文件",
+    "cancel": "取消"
+  },
+  "edit": {
+    "title": "编辑Skill",
+    "name": "名称",
+    "description": "描述",
+    "visibility": "可见性",
+    "tags": "标签",
+    "addTag": "添加标签...",
+    "add": "添加",
+    "cancel": "取消",
+    "save": "保存",
+    "saving": "保存中...",
+    "privateOption": "私有（仅所有者）",
+    "internalOption": "内部（已授权的Agent/用户）",
+    "publicOption": "公开（所有Agent）"
+  },
+  "detail": {
+    "title": "Skill详情",
+    "content": "内容",
+    "files": "文件",
+    "version": "版本：",
+    "current": "（当前）",
+    "noContent": "无可用内容。"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/storage.json b/ui/web/src/i18n/locales/zh/storage.json
new file mode 100644
index 00000000..5d83f8d1
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/storage.json
@@ -0,0 +1,14 @@
+{
+  "title": "存储",
+  "description": "工作区文件浏览器",
+  "descriptionWithPath": "{{path}} — {{size}}",
+  "delete": {
+    "fileTitle": "删除文件",
+    "folderTitle": "删除文件夹",
+    "description": "确定要删除 {{name}} 吗？",
+    "folderWarning": " 所有内容将被递归删除。",
+    "undone": " 此操作不可撤销。",
+    "deleting": "删除中...",
+    "confirmLabel": "删除"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/teams.json b/ui/web/src/i18n/locales/zh/teams.json
new file mode 100644
index 00000000..b0d3ae37
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/teams.json
@@ -0,0 +1,150 @@
+{
+  "title": "Agent Team",
+  "description": "管理您的Agent Team",
+  "createTeam": "创建Team",
+  "searchPlaceholder": "搜索Team...",
+  "emptyTitle": "暂无Team",
+  "emptyDescription": "创建您的第一个Team以开始使用。",
+  "noMatchTitle": "未找到匹配Team",
+  "noMatchDescription": "请尝试其他搜索词。",
+  "delete": {
+    "title": "删除Team",
+    "description": "确定要删除「{{name}}」吗？此操作无法撤销。",
+    "confirmLabel": "删除"
+  },
+  "detail": {
+    "lead": "负责人",
+    "memberCount": "{{count}} 位成员",
+    "memberCountPlural": "{{count}} 位成员",
+    "deleteDescription": "确定要删除「{{name}}」吗？所有成员、任务和配置将被永久移除。",
+    "tabs": {
+      "tasks": "任务",
+      "members": "成员",
+      "delegations": "委托",
+      "settings": "设置"
+    }
+  },
+  "members": {
+    "title": "成员",
+    "noMembers": "暂无成员",
+    "addMember": "添加成员",
+    "addMemberTooltip": "只有预定义Agent才能作为Team成员添加。开放Agent是按用户划分的，缺乏Team协作所需的共享上下文。",
+    "selectAgent": "选择要添加的Agent...",
+    "noAvailableAgents": "无可用Agent",
+    "searchAgents": "搜索Agent...",
+    "adding": "添加中...",
+    "add": "添加",
+    "removeMember": "移除成员",
+    "columns": {
+      "agent": "Agent",
+      "frontmatter": "前置信息",
+      "role": "角色",
+      "addedAt": "添加时间",
+      "actions": "操作"
+    }
+  },
+  "tasks": {
+    "title": "任务",
+    "loading": "加载任务中...",
+    "noTasks": "暂无任务",
+    "noTasksDescription": "任务由TeamAgent在协作过程中创建。",
+    "refresh": "刷新",
+    "columns": {
+      "subject": "主题",
+      "status": "状态",
+      "owner": "负责人",
+      "priority": "优先级",
+      "taskId": "任务 ID",
+      "created": "创建时间",
+      "actions": "操作"
+    },
+    "detail": {
+      "title": "任务详情",
+      "subject": "主题",
+      "status": "状态：",
+      "priority": "优先级：",
+      "owner": "负责人：",
+      "blockedBy": "被阻塞：",
+      "description": "描述",
+      "result": "结果",
+      "created": "创建时间：",
+      "updated": "更新时间：",
+      "taskId": "任务 ID：",
+      "noDescription": "无描述",
+      "noResult": "暂无结果"
+    }
+  },
+  "delegations": {
+    "noTitle": "暂无委托",
+    "noDescription": "未找到该Team的委托记录。",
+    "refresh": "刷新",
+    "columns": {
+      "sourceTarget": "来源 / 目标",
+      "task": "任务",
+      "status": "状态",
+      "duration": "耗时",
+      "time": "时间"
+    }
+  },
+  "settings": {
+    "title": "Team设置",
+    "name": "名称",
+    "displayName": "显示名称",
+    "description": "描述",
+    "leadAgent": "负责Agent",
+    "status": "状态",
+    "active": "活跃",
+    "inactive": "非活跃",
+    "save": "保存设置",
+    "saving": "保存中...",
+    "saved": "已保存",
+    "failedSave": "保存失败",
+    "userAccessControl": "用户访问控制",
+    "allowedUsers": "允许的用户",
+    "allowedUsersHint": "若已设置，仅这些用户可触发Team工作流。留空 = 所有人均可。",
+    "deniedUsers": "拒绝的用户",
+    "deniedUsersHint": "始终被阻止，覆盖允许列表。",
+    "channelRestrictions": "Channel限制",
+    "allowedChannels": "允许的Channel",
+    "allowedChannelsHint": "若已设置，仅这些Channel可激活Team工作流。留空 = 所有Channel均可。",
+    "deniedChannels": "拒绝的Channel",
+    "deniedChannelsHint": "来自这些Channel的消息始终被阻止。",
+    "notifications": "通知",
+    "progressNotifications": "进度通知",
+    "progressNotificationsHint": "在异步委托期间，定期向对话发送「您的Team正在处理中...」消息。",
+    "searchUsers": "搜索用户...",
+    "selectChannel": "选择Channel..."
+  },
+  "create": {
+    "title": "创建Team",
+    "name": "名称 *",
+    "namePlaceholder": "例如 研究Team",
+    "nameHint": "小写字母、数字、连字符",
+    "description": "描述",
+    "descriptionPlaceholder": "可选的Team描述...",
+    "leadAgent": "负责Agent *",
+    "selectLeadAgent": "选择负责Agent...",
+    "loadingAgents": "加载Agent中...",
+    "noActiveAgents": "未找到活跃Agent，请先创建Agent。",
+    "members": "成员",
+    "membersTooltip": "只有预定义Agent才能作为Team成员添加。开放Agent是按用户划分的，缺乏Team协作所需的共享上下文。",
+    "searchMembers": "搜索并添加成员...",
+    "displayName": "显示名称",
+    "displayNamePlaceholder": "支持Team",
+    "cancel": "取消",
+    "create": "创建",
+    "creating": "创建中..."
+  },
+  "toast": {
+    "created": "Team已创建",
+    "deleted": "Team已删除",
+    "updated": "Team已更新",
+    "memberAdded": "成员已添加",
+    "memberRemoved": "成员已移除",
+    "failedCreate": "创建Team失败",
+    "failedDelete": "删除Team失败",
+    "failedUpdate": "更新Team失败",
+    "failedAddMember": "添加成员失败",
+    "failedRemoveMember": "移除成员失败"
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/tools.json b/ui/web/src/i18n/locales/zh/tools.json
new file mode 100644
index 00000000..a5bad50a
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/tools.json
@@ -0,0 +1,156 @@
+{
+  "builtin": {
+    "categories": {
+      "browser": "浏览器",
+      "delegation": "委托",
+      "filesystem": "文件系统",
+      "media": "媒体",
+      "memory": "内存",
+      "messaging": "消息",
+      "runtime": "运行时",
+      "scheduling": "调度",
+      "sessions": "Session",
+      "skills": "Skill",
+      "subagents": "Agent",
+      "teams": "Team",
+      "web": "网页"
+    },
+    "categoryCount": "{{count}} 个分类",
+    "configuredVia": "通过配置页面配置",
+    "description": "管理系统内置工具。全局启用/禁用或配置设置。",
+    "emptyDescription": "尚未初始化任何内置工具。",
+    "emptyTitle": "暂无内置工具",
+    "jsonDialog": {
+      "cancel": "取消",
+      "cannotFormat": "无法格式化：JSON 无效",
+      "description": "以 JSON 格式编辑工具专属设置。保存后立即生效。",
+      "formatJson": "格式化 JSON",
+      "invalidJson": "无效的 JSON",
+      "invalidJsonSyntax": "JSON 语法无效",
+      "save": "保存",
+      "saving": "保存中...",
+      "title": "设置：{{name}}"
+    },
+    "kgSettings": {
+      "autoExtract": "写入内存时自动提取",
+      "autoExtractHint": "当Agent写入内存文件时自动提取实体。",
+      "cancel": "取消",
+      "description": "配置从内存写入中提取实体。需要支持结构化 JSON 输出的Provider/模型。",
+      "extractionModel": "提取模型",
+      "extractionProvider": "提取Provider",
+      "minConfidence": "最低置信度",
+      "minConfidenceHint": "低于此置信度分数的实体将被丢弃（0.0–1.0）。",
+      "modelTip": "用于提取的模型 ID。应支持结构化 JSON 输出。",
+      "providerTip": "用于从文本中提取实体和关系的 LLM Provider。",
+      "save": "保存",
+      "saving": "保存中...",
+      "title": "知识图谱设置"
+    },
+    "mediaChain": {
+      "addProvider": "添加Provider",
+      "cancel": "取消",
+      "description": "配置并排序Provider回退。拖动以重新排序 — 第一个启用的Provider将被优先尝试。",
+      "loadingModels": "加载中...",
+      "model": "模型",
+      "newProvider": "新Provider",
+      "noProviders": "未配置Provider。请在下方添加。",
+      "provider": "Provider",
+      "providerChainSuffix": "— Provider链",
+      "retries": "重试次数",
+      "save": "保存",
+      "saving": "保存中...",
+      "selectModel": "选择模型",
+      "selectProvider": "选择Provider",
+      "settings": "设置",
+      "timeout": "超时"
+    },
+    "noMatchDescription": "请尝试其他搜索词。",
+    "noMatchTitle": "未找到匹配工具",
+    "requires": "需要",
+    "requiresTooltip": "需要：{{list}}",
+    "searchPlaceholder": "搜索工具...",
+    "settings": "设置",
+    "settingsDialog": {
+      "cancel": "取消",
+      "noFields": "此工具没有可配置的设置。",
+      "save": "保存",
+      "saving": "保存中...",
+      "title": "设置 — {{name}}",
+      "toast": {
+        "failed": "保存设置失败",
+        "saved": "设置已保存"
+      }
+    },
+    "title": "内置工具",
+    "toast": {
+      "failedToggle": "更新工具失败",
+      "toggled": "工具已更新"
+    },
+    "toolCount": "{{count}} 个工具",
+    "toolCountPlural": "{{count}} 个工具"
+  },
+  "custom": {
+    "columns": {
+      "actions": "操作",
+      "description": "描述",
+      "enabled": "已启用",
+      "name": "名称",
+      "scope": "范围",
+      "timeout": "超时"
+    },
+    "createTool": "创建工具",
+    "delete": {
+      "confirmLabel": "删除",
+      "description": "确定要删除「{{name}}」吗？此操作无法撤销。",
+      "title": "删除自定义工具"
+    },
+    "description": "管理Agent的自定义 Shell 工具",
+    "emptyDescription": "创建您的第一个自定义工具以开始使用。",
+    "emptyTitle": "暂无自定义工具",
+    "form": {
+      "agentId": "Agent ID（可选）",
+      "agentIdPlaceholder": "留空为全局范围",
+      "cancel": "取消",
+      "command": "命令 *",
+      "commandHint": "Shell 模板。使用 {{.key}} 作为参数占位符。",
+      "create": "创建",
+      "createTitle": "创建自定义工具",
+      "description": "描述",
+      "descriptionPlaceholder": "此工具的功能...",
+      "editTitle": "编辑工具",
+      "enabled": "已启用",
+      "errors": {
+        "invalidJson": "参数必须是有效的 JSON",
+        "nameRequired": "名称和命令为必填项",
+        "nameSlug": "名称必须是有效的 slug（小写字母、数字、连字符）"
+      },
+      "name": "名称 *",
+      "nameHint": "仅小写字母、数字和连字符",
+      "namePlaceholder": "my-tool",
+      "parameters": "参数（JSON Schema）",
+      "saving": "保存中...",
+      "timeout": "超时（秒）",
+      "update": "更新",
+      "workingDir": "工作目录",
+      "workingDirPlaceholder": "/path/to/dir"
+    },
+    "noDescription": "无描述",
+    "noMatchDescription": "请尝试其他搜索词。",
+    "noMatchTitle": "未找到匹配工具",
+    "scope": {
+      "agent": "Agent",
+      "global": "全局"
+    },
+    "searchPlaceholder": "搜索工具...",
+    "title": "自定义工具",
+    "toast": {
+      "created": "工具已创建",
+      "createdDesc": "{{name}} 已添加",
+      "deleted": "工具已删除",
+      "failedCreate": "创建工具失败",
+      "failedDelete": "删除工具失败",
+      "failedUpdate": "更新工具失败",
+      "updated": "工具已更新"
+    }
+  }
+}
diff --git a/ui/web/src/i18n/locales/zh/topbar.json b/ui/web/src/i18n/locales/zh/topbar.json
new file mode 100644
index 00000000..08706a45
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/topbar.json
@@ -0,0 +1,16 @@
+{
+  "collapseSidebar": "收起侧边栏",
+  "expandSidebar": "展开侧边栏",
+  "language": "语言",
+  "languages": {
+    "en": "English",
+    "vi": "Tiếng Việt",
+    "zh": "中文"
+  },
+  "logout": "退出登录",
+  "openMenu": "打开菜单",
+  "pairingRequests": "配对请求",
+  "pendingPairingRequest": "待处理配对请求",
+  "pendingPairingRequests": "{{count}} 个待处理配对请求",
+  "toggleTheme": "切换主题"
+}
diff --git a/ui/web/src/i18n/locales/zh/traces.json b/ui/web/src/i18n/locales/zh/traces.json
new file mode 100644
index 00000000..168a5f3d
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/traces.json
@@ -0,0 +1,49 @@
+{
+  "cached": "已缓存",
+  "columns": {
+    "duration": "耗时",
+    "name": "名称",
+    "spans": "跨度",
+    "status": "状态",
+    "time": "时间",
+    "tokens": "令牌"
+  },
+  "description": "LLM 调用追踪和性能数据",
+  "detail": {
+    "channel": "Channel：",
+    "copyTraceId": "复制追踪 ID",
+    "delegatedFrom": "委托来自：",
+    "duration": "耗时：",
+    "input": "输入",
+    "llmCalls": "LLM 调用",
+    "name": "名称：",
+    "notFound": "未找到追踪。",
+    "output": "输出",
+    "spans": "跨度：",
+    "spansCount": "跨度（{{count}}）",
+    "started": "开始时间：",
+    "status": "状态：",
+    "title": "追踪详情",
+    "tokens": "令牌：",
+    "toolCalls": "工具"
+  },
+  "emptyDescription": "暂无追踪记录。当Agent处理请求时将自动记录追踪。",
+  "emptyTitle": "暂无追踪",
+  "filter": "筛选",
+  "filterPlaceholder": "按Agent ID 筛选...",
+  "span": {
+    "cacheRead": "读取",
+    "cacheWrite": "写入",
+    "cached": "已缓存",
+    "input": "输入：",
+    "model": "模型：",
+    "output": "输出：",
+    "thinking": "思考",
+    "tokens": "令牌："
+  },
+  "title": "追踪",
+  "toast": {
+    "failedLoad": "加载追踪失败"
+  },
+  "unnamed": "未命名"
+}
diff --git a/ui/web/src/i18n/locales/zh/tts.json b/ui/web/src/i18n/locales/zh/tts.json
new file mode 100644
index 00000000..0e42d33b
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/tts.json
@@ -0,0 +1,71 @@
+{
+  "autoModes": {
+    "always": "始终",
+    "alwaysDesc": "所有回复均生成音频",
+    "inbound": "入站",
+    "inboundDesc": "仅当用户发送语音/音频时",
+    "off": "关闭",
+    "offDesc": "Agent可手动使用 TTS 工具",
+    "tagged": "标记",
+    "taggedDesc": "仅当回复包含 [[tts]] 标签时"
+  },
+  "description": "配置 TTS Provider和自动应用设置",
+  "edge": {
+    "hint": "Edge TTS 免费且无需 API Key。安装方式：pip install edge-tts",
+    "speechRate": "语速",
+    "voice": "语音"
+  },
+  "elevenlabs": {
+    "apiKey": "API Key",
+    "baseUrl": "Base URL",
+    "modelId": "Model ID",
+    "voiceId": "Voice ID"
+  },
+  "general": {
+    "autoApplyMode": "自动应用模式",
+    "maxTextLength": "最大文本长度",
+    "primaryProvider": "主要Provider",
+    "replyMode": "回复模式",
+    "timeout": "超时（毫秒）",
+    "title": "常规设置"
+  },
+  "minimax": {
+    "apiBase": "API Base",
+    "apiKey": "API Key",
+    "groupId": "Group ID",
+    "groupIdPlaceholder": "MiniMax 必填",
+    "model": "模型",
+    "voiceId": "Voice ID"
+  },
+  "openai": {
+    "apiBase": "API Base URL",
+    "apiKey": "API Key",
+    "model": "模型",
+    "voice": "语音"
+  },
+  "providerSettings": "{{provider}} 设置",
+  "providers": {
+    "edge": "Edge（免费）",
+    "elevenlabs": "ElevenLabs",
+    "minimax": "MiniMax",
+    "none": "无（已禁用）",
+    "openai": "OpenAI"
+  },
+  "replyModes": {
+    "all": "全部",
+    "allDesc": "包括工具/块在内的所有回复",
+    "final": "仅最终回复",
+    "finalDesc": "仅最终回复"
+  },
+  "save": "保存",
+  "saveChanges": "保存更改",
+  "saving": "保存中...",
+  "status": {
+    "activeProvider": "主要Provider：{{provider}}，自动：{{auto}}",
+    "configured": "已配置",
+    "disabled": "已禁用",
+    "noProvider": "未配置 TTS Provider",
+    "title": "状态"
+  },
+  "title": "语音合成"
+}
diff --git a/ui/web/src/i18n/locales/zh/usage.json b/ui/web/src/i18n/locales/zh/usage.json
new file mode 100644
index 00000000..9dbb66c2
--- /dev/null
+++ b/ui/web/src/i18n/locales/zh/usage.json
@@ -0,0 +1,21 @@
+{
+  "title": "用量",
+  "description": "按Agent统计令牌用量和费用",
+  "emptyTitle": "暂无用量数据",
+  "emptyDescription": "Agent处理请求后，用量数据将显示在此处。",
+  "recentRecords": "近期记录",
+  "summary": {
+    "sessions": "{{count}} 个Session",
+    "inputTokens": "输入令牌",
+    "outputTokens": "输出令牌",
+    "total": "合计"
+  },
+  "columns": {
+    "agent": "Agent",
+    "model": "模型",
+    "provider": "Provider",
+    "input": "输入",
+    "output": "输出",
+    "total": "合计"
+  }
+}
diff --git a/ui/web/src/lib/constants.ts b/ui/web/src/lib/constants.ts
index 40e9f575..6c4af913 100644
--- a/ui/web/src/lib/constants.ts
+++ b/ui/web/src/lib/constants.ts
@@ -41,4 +41,14 @@ export const LOCAL_STORAGE_KEYS = {
   SENDER_ID: "goclaw:senderID",
   THEME: "goclaw:theme",
   SIDEBAR_COLLAPSED: "goclaw:sidebarCollapsed",
+  LANGUAGE: "goclaw:language",
 } as const;
+
+export const SUPPORTED_LANGUAGES = ["en", "vi", "zh"] as const;
+export type Language = (typeof SUPPORTED_LANGUAGES)[number];
+
+export const LANGUAGE_LABELS: Record<Language, string> = {
+  en: "English",
+  vi: "Tiếng Việt",
+  zh: "中文",
+};
diff --git a/ui/web/src/main.tsx b/ui/web/src/main.tsx
index c2a145c6..5e7aa1ee 100644
--- a/ui/web/src/main.tsx
+++ b/ui/web/src/main.tsx
@@ -1,5 +1,6 @@
 import { StrictMode } from "react";
 import { createRoot } from "react-dom/client";
+import "./i18n";
 import App from "./App";
 import "./index.css";
 
diff --git a/ui/web/src/pages/agents/agent-card.tsx b/ui/web/src/pages/agents/agent-card.tsx
index 9e7a76f1..18151444 100644
--- a/ui/web/src/pages/agents/agent-card.tsx
+++ b/ui/web/src/pages/agents/agent-card.tsx
@@ -1,4 +1,5 @@
 import { Bot, Star, RotateCcw, Trash2, Sparkles } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
@@ -14,8 +15,9 @@ interface AgentCardProps {
 const UUID_RE = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
 
 export function AgentCard({ agent, onClick, onResummon, onDelete }: AgentCardProps) {
+  const { t } = useTranslation("agents");
   const displayName = agent.display_name
-    || (UUID_RE.test(agent.agent_key) ? "Unnamed Agent" : agent.agent_key);
+    || (UUID_RE.test(agent.agent_key) ? t("card.unnamedAgent") : agent.agent_key);
   const selfEvolve = agent.agent_type === "predefined" && Boolean((agent.other_config as Record<string, unknown> | null)?.self_evolve);
 
   // Show agent_key as subtitle only if there's a display_name and agent_key is meaningful
@@ -45,11 +47,11 @@ export function AgentCard({ agent, onClick, onResummon, onDelete }: AgentCardPro
         </div>
         {agent.status === "summoning" ? (
           <Badge variant="outline" className="shrink-0 animate-pulse border-violet-400 text-violet-600 dark:text-violet-400">
-            Summoning...
+            {t("card.summoning")}
           </Badge>
         ) : agent.status === "summon_failed" ? (
           <Badge variant="destructive" className="shrink-0">
-            Failed
+            {t("card.summonFailed")}
           </Badge>
         ) : (
           <Badge variant={agent.status === "active" ? "success" : "secondary"} className="shrink-0">
@@ -80,8 +82,8 @@ export function AgentCard({ agent, onClick, onResummon, onDelete }: AgentCardPro
           </TooltipTrigger>
           <TooltipContent side="top" className="max-w-[260px] text-xs">
             {agent.agent_type === "predefined"
-              ? "Shared context files (SOUL.md, IDENTITY.md, AGENTS.md) with per-user USER.md instances."
-              : "Each user gets their own full set of context files."}
+              ? t("card.predefinedTooltip")
+              : t("card.openTooltip")}
           </TooltipContent>
         </Tooltip>
         {agent.agent_type === "predefined" && (
@@ -92,13 +94,13 @@ export function AgentCard({ agent, onClick, onResummon, onDelete }: AgentCardPro
                 className={`text-[11px] ${selfEvolve ? "bg-violet-100 text-violet-700 hover:bg-violet-100 dark:bg-violet-900/30 dark:text-violet-300" : "text-muted-foreground"}`}
               >
                 <Sparkles className="mr-0.5 h-3 w-3" />
-                {selfEvolve ? "Evolving" : "Static"}
+                {selfEvolve ? t("card.evolving") : t("card.static")}
               </Badge>
             </TooltipTrigger>
             <TooltipContent side="top" className="max-w-[240px] text-xs">
               {selfEvolve
-                ? "Agent can self-evolve its communication style (SOUL.md). Identity and workflow stay fixed."
-                : "Agent style is static. Enable Self-Evolution in settings to allow style adaptation."}
+                ? t("card.evolvingTooltip")
+                : t("card.staticTooltip")}
             </TooltipContent>
           </Tooltip>
         )}
@@ -118,7 +120,7 @@ export function AgentCard({ agent, onClick, onResummon, onDelete }: AgentCardPro
             }}
           >
             <RotateCcw className="h-3 w-3" />
-            Resummon
+            {t("card.resummon")}
           </Button>
         )}
         {onDelete && (
@@ -132,7 +134,7 @@ export function AgentCard({ agent, onClick, onResummon, onDelete }: AgentCardPro
             }}
           >
             <Trash2 className="h-3.5 w-3.5" />
-            Delete
+            {t("card.delete")}
           </Button>
         )}
       </div>
diff --git a/ui/web/src/pages/agents/agent-create-dialog.tsx b/ui/web/src/pages/agents/agent-create-dialog.tsx
index 42960a4a..3a708877 100644
--- a/ui/web/src/pages/agents/agent-create-dialog.tsx
+++ b/ui/web/src/pages/agents/agent-create-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useMemo, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -33,6 +34,7 @@ interface AgentCreateDialogProps {
 }
 
 export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateDialogProps) {
+  const { t } = useTranslation("agents");
   const { providers } = useProviders();
   const [agentKey, setAgentKey] = useState("");
   const [keyTouched, setKeyTouched] = useState(false);
@@ -99,7 +101,7 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
       setSelfEvolve(false);
       setError("");
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to create agent");
+      setError(err instanceof Error ? err.message : t("create.failedToCreate"));
     } finally {
       setLoading(false);
     }
@@ -114,12 +116,12 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="sm:max-w-4xl max-h-[90vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>Create Agent</DialogTitle>
+          <DialogTitle>{t("create.title")}</DialogTitle>
         </DialogHeader>
         <div className="space-y-4 py-4 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
           <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
             <div className="space-y-2">
-              <Label htmlFor="displayName">Display Name *</Label>
+              <Label htmlFor="displayName">{t("create.displayName")}</Label>
               <Input
                 id="displayName"
                 value={displayName}
@@ -129,11 +131,11 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
                     setAgentKey(slugify(displayName.trim()));
                   }
                 }}
-                placeholder="My Agent"
+                placeholder={t("create.displayNamePlaceholder")}
               />
             </div>
             <div className="space-y-2">
-              <Label htmlFor="agentKey">Agent Key *</Label>
+              <Label htmlFor="agentKey">{t("create.agentKey")}</Label>
               <Input
                 id="agentKey"
                 value={agentKey}
@@ -142,18 +144,18 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
                   setAgentKey(e.target.value);
                 }}
                 onBlur={() => setAgentKey(slugify(agentKey))}
-                placeholder="e.g. my-agent"
+                placeholder={t("create.agentKeyPlaceholder")}
               />
-              <p className="text-xs text-muted-foreground">Lowercase, numbers, hyphens</p>
+              <p className="text-xs text-muted-foreground">{t("create.agentKeyHint")}</p>
             </div>
           </div>
           <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
             <div className="space-y-2">
-              <Label>Provider *</Label>
+              <Label>{t("create.provider")}</Label>
               {enabledProviders.length > 0 ? (
                 <Select value={provider} onValueChange={handleProviderChange}>
                   <SelectTrigger>
-                    <SelectValue placeholder="Select provider" />
+                    <SelectValue placeholder={t("create.selectProvider")} />
                   </SelectTrigger>
                   <SelectContent>
                     {enabledProviders.map((p) => (
@@ -172,14 +174,14 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
               )}
             </div>
             <div className="space-y-2">
-              <Label>Model *</Label>
+              <Label>{t("create.model")}</Label>
               <div className="flex gap-2">
                 <div className="flex-1">
                   <Combobox
                     value={model}
                     onChange={setModel}
                     options={models.map((m) => ({ value: m.id, label: m.name }))}
-                    placeholder={modelsLoading ? "Loading models..." : "Enter or select model"}
+                    placeholder={modelsLoading ? t("create.loadingModels") : t("create.enterOrSelectModel")}
                   />
                 </div>
                 <Button
@@ -190,21 +192,21 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
                   disabled={!selectedProviderId || !model.trim() || verifying}
                   onClick={handleVerify}
                 >
-                  {verifying ? "..." : "Check"}
+                  {verifying ? "..." : t("create.check")}
                 </Button>
               </div>
               {verifyResult && (
                 <p className={`text-xs ${verifyResult.valid ? "text-success" : "text-destructive"}`}>
-                  {verifyResult.valid ? "Model verified" : verifyResult.error || "Verification failed"}
+                  {verifyResult.valid ? t("create.modelVerified") : verifyResult.error || t("create.verificationFailed")}
                 </p>
               )}
               {!verifyResult && provider && !modelsLoading && models.length === 0 && (
-                <p className="text-xs text-muted-foreground">This provider doesn't list models — type the model ID manually.</p>
+                <p className="text-xs text-muted-foreground">{t("create.noModelsHint")}</p>
               )}
             </div>
           </div>
           <div className="space-y-2">
-            <Label>Agent Type</Label>
+            <Label>{t("create.agentType")}</Label>
             <div className="flex gap-2">
               <button
                 type="button"
@@ -215,8 +217,8 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
                     : "border-input bg-background hover:bg-accent"
                 }`}
               >
-                Open
-                <span className="block text-xs font-normal opacity-70">Per-user context</span>
+                {t("create.open")}
+                <span className="block text-xs font-normal opacity-70">{t("create.openSubLabel")}</span>
               </button>
               <button
                 type="button"
@@ -227,15 +229,15 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
                     : "border-input bg-background hover:bg-accent"
                 }`}
               >
-                Predefined
-                <span className="block text-xs font-normal opacity-70">Agent-level config</span>
+                {t("create.predefined")}
+                <span className="block text-xs font-normal opacity-70">{t("create.predefinedSubLabel")}</span>
               </button>
             </div>
           </div>
 
           {agentType === "predefined" && (
             <div className="space-y-3">
-              <Label>Describe Your Agent</Label>
+              <Label>{t("create.describeAgent")}</Label>
               <div className="flex flex-wrap gap-1.5">
                 {AGENT_PRESETS.map((preset) => (
                   <button
@@ -251,17 +253,16 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
               <Textarea
                 value={description}
                 onChange={(e) => setDescription(e.target.value)}
-                placeholder="Describe your agent's personality, purpose, and behavior..."
+                placeholder={t("create.descriptionPlaceholder")}
                 className="min-h-[120px]"
               />
               <p className="text-xs text-muted-foreground">
-                AI will automatically generate your agent's context files from this description.
-                Leave empty to start with templates.
+                {t("create.descriptionHint")}
               </p>
               <div className="flex items-center justify-between gap-4 rounded-md border px-3 py-2.5">
                 <div className="space-y-0.5">
-                  <Label htmlFor="create-self-evolve" className="text-sm font-normal">Self-Evolution</Label>
-                  <p className="text-xs text-muted-foreground">Allow agent to evolve its style and tone over time via SOUL.md</p>
+                  <Label htmlFor="create-self-evolve" className="text-sm font-normal">{t("create.selfEvolution")}</Label>
+                  <p className="text-xs text-muted-foreground">{t("create.selfEvolutionHint")}</p>
                 </div>
                 <Switch id="create-self-evolve" checked={selfEvolve} onCheckedChange={setSelfEvolve} />
               </div>
@@ -273,17 +274,17 @@ export function AgentCreateDialog({ open, onOpenChange, onCreate }: AgentCreateD
         </div>
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>
-            Cancel
+            {t("create.cancel")}
           </Button>
           {loading ? (
-            <Button disabled>Creating...</Button>
+            <Button disabled>{t("create.creating")}</Button>
           ) : !verifyResult?.valid && selectedProviderId && model.trim() ? (
             <Button onClick={handleVerifyAndCreate} disabled={verifying || !displayName.trim() || !agentKey.trim() || !isValidSlug(agentKey) || (agentType === "predefined" && !description.trim())}>
-              {verifying ? "Checking..." : "Check & Create"}
+              {verifying ? t("create.checking") : t("create.checkAndCreate")}
             </Button>
           ) : (
             <Button onClick={handleCreate} disabled={!displayName.trim() || !agentKey.trim() || !isValidSlug(agentKey) || !provider.trim() || !model.trim() || !verifyResult?.valid || (agentType === "predefined" && !description.trim())}>
-              Create
+              {t("create.create")}
             </Button>
           )}
         </DialogFooter>
diff --git a/ui/web/src/pages/agents/agent-detail/agent-config-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-config-tab.tsx
index cffd98b2..24ce5ec4 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-config-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-config-tab.tsx
@@ -1,5 +1,6 @@
 import { useState } from "react";
 import { Save, Check, AlertCircle } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Separator } from "@/components/ui/separator";
 import type {
@@ -30,6 +31,8 @@ interface AgentConfigTabProps {
 }
 
 export function AgentConfigTab({ agent, onUpdate }: AgentConfigTabProps) {
+  const { t } = useTranslation("agents");
+
   const [subEnabled, setSubEnabled] = useState(agent.subagents_config != null);
   const [sub, setSub] = useState<SubagentsConfig>(agent.subagents_config ?? {});
 
@@ -48,7 +51,6 @@ export function AgentConfigTab({ agent, onUpdate }: AgentConfigTabProps) {
   const [memEnabled, setMemEnabled] = useState(agent.memory_config != null);
   const [mem, setMem] = useState<MemoryConfig>(agent.memory_config ?? {});
 
-  // Extract managed keys from other_config, manage separately
   const otherObj = (agent.other_config ?? {}) as Record<string, unknown>;
   const initialGates = (Array.isArray(otherObj.quality_gates) ? otherObj.quality_gates : []) as QualityGateConfig[];
   const initialThinkingLevel = (typeof otherObj.thinking_level === "string" ? otherObj.thinking_level : "off");
@@ -83,7 +85,6 @@ export function AgentConfigTab({ agent, onUpdate }: AgentConfigTabProps) {
         sandbox_config: sbEnabled ? sb : null,
         memory_config: memEnabled ? mem : null,
       };
-      // Merge quality_gates back into other_config
       let otherBase: Record<string, unknown> = {};
       if (otherEnabled) {
         try { otherBase = JSON.parse(otherJson); } catch { /* keep empty */ }
@@ -99,7 +100,7 @@ export function AgentConfigTab({ agent, onUpdate }: AgentConfigTabProps) {
       setSaved(true);
       setTimeout(() => setSaved(false), 3000);
     } catch (err) {
-      setSaveError(err instanceof Error ? err.message : "Failed to save");
+      setSaveError(err instanceof Error ? err.message : t("config.failedToSave"));
     } finally {
       setSaving(false);
     }
@@ -177,12 +178,12 @@ export function AgentConfigTab({ agent, onUpdate }: AgentConfigTabProps) {
       <div className="flex items-center justify-end gap-2 pt-2">
         {saved && (
           <span className="flex items-center gap-1 text-sm text-success">
-            <Check className="h-3.5 w-3.5" /> Saved
+            <Check className="h-3.5 w-3.5" /> {t("config.saved")}
           </span>
         )}
         <Button onClick={handleSave} disabled={saving}>
           {!saving && <Save className="h-4 w-4" />}
-          {saving ? "Saving..." : "Save Config"}
+          {saving ? t("config.saving") : t("config.saveConfig")}
         </Button>
       </div>
     </div>
diff --git a/ui/web/src/pages/agents/agent-detail/agent-danger-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-danger-tab.tsx
index b9df8d61..573c367b 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-danger-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-danger-tab.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Trash2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { ConfirmDialog } from "@/components/shared/confirm-dialog";
@@ -11,6 +12,7 @@ interface AgentDangerTabProps {
 }
 
 export function AgentDangerTab({ agent, onDelete, onDeleted }: AgentDangerTabProps) {
+  const { t } = useTranslation("agents");
   const [confirmOpen, setConfirmOpen] = useState(false);
 
   return (
@@ -18,10 +20,9 @@ export function AgentDangerTab({ agent, onDelete, onDeleted }: AgentDangerTabPro
       <div className="rounded-lg border border-destructive/30 bg-destructive/5 p-6">
         <div className="flex items-start justify-between gap-4">
           <div>
-            <h3 className="text-base font-semibold text-destructive">Delete Agent</h3>
+            <h3 className="text-base font-semibold text-destructive">{t("delete.title")}</h3>
             <p className="mt-1 text-sm text-muted-foreground">
-              Permanently delete this agent, all its context files, sessions, and configuration.
-              This action cannot be undone.
+              {t("delete.description")}
             </p>
           </div>
           <Button
@@ -31,12 +32,12 @@ export function AgentDangerTab({ agent, onDelete, onDeleted }: AgentDangerTabPro
             onClick={() => setConfirmOpen(true)}
           >
             <Trash2 className="h-4 w-4" />
-            Delete Agent
+            {t("delete.title")}
           </Button>
         </div>
         {agent.is_default && (
           <p className="mt-3 text-xs text-muted-foreground">
-            The default agent cannot be deleted.
+            {t("delete.defaultCannotDelete")}
           </p>
         )}
       </div>
@@ -44,9 +45,9 @@ export function AgentDangerTab({ agent, onDelete, onDeleted }: AgentDangerTabPro
       <ConfirmDialog
         open={confirmOpen}
         onOpenChange={setConfirmOpen}
-        title="Delete Agent"
-        description={`Are you sure you want to delete "${agent.display_name || agent.agent_key}"? All context files, sessions, and configuration will be permanently removed.`}
-        confirmLabel="Delete"
+        title={t("delete.title")}
+        description={t("delete.detailDescription", { name: agent.display_name || agent.agent_key })}
+        confirmLabel={t("delete.confirmLabel")}
         variant="destructive"
         onConfirm={async () => {
           await onDelete();
diff --git a/ui/web/src/pages/agents/agent-detail/agent-detail-page.tsx b/ui/web/src/pages/agents/agent-detail/agent-detail-page.tsx
index 45b444e8..d6b6b0fa 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-detail-page.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-detail-page.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -24,21 +25,20 @@ interface AgentDetailPageProps {
 
 const UUID_RE = /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
 
-function agentDisplayName(agent: { display_name?: string; agent_key: string }) {
+function agentDisplayName(agent: { display_name?: string; agent_key: string }, unnamedLabel: string) {
   if (agent.display_name) return agent.display_name;
-  if (UUID_RE.test(agent.agent_key)) return "Unnamed Agent";
+  if (UUID_RE.test(agent.agent_key)) return unnamedLabel;
   return agent.agent_key;
 }
 
 function agentSubtitle(agent: { display_name?: string; agent_key: string; id: string }) {
-  // Don't show agent_key if it equals the id (both are UUID) and there's no display_name
   if (!agent.display_name && agent.agent_key === agent.id) return null;
-  // Show agent_key as subtitle (truncate if UUID)
   if (UUID_RE.test(agent.agent_key)) return agent.agent_key.slice(0, 8) + "…";
   return agent.agent_key;
 }
 
 export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
+  const { t } = useTranslation("agents");
   const { agent, files, loading, updateAgent, getFile, setFile, regenerateAgent, resummonAgent, refresh } =
     useAgentDetail(agentId);
   const { deleteAgent: deleteAgentById } = useAgents();
@@ -56,7 +56,6 @@ export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
     setSummoningOpen(true);
   };
 
-  // Refresh data after modal closes (not when completed fires)
   const handleSummoningClose = (open: boolean) => {
     setSummoningOpen(open);
     if (!open) refresh();
@@ -66,7 +65,7 @@ export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
     return <DetailPageSkeleton tabs={6} />;
   }
 
-  const title = agentDisplayName(agent);
+  const title = agentDisplayName(agent, t("card.unnamedAgent"));
   const subtitle = agentSubtitle(agent);
 
   return (
@@ -87,7 +86,7 @@ export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
               <Star className="h-4 w-4 shrink-0 fill-amber-400 text-amber-400" />
             )}
             <Badge variant={agent.status === "active" ? "success" : agent.status === "summon_failed" ? "destructive" : "secondary"}>
-              {agent.status === "summon_failed" ? "Summon Failed" : agent.status}
+              {agent.status === "summon_failed" ? t("detail.summonFailed") : agent.status}
             </Badge>
           </div>
           <div className="mt-1 flex flex-wrap items-center gap-x-2 gap-y-1 text-sm text-muted-foreground">
@@ -103,8 +102,8 @@ export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
               </TooltipTrigger>
               <TooltipContent side="bottom" className="max-w-[260px] text-xs">
                 {agent.agent_type === "predefined"
-                  ? "Shared context files (SOUL.md, IDENTITY.md, AGENTS.md) with per-user USER.md instances."
-                  : "Each user gets their own full set of context files."}
+                  ? t("card.predefinedTooltip")
+                  : t("card.openTooltip")}
               </TooltipContent>
             </Tooltip>
             {agent.agent_type === "predefined" && (() => {
@@ -117,13 +116,13 @@ export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
                       className={`text-[11px] ${evolving ? "bg-violet-100 text-violet-700 hover:bg-violet-100 dark:bg-violet-900/30 dark:text-violet-300" : "text-muted-foreground"}`}
                     >
                       <Sparkles className="mr-0.5 h-3 w-3" />
-                      {evolving ? "Evolving" : "Static"}
+                      {evolving ? t("detail.evolving") : t("detail.static")}
                     </Badge>
                   </TooltipTrigger>
                   <TooltipContent side="bottom" className="max-w-[240px] text-xs">
                     {evolving
-                      ? "Agent can self-evolve its communication style (SOUL.md). Identity and workflow stay fixed."
-                      : "Agent style is static. Enable Self-Evolution in General tab to allow style adaptation."}
+                      ? t("detail.evolvingTooltipDetail")
+                      : t("detail.staticTooltipDetail")}
                   </TooltipContent>
                 </Tooltip>
               );
@@ -150,14 +149,14 @@ export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
       <div className="max-w-4xl rounded-xl border bg-card p-3 shadow-sm sm:p-4">
         <Tabs value={activeTab} onValueChange={setActiveTab}>
           <TabsList className="w-full justify-start overflow-x-auto overflow-y-hidden">
-            <TabsTrigger value="general">General</TabsTrigger>
-            <TabsTrigger value="config">Config</TabsTrigger>
-            <TabsTrigger value="files">Files</TabsTrigger>
-            <TabsTrigger value="shares">Shares</TabsTrigger>
-            <TabsTrigger value="links">Links</TabsTrigger>
-            <TabsTrigger value="skills">Skills</TabsTrigger>
+            <TabsTrigger value="general">{t("detail.tabs.general")}</TabsTrigger>
+            <TabsTrigger value="config">{t("detail.tabs.config")}</TabsTrigger>
+            <TabsTrigger value="files">{t("detail.tabs.files")}</TabsTrigger>
+            <TabsTrigger value="shares">{t("detail.tabs.shares")}</TabsTrigger>
+            <TabsTrigger value="links">{t("detail.tabs.links")}</TabsTrigger>
+            <TabsTrigger value="skills">{t("detail.tabs.skills")}</TabsTrigger>
             {agent.agent_type === "predefined" && (
-              <TabsTrigger value="instances">Instances</TabsTrigger>
+              <TabsTrigger value="instances">{t("detail.tabs.instances")}</TabsTrigger>
             )}
           </TabsList>
 
@@ -213,10 +212,10 @@ export function AgentDetailPage({ agentId, onBack }: AgentDetailPageProps) {
       <ConfirmDeleteDialog
         open={deleteOpen}
         onOpenChange={setDeleteOpen}
-        title="Delete Agent"
-        description={`Are you sure you want to delete "${title}"? All context files, sessions, and configuration will be permanently removed.`}
+        title={t("delete.title")}
+        description={t("delete.detailDescription", { name: title })}
         confirmValue={agent.display_name || agent.agent_key}
-        confirmLabel="Delete"
+        confirmLabel={t("delete.confirmLabel")}
         onConfirm={async () => {
           await deleteAgentById(agentId);
           setDeleteOpen(false);
diff --git a/ui/web/src/pages/agents/agent-detail/agent-files-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-files-tab.tsx
index 9c7ca0b8..f9c454fe 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-files-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-files-tab.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Lock, RotateCcw, Sparkles } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import {
   Dialog,
@@ -34,6 +35,7 @@ export function AgentFilesTab({
   onRegenerate,
   onResummon,
 }: AgentFilesTabProps) {
+  const { t } = useTranslation("agents");
   const userId = useAuthStore((s) => s.userId);
   const [selectedFile, setSelectedFile] = useState<string | null>(null);
   const [content, setContent] = useState("");
@@ -49,7 +51,6 @@ export function AgentFilesTab({
   const isOwner = agent.owner_id === userId;
   const canEdit = !isPredefined || isOwner;
 
-  // Hide MEMORY.json and BOOTSTRAP.md for predefined agents
   const displayFiles = files.filter(
     (f) =>
       f.name !== "MEMORY.json" &&
@@ -113,7 +114,7 @@ export function AgentFilesTab({
           className="gap-1.5"
         >
           <RotateCcw className="h-3.5 w-3.5" />
-          Resummon
+          {t("files.resummon")}
         </Button>
       )}
       {onRegenerate && (
@@ -124,7 +125,7 @@ export function AgentFilesTab({
           className="gap-1.5"
         >
           <Sparkles className="h-3.5 w-3.5" />
-          Edit with AI
+          {t("files.editWithAi")}
         </Button>
       )}
     </>
@@ -136,10 +137,8 @@ export function AgentFilesTab({
         <div className="flex items-start gap-3 rounded-lg border border-amber-500/30 bg-amber-500/5 p-4">
           <Lock className="mt-0.5 h-5 w-5 shrink-0 text-amber-600 dark:text-amber-400" />
           <div className="text-sm">
-            <p className="font-medium">Read-only</p>
-            <p className="text-muted-foreground">
-              Only the agent owner can edit predefined context files.
-            </p>
+            <p className="font-medium">{t("files.readOnly")}</p>
+            <p className="text-muted-foreground">{t("files.readOnlyDesc")}</p>
           </div>
         </div>
       )}
@@ -177,13 +176,11 @@ export function AgentFilesTab({
           <DialogHeader>
             <DialogTitle className="flex items-center gap-2">
               <RotateCcw className="h-4 w-4" />
-              Resummon Agent
+              {t("files.resummonTitle")}
             </DialogTitle>
           </DialogHeader>
           <p className="text-sm text-muted-foreground">
-            This will regenerate <strong>SOUL.md</strong>, <strong>IDENTITY.md</strong>, and
-            optionally <strong>USER_PREDEFINED.md</strong> from scratch using the original
-            description. Any manual edits to these files will be overwritten.
+            {t("files.resummonDesc")}
           </p>
           <DialogFooter>
             <Button
@@ -191,7 +188,7 @@ export function AgentFilesTab({
               onClick={() => setResummonOpen(false)}
               disabled={resummonning}
             >
-              Cancel
+              {t("files.cancel")}
             </Button>
             <Button
               variant="destructive"
@@ -200,7 +197,7 @@ export function AgentFilesTab({
               className="gap-1.5"
             >
               <RotateCcw className="h-3.5 w-3.5" />
-              {resummonning ? "Summoning..." : "Resummon"}
+              {resummonning ? t("files.summoning") : t("files.resummonConfirm")}
             </Button>
           </DialogFooter>
         </DialogContent>
diff --git a/ui/web/src/pages/agents/agent-detail/agent-general-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-general-tab.tsx
index 8f6ded48..f0157b1c 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-general-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-general-tab.tsx
@@ -1,5 +1,6 @@
 import { useState, useCallback } from "react";
 import { Save, Check, AlertCircle, Sparkles, Info } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Separator } from "@/components/ui/separator";
 import { Switch } from "@/components/ui/switch";
@@ -13,6 +14,8 @@ interface AgentGeneralTabProps {
 }
 
 export function AgentGeneralTab({ agent, onUpdate }: AgentGeneralTabProps) {
+  const { t } = useTranslation("agents");
+
   // Identity
   const [displayName, setDisplayName] = useState(agent.display_name ?? "");
   const [frontmatter, setFrontmatter] = useState(agent.frontmatter ?? "");
@@ -47,7 +50,6 @@ export function AgentGeneralTab({ agent, onUpdate }: AgentGeneralTabProps) {
     setSaveError(null);
     setSaved(false);
     try {
-      // Merge self_evolve into other_config without losing other keys
       const updatedOtherConfig = { ...otherCfg, self_evolve: selfEvolve };
       await onUpdate({
         display_name: displayName,
@@ -64,7 +66,7 @@ export function AgentGeneralTab({ agent, onUpdate }: AgentGeneralTabProps) {
       setSaved(true);
       setTimeout(() => setSaved(false), 3000);
     } catch (err) {
-      setSaveError(err instanceof Error ? err.message : "Failed to save");
+      setSaveError(err instanceof Error ? err.message : t("general.failedToSave"));
     } finally {
       setSaving(false);
     }
@@ -115,15 +117,15 @@ export function AgentGeneralTab({ agent, onUpdate }: AgentGeneralTabProps) {
           <div className="space-y-3">
             <div className="flex items-center gap-3">
               <Sparkles className="h-4 w-4 text-violet-500" />
-              <h3 className="text-sm font-medium">Self-Evolution</h3>
+              <h3 className="text-sm font-medium">{t("general.selfEvolution")}</h3>
             </div>
             <div className="flex items-center justify-between gap-4">
               <div className="space-y-1">
                 <Label htmlFor="self-evolve" className="text-sm font-normal">
-                  Allow agent to evolve its communication style
+                  {t("general.selfEvolutionLabel")}
                 </Label>
                 <p className="text-xs text-muted-foreground">
-                  When enabled, the agent can update its SOUL.md to refine tone, vocabulary, and response style based on interactions. Identity, name, and operating instructions remain locked.
+                  {t("general.selfEvolutionHint")}
                 </p>
               </div>
               <Switch
@@ -135,7 +137,7 @@ export function AgentGeneralTab({ agent, onUpdate }: AgentGeneralTabProps) {
             {selfEvolve && (
               <div className="flex items-start gap-2 rounded-md border border-violet-200 bg-violet-50 px-3 py-2 text-xs text-violet-700 dark:border-violet-800 dark:bg-violet-950/30 dark:text-violet-300">
                 <Info className="mt-0.5 h-3.5 w-3.5 shrink-0" />
-                <span>Agent will evolve its style over time through SOUL.md updates. Only style and tone are affected — identity and workflow rules stay fixed.</span>
+                <span>{t("general.selfEvolutionInfo")}</span>
               </div>
             )}
           </div>
@@ -152,12 +154,12 @@ export function AgentGeneralTab({ agent, onUpdate }: AgentGeneralTabProps) {
       <div className="flex items-center justify-end gap-2">
         {saved && (
           <span className="flex items-center gap-1 text-sm text-success">
-            <Check className="h-3.5 w-3.5" /> Saved
+            <Check className="h-3.5 w-3.5" /> {t("general.saved")}
           </span>
         )}
         <Button onClick={handleSave} disabled={saving || llmSaveBlocked}>
           {!saving && <Save className="h-4 w-4" />}
-          {saving ? "Saving..." : "Save Changes"}
+          {saving ? t("general.saving") : t("general.saveChanges")}
         </Button>
       </div>
     </div>
diff --git a/ui/web/src/pages/agents/agent-detail/agent-instances-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-instances-tab.tsx
index 899b08da..d42f92eb 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-instances-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-instances-tab.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save, Check, AlertCircle, Users, FileText } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { Textarea } from "@/components/ui/textarea";
@@ -10,6 +11,7 @@ interface AgentInstancesTabProps {
 }
 
 export function AgentInstancesTab({ agentId }: AgentInstancesTabProps) {
+  const { t } = useTranslation("agents");
   const { instances, loading, saving, getFiles, setFile } = useAgentInstances(agentId);
   const [selected, setSelected] = useState<string | null>(null);
   const [content, setContent] = useState("");
@@ -18,7 +20,6 @@ export function AgentInstancesTab({ agentId }: AgentInstancesTabProps) {
   const [saved, setSaved] = useState(false);
   const [error, setError] = useState<string | null>(null);
 
-  // Load USER.md when an instance is selected
   useEffect(() => {
     if (!selected) return;
     let cancelled = false;
@@ -31,12 +32,12 @@ export function AgentInstancesTab({ agentId }: AgentInstancesTabProps) {
       setContent(c);
       setOriginalContent(c);
     }).catch((err) => {
-      if (!cancelled) setError(err instanceof Error ? err.message : "Failed to load files");
+      if (!cancelled) setError(err instanceof Error ? err.message : t("instances.loading"));
     }).finally(() => {
       if (!cancelled) setLoadingFiles(false);
     });
     return () => { cancelled = true; };
-  }, [selected, getFiles]);
+  }, [selected, getFiles, t]);
 
   const handleSave = async () => {
     if (!selected) return;
@@ -48,22 +49,22 @@ export function AgentInstancesTab({ agentId }: AgentInstancesTabProps) {
       setSaved(true);
       setTimeout(() => setSaved(false), 3000);
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to save");
+      setError(err instanceof Error ? err.message : t("instances.saving"));
     }
   };
 
   const isDirty = content !== originalContent;
 
   if (loading) {
-    return <div className="py-8 text-center text-sm text-muted-foreground">Loading instances...</div>;
+    return <div className="py-8 text-center text-sm text-muted-foreground">{t("instances.loadingInstances")}</div>;
   }
 
   if (instances.length === 0) {
     return (
       <div className="flex flex-col items-center gap-2 py-12 text-center">
         <Users className="h-8 w-8 text-muted-foreground/50" />
-        <p className="text-sm text-muted-foreground">No user instances yet.</p>
-        <p className="text-xs text-muted-foreground/70">Instances are created when users interact with this agent.</p>
+        <p className="text-sm text-muted-foreground">{t("instances.noInstances")}</p>
+        <p className="text-xs text-muted-foreground/70">{t("instances.noInstancesDesc")}</p>
       </div>
     );
   }
@@ -89,11 +90,11 @@ export function AgentInstancesTab({ agentId }: AgentInstancesTabProps) {
       <div className="flex flex-1 flex-col gap-3">
         {!selected ? (
           <div className="flex flex-1 items-center justify-center text-sm text-muted-foreground">
-            Select an instance to view and edit its USER.md
+            {t("instances.selectInstance")}
           </div>
         ) : loadingFiles ? (
           <div className="flex flex-1 items-center justify-center text-sm text-muted-foreground">
-            Loading...
+            {t("instances.loading")}
           </div>
         ) : (
           <>
@@ -118,12 +119,12 @@ export function AgentInstancesTab({ agentId }: AgentInstancesTabProps) {
             <div className="flex items-center justify-end gap-2">
               {saved && (
                 <span className="flex items-center gap-1 text-sm text-success">
-                  <Check className="h-3.5 w-3.5" /> Saved
+                  <Check className="h-3.5 w-3.5" /> {t("instances.saved")}
                 </span>
               )}
               <Button onClick={handleSave} disabled={saving || !isDirty} size="sm">
                 {!saving && <Save className="h-4 w-4" />}
-                {saving ? "Saving..." : "Save"}
+                {saving ? t("instances.saving") : t("instances.save")}
               </Button>
             </div>
           </>
diff --git a/ui/web/src/pages/agents/agent-detail/agent-links-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-links-tab.tsx
index 57437404..0c029b3f 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-links-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-links-tab.tsx
@@ -1,6 +1,7 @@
 import { useState, useEffect, useMemo } from "react";
 import { Link } from "react-router";
 import { Info } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { ConfirmDialog } from "@/components/shared/confirm-dialog";
 import { useAgentLinks } from "../hooks/use-agent-links";
 import { useAgents } from "../hooks/use-agents";
@@ -13,6 +14,7 @@ interface AgentLinksTabProps {
 }
 
 export function AgentLinksTab({ agentId }: AgentLinksTabProps) {
+  const { t } = useTranslation("agents");
   const { links, loading, load, createLink, updateLink, deleteLink } =
     useAgentLinks(agentId);
   const { agents } = useAgents();
@@ -27,7 +29,6 @@ export function AgentLinksTab({ agentId }: AgentLinksTabProps) {
     load();
   }, [load]);
 
-  // Only predefined agents can be delegation targets (open agents have no agent-level context)
   const agentOptions = useMemo(
     () =>
       agents
@@ -49,11 +50,11 @@ export function AgentLinksTab({ agentId }: AgentLinksTabProps) {
       <div className="flex items-start gap-3 rounded-lg border border-blue-200 bg-blue-50 px-4 py-3 dark:border-blue-900 dark:bg-blue-950/30">
         <Info className="mt-0.5 h-4 w-4 shrink-0 text-blue-600 dark:text-blue-400" />
         <p className="text-sm text-blue-800 dark:text-blue-300">
-          For multi-agent collaboration with task tracking and quality control, consider using{" "}
+          {t("links.teamsHint").split("Agent Teams")[0]}
           <Link to={ROUTES.TEAMS} className="font-medium underline underline-offset-2 hover:text-blue-900 dark:hover:text-blue-200">
             Agent Teams
-          </Link>{" "}
-          instead. Agent Links are best for simple 1-to-1 delegation between two agents.
+          </Link>
+          {t("links.teamsHint").split("Agent Teams")[1]}
         </p>
       </div>
 
@@ -79,9 +80,9 @@ export function AgentLinksTab({ agentId }: AgentLinksTabProps) {
       <ConfirmDialog
         open={!!deleteTarget}
         onOpenChange={() => setDeleteTarget(null)}
-        title="Delete Link"
-        description={`Remove the delegation link to "${deleteTarget?.name}"? Agents will no longer be able to delegate to each other through this link.`}
-        confirmLabel="Delete"
+        title={t("links.deleteTitle")}
+        description={t("links.deleteDesc", { name: deleteTarget?.name })}
+        confirmLabel={t("delete.confirmLabel")}
         variant="destructive"
         onConfirm={async () => {
           if (deleteTarget) {
diff --git a/ui/web/src/pages/agents/agent-detail/agent-shares-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-shares-tab.tsx
index b3256d27..9108ccc9 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-shares-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-shares-tab.tsx
@@ -1,5 +1,6 @@
 import { useState } from "react";
 import { Plus, Trash2, Users } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -32,6 +33,7 @@ function roleBadgeVariant(role: string) {
 }
 
 export function AgentSharesTab({ agentId }: AgentSharesTabProps) {
+  const { t } = useTranslation("agents");
   const { shares, loading, addShare, revokeShare } = useAgentShares(agentId);
   const [newUserId, setNewUserId] = useState("");
   const [newRole, setNewRole] = useState("user");
@@ -52,22 +54,22 @@ export function AgentSharesTab({ agentId }: AgentSharesTabProps) {
     <div className="max-w-2xl space-y-6">
       {/* Add share form */}
       <div className="rounded-lg border p-4">
-        <h3 className="mb-3 text-sm font-medium">Grant Access</h3>
+        <h3 className="mb-3 text-sm font-medium">{t("shares.grantAccess")}</h3>
         <div className="flex flex-col gap-3 sm:flex-row sm:items-end">
           <div className="flex-1 space-y-1.5">
-            <Label htmlFor="shareUserId">User ID</Label>
+            <Label htmlFor="shareUserId">{t("shares.userId")}</Label>
             <Input
               id="shareUserId"
               value={newUserId}
               onChange={(e) => setNewUserId(e.target.value)}
-              placeholder="Enter user ID..."
+              placeholder={t("shares.userIdPlaceholder")}
               onKeyDown={(e) => {
                 if (e.key === "Enter" && newUserId.trim()) handleAddShare();
               }}
             />
           </div>
           <div className="w-full space-y-1.5 sm:w-36">
-            <Label>Role</Label>
+            <Label>{t("shares.role")}</Label>
             <Select value={newRole} onValueChange={setNewRole}>
               <SelectTrigger>
                 <SelectValue />
@@ -83,27 +85,27 @@ export function AgentSharesTab({ agentId }: AgentSharesTabProps) {
           </div>
           <Button onClick={handleAddShare} disabled={!newUserId.trim()} className="gap-1.5">
             <Plus className="h-4 w-4" />
-            Share
+            {t("shares.share")}
           </Button>
         </div>
       </div>
 
       {/* Share list */}
       {loading && shares.length === 0 ? (
-        <div className="py-8 text-center text-sm text-muted-foreground">Loading shares...</div>
+        <div className="py-8 text-center text-sm text-muted-foreground">{t("shares.loadingShares")}</div>
       ) : shares.length === 0 ? (
         <div className="flex flex-col items-center gap-2 py-8 text-center">
           <Users className="h-8 w-8 text-muted-foreground/50" />
-          <p className="text-sm text-muted-foreground">No shares yet</p>
+          <p className="text-sm text-muted-foreground">{t("shares.noShares")}</p>
           <p className="text-xs text-muted-foreground">
-            Share this agent with other users by entering their User ID above.
+            {t("shares.noSharesDesc")}
           </p>
         </div>
       ) : (
         <div className="overflow-x-auto rounded-lg border">
           <div className="grid min-w-[300px] grid-cols-[1fr_100px_48px] items-center gap-2 border-b bg-muted/50 px-4 py-2.5 text-xs font-medium text-muted-foreground">
-            <span>User</span>
-            <span>Role</span>
+            <span>{t("shares.user")}</span>
+            <span>{t("shares.role")}</span>
             <span />
           </div>
           {shares.map((share) => (
@@ -136,9 +138,9 @@ export function AgentSharesTab({ agentId }: AgentSharesTabProps) {
       <ConfirmDialog
         open={!!revokeTarget}
         onOpenChange={() => setRevokeTarget(null)}
-        title="Revoke Share"
-        description={`Revoke access for user "${revokeTarget}"? They will no longer be able to use this agent.`}
-        confirmLabel="Revoke"
+        title={t("shares.revokeTitle")}
+        description={t("shares.revokeDesc", { userId: revokeTarget })}
+        confirmLabel={t("shares.revoke")}
         variant="destructive"
         onConfirm={async () => {
           if (revokeTarget) {
diff --git a/ui/web/src/pages/agents/agent-detail/agent-skills-tab.tsx b/ui/web/src/pages/agents/agent-detail/agent-skills-tab.tsx
index 441bd718..7d3a7c9b 100644
--- a/ui/web/src/pages/agents/agent-detail/agent-skills-tab.tsx
+++ b/ui/web/src/pages/agents/agent-detail/agent-skills-tab.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Badge } from "@/components/ui/badge";
 import { Switch } from "@/components/ui/switch";
 import { TableSkeleton } from "@/components/shared/loading-skeleton";
@@ -25,6 +26,7 @@ const visibilityVariant = (v: string) => {
 };
 
 export function AgentSkillsTab({ agentId }: AgentSkillsTabProps) {
+  const { t } = useTranslation("agents");
   const { skills, loading, grantSkill, revokeSkill } = useAgentSkills(agentId);
   const [search, setSearch] = useState("");
   const [toggling, setToggling] = useState<string | null>(null);
@@ -57,8 +59,8 @@ export function AgentSkillsTab({ agentId }: AgentSkillsTabProps) {
     return (
       <EmptyState
         icon={Zap}
-        title="No skills available"
-        description="Upload skills in the Skills page to grant them to agents."
+        title={t("skills.noSkillsAvailable")}
+        description={t("skills.noSkillsDesc")}
       />
     );
   }
@@ -67,9 +69,17 @@ export function AgentSkillsTab({ agentId }: AgentSkillsTabProps) {
     <div className="max-w-4xl space-y-4">
       <div className="flex items-center justify-between">
         <p className="text-sm text-muted-foreground">
-          {skills.filter((s) => s.granted).length} of {skills.length} skills granted
+          {t("skills.skillsGranted", {
+            granted: skills.filter((s) => s.granted).length,
+            total: skills.length,
+          })}
         </p>
-        <SearchInput value={search} onChange={setSearch} placeholder="Filter skills..." className="w-full sm:w-64" />
+        <SearchInput
+          value={search}
+          onChange={setSearch}
+          placeholder={t("skills.filterSkills")}
+          className="w-full sm:w-64"
+        />
       </div>
 
       <div className="divide-y rounded-lg border">
@@ -95,7 +105,7 @@ export function AgentSkillsTab({ agentId }: AgentSkillsTabProps) {
         ))}
         {filtered.length === 0 && (
           <div className="px-4 py-8 text-center text-sm text-muted-foreground">
-            No skills match your search.
+            {t("skills.noSkillsMatch")}
           </div>
         )}
       </div>
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/compaction-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/compaction-section.tsx
index 7ddfe59f..9d8d6248 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/compaction-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/compaction-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { Switch } from "@/components/ui/switch";
 import type { CompactionConfig } from "@/types/agent";
@@ -11,16 +12,18 @@ interface CompactionSectionProps {
 }
 
 export function CompactionSection({ enabled, value, onToggle, onChange }: CompactionSectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.compaction";
   return (
     <ConfigSection
-      title="Compaction"
-      description="Context window compaction and memory flush settings"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Minimum tokens reserved for the LLM response. Higher values give more room for output but reduce available context for history.">Reserve Tokens Floor</InfoLabel>
+          <InfoLabel tip="Minimum tokens reserved for the LLM response. Higher values give more room for output but reduce available context for history.">{t(`${s}.reserveTokensFloor`)}</InfoLabel>
           <Input
             type="number"
             placeholder="20000"
@@ -29,7 +32,7 @@ export function CompactionSection({ enabled, value, onToggle, onChange }: Compac
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Maximum fraction of the context window used for conversation history before compaction triggers (e.g. 0.75 = 75%).">Max History Share (0-1)</InfoLabel>
+          <InfoLabel tip="Maximum fraction of the context window used for conversation history before compaction triggers (e.g. 0.75 = 75%).">{t(`${s}.maxHistoryShare`)}</InfoLabel>
           <Input
             type="number"
             step="0.05"
@@ -41,7 +44,7 @@ export function CompactionSection({ enabled, value, onToggle, onChange }: Compac
       </div>
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Minimum number of messages in history before compaction can trigger, regardless of token usage.">Min Messages</InfoLabel>
+          <InfoLabel tip="Minimum number of messages in history before compaction can trigger, regardless of token usage.">{t(`${s}.minMessages`)}</InfoLabel>
           <Input
             type="number"
             placeholder="50"
@@ -50,7 +53,7 @@ export function CompactionSection({ enabled, value, onToggle, onChange }: Compac
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Number of recent messages to preserve after compaction. The rest is replaced by a summary.">Keep Last Messages</InfoLabel>
+          <InfoLabel tip="Number of recent messages to preserve after compaction. The rest is replaced by a summary.">{t(`${s}.keepLastMessages`)}</InfoLabel>
           <Input
             type="number"
             placeholder="4"
@@ -67,11 +70,11 @@ export function CompactionSection({ enabled, value, onToggle, onChange }: Compac
               onChange({ ...value, memoryFlush: { ...value.memoryFlush, enabled: v } })
             }
           />
-          <InfoLabel tip="When enabled, compacted history is also saved to long-term memory for future retrieval.">Memory Flush</InfoLabel>
+          <InfoLabel tip="When enabled, compacted history is also saved to long-term memory for future retrieval.">{t(`${s}.memoryFlush`)}</InfoLabel>
         </div>
         {value.memoryFlush?.enabled && (
           <div className="space-y-2 pl-6">
-            <InfoLabel tip="Token count threshold that triggers memory flush. When summary exceeds this, older memories are flushed to storage.">Soft Threshold (tokens)</InfoLabel>
+            <InfoLabel tip="Token count threshold that triggers memory flush. When summary exceeds this, older memories are flushed to storage.">{t(`${s}.softThreshold`)}</InfoLabel>
             <Input
               type="number"
               placeholder="4000"
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/config-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/config-section.tsx
index 721313a6..50c488e4 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/config-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/config-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Switch } from "@/components/ui/switch";
 
 export { InfoLabel } from "@/components/shared/info-label";
@@ -17,6 +18,7 @@ export function ConfigSection({
   onToggle,
   children,
 }: ConfigSectionProps) {
+  const { t } = useTranslation("agents");
   return (
     <section className="space-y-3">
       <div className="flex items-center justify-between">
@@ -30,7 +32,7 @@ export function ConfigSection({
         <div className="rounded-lg border p-3 space-y-4 sm:p-4">{children}</div>
       ) : (
         <p className="text-xs text-muted-foreground italic">
-          Using global defaults from config.json
+          {t("config.usingGlobalDefaults")}
         </p>
       )}
     </section>
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/context-pruning-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/context-pruning-section.tsx
index 50332efb..4cfb0cf8 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/context-pruning-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/context-pruning-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { Switch } from "@/components/ui/switch";
 import {
@@ -18,16 +19,18 @@ interface ContextPruningSectionProps {
 }
 
 export function ContextPruningSection({ enabled, value, onToggle, onChange }: ContextPruningSectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.contextPruning";
   return (
     <ConfigSection
-      title="Context Pruning"
-      description="Trim old tool results to save context window"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Pruning strategy. 'cache-ttl' trims old tool results based on their position in the conversation.">Mode</InfoLabel>
+          <InfoLabel tip="Pruning strategy. 'cache-ttl' trims old tool results based on their position in the conversation.">{t(`${s}.mode`)}</InfoLabel>
           <Select
             value={value.mode ?? ""}
             onValueChange={(v) =>
@@ -42,7 +45,7 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
           </Select>
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Number of recent assistant turns whose tool results are always kept intact, never pruned.">Keep Last Assistants</InfoLabel>
+          <InfoLabel tip="Number of recent assistant turns whose tool results are always kept intact, never pruned.">{t(`${s}.keepLastAssistants`)}</InfoLabel>
           <Input
             type="number"
             placeholder="3"
@@ -55,7 +58,7 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
       </div>
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Context usage ratio (0-1) at which soft trimming begins. E.g. 0.3 means trimming starts when context is 30% full.">Soft Trim Ratio (0-1)</InfoLabel>
+          <InfoLabel tip="Context usage ratio (0-1) at which soft trimming begins. E.g. 0.3 means trimming starts when context is 30% full.">{t(`${s}.softTrimRatio`)}</InfoLabel>
           <Input
             type="number"
             step="0.05"
@@ -65,7 +68,7 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Context usage ratio (0-1) at which hard clearing kicks in. E.g. 0.5 means full clearing at 50% context usage.">Hard Clear Ratio (0-1)</InfoLabel>
+          <InfoLabel tip="Context usage ratio (0-1) at which hard clearing kicks in. E.g. 0.5 means full clearing at 50% context usage.">{t(`${s}.hardClearRatio`)}</InfoLabel>
           <Input
             type="number"
             step="0.05"
@@ -76,7 +79,7 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
         </div>
       </div>
       <div className="space-y-2">
-        <InfoLabel tip="Only tool results with at least this many characters are eligible for pruning. Shorter results are left untouched.">Min Prunable Tool Chars</InfoLabel>
+        <InfoLabel tip="Only tool results with at least this many characters are eligible for pruning. Shorter results are left untouched.">{t(`${s}.minPrunableToolChars`)}</InfoLabel>
         <Input
           type="number"
           placeholder="50000"
@@ -89,10 +92,10 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
 
       {/* Soft Trim */}
       <div className="space-y-3 rounded-md border border-dashed p-3">
-        <h4 className="text-xs font-medium text-muted-foreground">Soft Trim</h4>
+        <h4 className="text-xs font-medium text-muted-foreground">{t(`${s}.softTrim`)}</h4>
         <div className="grid grid-cols-1 gap-4 sm:grid-cols-3">
           <div className="space-y-2">
-            <InfoLabel tip="Tool results longer than this will be soft-trimmed, keeping only head and tail portions.">Max Chars</InfoLabel>
+            <InfoLabel tip="Tool results longer than this will be soft-trimmed, keeping only head and tail portions.">{t(`${s}.maxChars`)}</InfoLabel>
             <Input
               type="number"
               placeholder="4000"
@@ -103,7 +106,7 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
             />
           </div>
           <div className="space-y-2">
-            <InfoLabel tip="Number of characters to keep from the beginning of a trimmed tool result.">Head Chars</InfoLabel>
+            <InfoLabel tip="Number of characters to keep from the beginning of a trimmed tool result.">{t(`${s}.headChars`)}</InfoLabel>
             <Input
               type="number"
               placeholder="1500"
@@ -114,7 +117,7 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
             />
           </div>
           <div className="space-y-2">
-            <InfoLabel tip="Number of characters to keep from the end of a trimmed tool result.">Tail Chars</InfoLabel>
+            <InfoLabel tip="Number of characters to keep from the end of a trimmed tool result.">{t(`${s}.tailChars`)}</InfoLabel>
             <Input
               type="number"
               placeholder="1500"
@@ -129,7 +132,7 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
 
       {/* Hard Clear */}
       <div className="space-y-3 rounded-md border border-dashed p-3">
-        <h4 className="text-xs font-medium text-muted-foreground">Hard Clear</h4>
+        <h4 className="text-xs font-medium text-muted-foreground">{t(`${s}.hardClear`)}</h4>
         <div className="flex items-center gap-2">
           <Switch
             checked={value.hardClear?.enabled ?? true}
@@ -137,10 +140,10 @@ export function ContextPruningSection({ enabled, value, onToggle, onChange }: Co
               onChange({ ...value, hardClear: { ...value.hardClear, enabled: v } })
             }
           />
-          <InfoLabel tip="When enabled, old tool results beyond the hard clear ratio are replaced entirely with placeholder text.">Enabled</InfoLabel>
+          <InfoLabel tip="When enabled, old tool results beyond the hard clear ratio are replaced entirely with placeholder text.">{t(`${s}.enabled`)}</InfoLabel>
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Text that replaces cleared tool results. Helps the agent understand content was removed.">Placeholder Text</InfoLabel>
+          <InfoLabel tip="Text that replaces cleared tool results. Helps the agent understand content was removed.">{t(`${s}.placeholderText`)}</InfoLabel>
           <Input
             placeholder="[Old tool result content cleared]"
             value={value.hardClear?.placeholder ?? ""}
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/memory-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/memory-section.tsx
index 6c09f850..f8a6b71e 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/memory-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/memory-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { Switch } from "@/components/ui/switch";
 import type { MemoryConfig } from "@/types/agent";
@@ -12,10 +13,12 @@ interface MemorySectionProps {
 }
 
 export function MemorySection({ enabled, value, onToggle, onChange }: MemorySectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.memory";
   return (
     <ConfigSection
-      title="Memory"
-      description="Semantic memory search and embedding configuration"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
@@ -24,15 +27,15 @@ export function MemorySection({ enabled, value, onToggle, onChange }: MemorySect
           checked={value.enabled ?? true}
           onCheckedChange={(v) => onChange({ ...value, enabled: v })}
         />
-        <InfoLabel tip="Enable or disable the memory system for this agent. When enabled, the agent can store and recall information across sessions.">Enabled</InfoLabel>
+        <InfoLabel tip="Enable or disable the memory system for this agent. When enabled, the agent can store and recall information across sessions.">{t("configSections.contextPruning.enabled")}</InfoLabel>
       </div>
       <ProviderModelSelect
         provider={value.embedding_provider ?? ""}
         onProviderChange={(v) => onChange({ ...value, embedding_provider: v || undefined })}
         model={value.embedding_model ?? ""}
         onModelChange={(v) => onChange({ ...value, embedding_model: v || undefined })}
-        providerLabel="Embedding Provider"
-        modelLabel="Embedding Model"
+        providerLabel={t(`${s}.embeddingProvider`)}
+        modelLabel={t(`${s}.embeddingModel`)}
         providerTip="LLM provider used for generating text embeddings. Leave empty to auto-detect from the agent's main provider."
         modelTip="Embedding model name (e.g. text-embedding-3-small). Must be supported by the provider."
         providerPlaceholder="(auto)"
@@ -40,7 +43,7 @@ export function MemorySection({ enabled, value, onToggle, onChange }: MemorySect
       />
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Maximum number of memory entries returned per search query.">Max Results</InfoLabel>
+          <InfoLabel tip="Maximum number of memory entries returned per search query.">{t(`${s}.maxResults`)}</InfoLabel>
           <Input
             type="number"
             placeholder="6"
@@ -49,7 +52,7 @@ export function MemorySection({ enabled, value, onToggle, onChange }: MemorySect
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Maximum character length for each memory chunk. Longer content is split into smaller chunks before storing.">Max Chunk Length</InfoLabel>
+          <InfoLabel tip="Maximum character length for each memory chunk. Longer content is split into smaller chunks before storing.">{t(`${s}.maxChunkLen`)}</InfoLabel>
           <Input
             type="number"
             placeholder="1000"
@@ -60,7 +63,7 @@ export function MemorySection({ enabled, value, onToggle, onChange }: MemorySect
       </div>
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Weight for vector (semantic) similarity in hybrid search scoring. Higher values prioritize meaning over keywords.">Vector Weight</InfoLabel>
+          <InfoLabel tip="Weight for vector (semantic) similarity in hybrid search scoring. Higher values prioritize meaning over keywords.">{t(`${s}.vectorWeight`)}</InfoLabel>
           <Input
             type="number"
             step="0.1"
@@ -70,7 +73,7 @@ export function MemorySection({ enabled, value, onToggle, onChange }: MemorySect
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Weight for text (keyword/BM25) similarity in hybrid search scoring. Higher values prioritize exact keyword matches.">Text Weight</InfoLabel>
+          <InfoLabel tip="Weight for text (keyword/BM25) similarity in hybrid search scoring. Higher values prioritize exact keyword matches.">{t(`${s}.textWeight`)}</InfoLabel>
           <Input
             type="number"
             step="0.1"
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/other-config-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/other-config-section.tsx
index 05113bc6..65a7284f 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/other-config-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/other-config-section.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Textarea } from "@/components/ui/textarea";
 import { Button } from "@/components/ui/button";
 import { ConfigSection } from "./config-section";
@@ -11,6 +12,8 @@ interface OtherConfigSectionProps {
 }
 
 export function OtherConfigSection({ enabled, value, onToggle, onChange }: OtherConfigSectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.otherConfig";
   const [validJson, setValidJson] = useState(true);
 
   useEffect(() => {
@@ -33,8 +36,8 @@ export function OtherConfigSection({ enabled, value, onToggle, onChange }: Other
 
   return (
     <ConfigSection
-      title="Other Config"
-      description="Additional JSON config for advanced settings not covered by other sections"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
@@ -47,9 +50,9 @@ export function OtherConfigSection({ enabled, value, onToggle, onChange }: Other
       />
       <div className="flex items-center justify-between">
         <Button variant="ghost" size="sm" onClick={handleFormat} disabled={!validJson} className="h-7 px-2 text-xs">
-          Format JSON
+          {t(`${s}.formatJson`)}
         </Button>
-        {!validJson && <span className="text-xs text-destructive">Invalid JSON syntax</span>}
+        {!validJson && <span className="text-xs text-destructive">{t(`${s}.invalidJson`)}</span>}
       </div>
     </ConfigSection>
   );
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/quality-gates-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/quality-gates-section.tsx
index 5cc8cb6a..69dd9f17 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/quality-gates-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/quality-gates-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Plus, Trash2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -28,6 +29,9 @@ const defaultGate: QualityGateConfig = {
 };
 
 export function QualityGatesSection({ enabled, value, onToggle, onChange }: QualityGatesSectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.qualityGates";
+
   const updateGate = (i: number, patch: Partial<QualityGateConfig>) => {
     const next = [...value];
     next[i] = { ...next[i], ...patch } as QualityGateConfig;
@@ -44,20 +48,20 @@ export function QualityGatesSection({ enabled, value, onToggle, onChange }: Qual
 
   return (
     <ConfigSection
-      title="Quality Gates"
-      description="Validate delegation output before returning to the caller"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
       {value.length === 0 ? (
         <p className="text-xs text-muted-foreground italic">
-          No quality gates configured. Click &ldquo;Add Gate&rdquo; to create one.
+          {t(`${s}.noGates`)}
         </p>
       ) : (
         value.map((gate, i) => (
           <div key={i} className="relative rounded-md border p-3 space-y-3">
             <div className="flex items-center justify-between">
-              <span className="text-xs font-medium text-muted-foreground">Gate #{i + 1}</span>
+              <span className="text-xs font-medium text-muted-foreground">{t(`${s}.gateNumber`, { number: i + 1 })}</span>
               <Button
                 variant="ghost"
                 size="icon"
@@ -69,7 +73,7 @@ export function QualityGatesSection({ enabled, value, onToggle, onChange }: Qual
             </div>
             <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
               <div className="space-y-2">
-                <InfoLabel tip="Validation method. 'Agent' delegates to a reviewer agent, 'Command' runs a shell command and checks exit code.">Type</InfoLabel>
+                <InfoLabel tip="Validation method. 'Agent' delegates to a reviewer agent, 'Command' runs a shell command and checks exit code.">{t(`${s}.type`)}</InfoLabel>
                 <Select
                   value={gate.type}
                   onValueChange={(v) => updateGate(i, {
@@ -88,7 +92,7 @@ export function QualityGatesSection({ enabled, value, onToggle, onChange }: Qual
               <div className="space-y-2">
                 {gate.type === "agent" ? (
                   <>
-                    <InfoLabel tip="Key of the agent used to review and validate the delegation output.">Reviewer Agent Key</InfoLabel>
+                    <InfoLabel tip="Key of the agent used to review and validate the delegation output.">{t(`${s}.reviewerAgentKey`)}</InfoLabel>
                     <Input
                       placeholder="qa-reviewer"
                       value={gate.agent ?? ""}
@@ -97,7 +101,7 @@ export function QualityGatesSection({ enabled, value, onToggle, onChange }: Qual
                   </>
                 ) : (
                   <>
-                    <InfoLabel tip="Shell command to run for validation. Exit code 0 = pass, non-zero = fail.">Command</InfoLabel>
+                    <InfoLabel tip="Shell command to run for validation. Exit code 0 = pass, non-zero = fail.">{t(`${s}.command`)}</InfoLabel>
                     <Input
                       placeholder="npm test"
                       value={gate.command ?? ""}
@@ -113,11 +117,11 @@ export function QualityGatesSection({ enabled, value, onToggle, onChange }: Qual
                   checked={gate.block_on_failure}
                   onCheckedChange={(v) => updateGate(i, { block_on_failure: v })}
                 />
-                <InfoLabel tip="When enabled, a failed gate prevents the result from being returned to the caller and triggers retries.">Block on Failure</InfoLabel>
+                <InfoLabel tip="When enabled, a failed gate prevents the result from being returned to the caller and triggers retries.">{t(`${s}.blockOnFailure`)}</InfoLabel>
               </div>
               {gate.block_on_failure && (
                 <div className="space-y-2">
-                  <InfoLabel tip="Number of times to retry the delegation if the quality gate fails.">Max Retries</InfoLabel>
+                  <InfoLabel tip="Number of times to retry the delegation if the quality gate fails.">{t(`${s}.maxRetries`)}</InfoLabel>
                   <Input
                     type="number"
                     placeholder="2"
@@ -129,7 +133,7 @@ export function QualityGatesSection({ enabled, value, onToggle, onChange }: Qual
             </div>
             <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
               <div className="space-y-2">
-                <InfoLabel tip="Maximum time in seconds to wait for the quality gate check to complete before timing out.">Timeout (seconds)</InfoLabel>
+                <InfoLabel tip="Maximum time in seconds to wait for the quality gate check to complete before timing out.">{t(`${s}.timeout`)}</InfoLabel>
                 <Input
                   type="number"
                   placeholder="120"
@@ -142,7 +146,7 @@ export function QualityGatesSection({ enabled, value, onToggle, onChange }: Qual
         ))
       )}
       <Button variant="outline" size="sm" onClick={addGate} className="gap-1">
-        <Plus className="h-3.5 w-3.5" /> Add Gate
+        <Plus className="h-3.5 w-3.5" /> {t(`${s}.addGate`)}
       </Button>
     </ConfigSection>
   );
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/sandbox-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/sandbox-section.tsx
index 272603ae..28260d45 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/sandbox-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/sandbox-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { Switch } from "@/components/ui/switch";
 import {
@@ -18,16 +19,18 @@ interface SandboxSectionProps {
 }
 
 export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.sandbox";
   return (
     <ConfigSection
-      title="Sandbox"
-      description="Docker sandbox for code execution isolation"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="'off' disables sandboxing, 'non-main' sandboxes only sub-agents, 'all' sandboxes every execution including the main agent.">Mode</InfoLabel>
+          <InfoLabel tip="'off' disables sandboxing, 'non-main' sandboxes only sub-agents, 'all' sandboxes every execution including the main agent.">{t(`${s}.mode`)}</InfoLabel>
           <Select
             value={value.mode ?? ""}
             onValueChange={(v) => onChange({ ...value, mode: v as SandboxConfig["mode"] })}
@@ -41,7 +44,7 @@ export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSe
           </Select>
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="How the sandbox accesses the host workspace. 'none' = isolated, 'ro' = read-only mount, 'rw' = full read-write access.">Workspace Access</InfoLabel>
+          <InfoLabel tip="How the sandbox accesses the host workspace. 'none' = isolated, 'ro' = read-only mount, 'rw' = full read-write access.">{t(`${s}.workspaceAccess`)}</InfoLabel>
           <Select
             value={value.workspace_access ?? ""}
             onValueChange={(v) =>
@@ -58,7 +61,7 @@ export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSe
         </div>
       </div>
       <div className="space-y-2">
-        <InfoLabel tip="Docker image used for the sandbox container. Must be pre-built and available locally.">Image</InfoLabel>
+        <InfoLabel tip="Docker image used for the sandbox container. Must be pre-built and available locally.">{t(`${s}.image`)}</InfoLabel>
         <Input
           placeholder="goclaw-sandbox:bookworm-slim"
           value={value.image ?? ""}
@@ -67,7 +70,7 @@ export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSe
       </div>
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Container lifecycle scope. 'session' = one container per chat session, 'agent' = shared across sessions, 'shared' = shared across all agents.">Scope</InfoLabel>
+          <InfoLabel tip="Container lifecycle scope. 'session' = one container per chat session, 'agent' = shared across sessions, 'shared' = shared across all agents.">{t(`${s}.scope`)}</InfoLabel>
           <Select
             value={value.scope ?? ""}
             onValueChange={(v) => onChange({ ...value, scope: v as SandboxConfig["scope"] })}
@@ -81,7 +84,7 @@ export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSe
           </Select>
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Maximum execution time in seconds for each command run inside the sandbox.">Timeout (sec)</InfoLabel>
+          <InfoLabel tip="Maximum execution time in seconds for each command run inside the sandbox.">{t(`${s}.timeout`)}</InfoLabel>
           <Input
             type="number"
             placeholder="300"
@@ -92,7 +95,7 @@ export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSe
       </div>
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Maximum memory allocation for the sandbox container in megabytes.">Memory (MB)</InfoLabel>
+          <InfoLabel tip="Maximum memory allocation for the sandbox container in megabytes.">{t(`${s}.memoryMb`)}</InfoLabel>
           <Input
             type="number"
             placeholder="512"
@@ -101,7 +104,7 @@ export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSe
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="CPU allocation for the sandbox container. Fractional values allowed (e.g. 0.5 = half a core).">CPUs</InfoLabel>
+          <InfoLabel tip="CPU allocation for the sandbox container. Fractional values allowed (e.g. 0.5 = half a core).">{t(`${s}.cpus`)}</InfoLabel>
           <Input
             type="number"
             step="0.5"
@@ -116,7 +119,7 @@ export function SandboxSection({ enabled, value, onToggle, onChange }: SandboxSe
           checked={value.network_enabled ?? false}
           onCheckedChange={(v) => onChange({ ...value, network_enabled: v })}
         />
-        <InfoLabel tip="Allow the sandbox container to access the network. Disable for fully isolated execution.">Network Enabled</InfoLabel>
+        <InfoLabel tip="Allow the sandbox container to access the network. Disable for fully isolated execution.">{t(`${s}.networkEnabled`)}</InfoLabel>
       </div>
     </ConfigSection>
   );
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/subagents-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/subagents-section.tsx
index 72d22ef9..b5f78d99 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/subagents-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/subagents-section.tsx
@@ -1,4 +1,5 @@
 import { useMemo } from "react";
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { Combobox } from "@/components/ui/combobox";
 import {
@@ -21,25 +22,23 @@ interface SubagentsSectionProps {
 }
 
 export function SubagentsSection({ enabled, value, onToggle, onChange }: SubagentsSectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.subagents";
   const { providers } = useProviders();
   const enabledProviders = providers.filter((p) => p.enabled);
-  // Use the first enabled provider for model list suggestions
-  const defaultProvider = useMemo(
-    () => enabledProviders[0],
-    [enabledProviders],
-  );
+  const defaultProvider = useMemo(() => enabledProviders[0], [enabledProviders]);
   const { models, loading: modelsLoading } = useProviderModels(defaultProvider?.id, defaultProvider?.provider_type);
 
   return (
     <ConfigSection
-      title="Subagents"
-      description="Controls sub-agent spawning limits and behavior"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Maximum number of sub-agents that can run simultaneously for this agent.">Max Concurrent</InfoLabel>
+          <InfoLabel tip="Maximum number of sub-agents that can run simultaneously for this agent.">{t(`${s}.maxConcurrent`)}</InfoLabel>
           <Input
             type="number"
             placeholder="8"
@@ -48,7 +47,7 @@ export function SubagentsSection({ enabled, value, onToggle, onChange }: Subagen
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="How many levels deep sub-agents can spawn other sub-agents. Depth 1 means only the parent can spawn.">Max Spawn Depth</InfoLabel>
+          <InfoLabel tip="How many levels deep sub-agents can spawn other sub-agents. Depth 1 means only the parent can spawn.">{t(`${s}.maxSpawnDepth`)}</InfoLabel>
           <Select
             value={String(value.maxSpawnDepth ?? "")}
             onValueChange={(v) => onChange({ ...value, maxSpawnDepth: Number(v) })}
@@ -64,7 +63,7 @@ export function SubagentsSection({ enabled, value, onToggle, onChange }: Subagen
       </div>
       <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
         <div className="space-y-2">
-          <InfoLabel tip="Maximum number of sub-agents a single parent agent can spawn in one session.">Max Children Per Agent</InfoLabel>
+          <InfoLabel tip="Maximum number of sub-agents a single parent agent can spawn in one session.">{t(`${s}.maxChildrenPerAgent`)}</InfoLabel>
           <Input
             type="number"
             placeholder="5"
@@ -73,7 +72,7 @@ export function SubagentsSection({ enabled, value, onToggle, onChange }: Subagen
           />
         </div>
         <div className="space-y-2">
-          <InfoLabel tip="Idle time in minutes before a sub-agent session is automatically archived and cleaned up.">Archive After (minutes)</InfoLabel>
+          <InfoLabel tip="Idle time in minutes before a sub-agent session is automatically archived and cleaned up.">{t(`${s}.archiveAfter`)}</InfoLabel>
           <Input
             type="number"
             placeholder="60"
@@ -83,12 +82,12 @@ export function SubagentsSection({ enabled, value, onToggle, onChange }: Subagen
         </div>
       </div>
       <div className="space-y-2">
-        <InfoLabel tip="LLM model for sub-agents. Leave empty to inherit the parent agent's model.">Model Override</InfoLabel>
+        <InfoLabel tip="LLM model for sub-agents. Leave empty to inherit the parent agent's model.">{t(`${s}.modelOverride`)}</InfoLabel>
         <Combobox
           value={value.model ?? ""}
           onChange={(v) => onChange({ ...value, model: v || undefined })}
           options={models.map((m) => ({ value: m.id, label: m.name }))}
-          placeholder={modelsLoading ? "Loading models..." : "(inherit from agent)"}
+          placeholder={modelsLoading ? "Loading models..." : t(`${s}.inheritFromAgent`)}
         />
       </div>
     </ConfigSection>
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/thinking-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/thinking-section.tsx
index 1a8bec4d..e9395935 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/thinking-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/thinking-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import {
   Select,
   SelectContent,
@@ -7,12 +8,7 @@ import {
 } from "@/components/ui/select";
 import { InfoLabel } from "./config-section";
 
-const THINKING_LEVELS = [
-  { value: "off", label: "Off", description: "No extended thinking" },
-  { value: "low", label: "Low", description: "~4K token budget" },
-  { value: "medium", label: "Medium", description: "~10-16K token budget" },
-  { value: "high", label: "High", description: "~32K token budget" },
-] as const;
+const THINKING_LEVEL_KEYS = ["off", "low", "medium", "high"] as const;
 
 interface ThinkingSectionProps {
   value: string;
@@ -20,25 +16,33 @@ interface ThinkingSectionProps {
 }
 
 export function ThinkingSection({ value, onChange }: ThinkingSectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.thinking";
+
+  const levels = THINKING_LEVEL_KEYS.map((key) => ({
+    value: key,
+    label: t(`${s}.${key}`),
+    description: t(`${s}.${key}Desc`),
+  }));
+
   return (
     <section className="space-y-3">
       <div>
-        <h3 className="text-sm font-medium">Extended Thinking</h3>
+        <h3 className="text-sm font-medium">{t(`${s}.title`)}</h3>
         <p className="text-xs text-muted-foreground">
-          Allow the model to reason before responding. Higher levels use more
-          tokens but produce better results on complex tasks.
+          {t(`${s}.description`)}
         </p>
       </div>
       <div className="space-y-2">
         <InfoLabel tip="Thinking level controls the token budget for reasoning. Anthropic uses budget_tokens, OpenAI uses reasoning_effort, DashScope uses thinking_budget. Token budgets vary by provider.">
-          Thinking Level
+          {t(`${s}.thinkingLevel`)}
         </InfoLabel>
         <Select value={value || "off"} onValueChange={onChange}>
           <SelectTrigger className="w-48">
             <SelectValue />
           </SelectTrigger>
           <SelectContent>
-            {THINKING_LEVELS.map((level) => (
+            {levels.map((level) => (
               <SelectItem key={level.value} value={level.value}>
                 <span>{level.label}</span>
                 <span className="ml-2 text-xs text-muted-foreground">
diff --git a/ui/web/src/pages/agents/agent-detail/config-sections/tool-policy-section.tsx b/ui/web/src/pages/agents/agent-detail/config-sections/tool-policy-section.tsx
index 37236c2e..89845999 100644
--- a/ui/web/src/pages/agents/agent-detail/config-sections/tool-policy-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/config-sections/tool-policy-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import {
   Select,
   SelectContent,
@@ -17,15 +18,17 @@ interface ToolPolicySectionProps {
 }
 
 export function ToolPolicySection({ enabled, value, onToggle, onChange }: ToolPolicySectionProps) {
+  const { t } = useTranslation("agents");
+  const s = "configSections.toolPolicy";
   return (
     <ConfigSection
-      title="Tool Policy"
-      description="Control which tools this agent can use"
+      title={t(`${s}.title`)}
+      description={t(`${s}.description`)}
       enabled={enabled}
       onToggle={onToggle}
     >
       <div className="space-y-2">
-        <InfoLabel tip="Base tool profile. 'full' allows all tools, 'coding' includes filesystem/runtime/sessions/memory, 'messaging' includes messaging/sessions, 'minimal' allows only session_status.">Profile</InfoLabel>
+        <InfoLabel tip="Base tool profile. 'full' allows all tools, 'coding' includes filesystem/runtime/sessions/memory, 'messaging' includes messaging/sessions, 'minimal' allows only session_status.">{t(`${s}.profile`)}</InfoLabel>
         <Select
           value={value.profile ?? ""}
           onValueChange={(v) => onChange({ ...value, profile: v || undefined })}
@@ -40,27 +43,27 @@ export function ToolPolicySection({ enabled, value, onToggle, onChange }: ToolPo
         </Select>
       </div>
       <div className="space-y-2">
-        <InfoLabel tip="Explicit allowlist. Only these tools will be available (overrides profile). Leave empty to use profile defaults.">Allow</InfoLabel>
+        <InfoLabel tip="Explicit allowlist. Only these tools will be available (overrides profile). Leave empty to use profile defaults.">{t(`${s}.allow`)}</InfoLabel>
         <ToolNameSelect
           value={value.allow ?? []}
           onChange={(v) => onChange({ ...value, allow: v.length > 0 ? v : undefined })}
-          placeholder="Select tools to allow..."
+          placeholder={t(`${s}.selectToolsAllow`)}
         />
       </div>
       <div className="space-y-2">
-        <InfoLabel tip="Denylist. These tools will be blocked even if allowed by the profile.">Deny</InfoLabel>
+        <InfoLabel tip="Denylist. These tools will be blocked even if allowed by the profile.">{t(`${s}.deny`)}</InfoLabel>
         <ToolNameSelect
           value={value.deny ?? []}
           onChange={(v) => onChange({ ...value, deny: v.length > 0 ? v : undefined })}
-          placeholder="Select tools to deny..."
+          placeholder={t(`${s}.selectToolsDeny`)}
         />
       </div>
       <div className="space-y-2">
-        <InfoLabel tip="Additional tools on top of profile defaults. Useful for enabling optional tools without overriding the whole profile.">Also Allow</InfoLabel>
+        <InfoLabel tip="Additional tools on top of profile defaults. Useful for enabling optional tools without overriding the whole profile.">{t(`${s}.alsoAllow`)}</InfoLabel>
         <ToolNameSelect
           value={value.alsoAllow ?? []}
           onChange={(v) => onChange({ ...value, alsoAllow: v.length > 0 ? v : undefined })}
-          placeholder="Select additional tools..."
+          placeholder={t(`${s}.selectToolsAlsoAllow`)}
         />
       </div>
     </ConfigSection>
diff --git a/ui/web/src/pages/agents/agent-detail/file-sections/file-editor.tsx b/ui/web/src/pages/agents/agent-detail/file-sections/file-editor.tsx
index f1717f59..390953b3 100644
--- a/ui/web/src/pages/agents/agent-detail/file-sections/file-editor.tsx
+++ b/ui/web/src/pages/agents/agent-detail/file-sections/file-editor.tsx
@@ -1,4 +1,5 @@
 import type { ReactNode } from "react";
+import { useTranslation } from "react-i18next";
 import { Save } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Textarea } from "@/components/ui/textarea";
@@ -27,6 +28,8 @@ export function FileEditor({
   onSave,
   headerActions,
 }: FileEditorProps) {
+  const { t } = useTranslation("agents");
+
   if (!fileName) {
     return (
       <div className="flex flex-1 flex-col">
@@ -34,7 +37,7 @@ export function FileEditor({
           <div className="mb-2 flex justify-end gap-2">{headerActions}</div>
         )}
         <div className="flex flex-1 items-center justify-center text-sm text-muted-foreground">
-          Select a file to {canEdit ? "edit" : "view"}
+          {canEdit ? t("files.selectFileToEdit") : t("files.selectFileToView")}
         </div>
       </div>
     );
@@ -56,14 +59,14 @@ export function FileEditor({
           {canEdit && (
             <Button size="sm" onClick={onSave} disabled={!dirty || saving}>
               {!saving && <Save className="h-3.5 w-3.5" />}
-              {saving ? "Saving..." : "Save"}
+              {saving ? t("files.saving") : t("files.save")}
             </Button>
           )}
         </div>
       </div>
       {loading && !content ? (
         <div className="flex flex-1 items-center justify-center text-sm text-muted-foreground">
-          Loading...
+          {t("files.loading")}
         </div>
       ) : (
         <Textarea
diff --git a/ui/web/src/pages/agents/agent-detail/file-sections/file-sidebar.tsx b/ui/web/src/pages/agents/agent-detail/file-sections/file-sidebar.tsx
index 265d861a..e73ca484 100644
--- a/ui/web/src/pages/agents/agent-detail/file-sections/file-sidebar.tsx
+++ b/ui/web/src/pages/agents/agent-detail/file-sections/file-sidebar.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { FileText } from "lucide-react";
 import { Badge } from "@/components/ui/badge";
 import type { BootstrapFile } from "@/types/agent";
@@ -42,6 +43,7 @@ export function FileSidebar({
   onSelect,
   isUserScoped,
 }: FileSidebarProps) {
+  const { t } = useTranslation("agents");
   return (
     <div className="w-56 shrink-0 overflow-y-auto rounded-lg bg-muted/40 p-2">
       <div className="space-y-0.5">
@@ -67,19 +69,19 @@ export function FileSidebar({
                 <div className="truncate">{file.name}</div>
                 {userScoped ? (
                   <Badge variant="outline" className="mt-0.5 text-[10px]">
-                    per-user
+                    {t("files.perUser")}
                   </Badge>
                 ) : file.missing ? (
                   <span className="text-[10px] text-muted-foreground/60">
-                    empty
+                    {t("files.emptyFile")}
                   </span>
                 ) : (
                   <div className="text-[10px] text-muted-foreground/60">
-                    Est {formatTokenCount(
+                    {t("files.estTokens", { tokens: formatTokenCount(
                       file.content
                         ? estimateTokensFromContent(file.content)
                         : estimateTokensFromBytes(file.size),
-                    )} tokens
+                    ) })}
                   </div>
                 )}
               </div>
diff --git a/ui/web/src/pages/agents/agent-detail/file-sections/open-agent-empty-state.tsx b/ui/web/src/pages/agents/agent-detail/file-sections/open-agent-empty-state.tsx
index 173ec6d3..529b4662 100644
--- a/ui/web/src/pages/agents/agent-detail/file-sections/open-agent-empty-state.tsx
+++ b/ui/web/src/pages/agents/agent-detail/file-sections/open-agent-empty-state.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { FileText, Info } from "lucide-react";
 import { Badge } from "@/components/ui/badge";
 import type { BootstrapFile } from "@/types/agent";
@@ -8,31 +9,28 @@ interface OpenAgentEmptyStateProps {
 }
 
 export function OpenAgentEmptyState({ files }: OpenAgentEmptyStateProps) {
+  const { t } = useTranslation("agents");
   return (
     <div className="max-w-2xl space-y-4">
       <div className="flex items-start gap-3 rounded-lg border border-info/30 bg-sky-500/5 p-4">
         <Info className="mt-0.5 h-5 w-5 shrink-0 text-sky-600 dark:text-sky-400" />
         <div className="space-y-2 text-sm">
-          <p className="font-medium">Open Agent - Per-User Context Files</p>
+          <p className="font-medium">{t("files.openAgentTitle")}</p>
           <p className="text-muted-foreground">
-            This is an <strong>open</strong> agent. Context files (AGENTS.md,
-            SOUL.md, TOOLS.md, etc.) are personalized for each user. They are
-            automatically created from templates when a user first chats with
-            this agent.
+            {t("files.openAgentDesc1")}
           </p>
           <p className="text-muted-foreground">
-            Agent-level files shown here are empty because open agents store all
-            context per-user in the{" "}
+            {t("files.openAgentDesc2pre")}
             <code className="rounded bg-muted px-1 py-0.5 text-xs">
               user_context_files
-            </code>{" "}
-            table.
+            </code>
+            {t("files.openAgentDesc2post")}
           </p>
         </div>
       </div>
 
       <div className="rounded-lg border p-4">
-        <h4 className="mb-3 text-sm font-medium">Context Files</h4>
+        <h4 className="mb-3 text-sm font-medium">{t("files.contextFiles")}</h4>
         <div className="space-y-2">
           {files.map((file) => (
             <div
@@ -43,11 +41,11 @@ export function OpenAgentEmptyState({ files }: OpenAgentEmptyStateProps) {
               <div className="min-w-0 flex-1">
                 <div className="text-sm font-medium">{file.name}</div>
                 <div className="text-xs text-muted-foreground">
-                  {FILE_DESCRIPTIONS[file.name] || "Context file"}
+                  {FILE_DESCRIPTIONS[file.name] || t("files.contextFile")}
                 </div>
               </div>
               <Badge variant="outline" className="shrink-0 text-[10px]">
-                per-user
+                {t("files.perUser")}
               </Badge>
             </div>
           ))}
diff --git a/ui/web/src/pages/agents/agent-detail/file-sections/regenerate-dialog.tsx b/ui/web/src/pages/agents/agent-detail/file-sections/regenerate-dialog.tsx
index dcd2233b..972054a0 100644
--- a/ui/web/src/pages/agents/agent-detail/file-sections/regenerate-dialog.tsx
+++ b/ui/web/src/pages/agents/agent-detail/file-sections/regenerate-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Sparkles } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Textarea } from "@/components/ui/textarea";
@@ -21,6 +22,7 @@ export function RegenerateDialog({
   onOpenChange,
   onRegenerate,
 }: RegenerateDialogProps) {
+  const { t } = useTranslation("agents");
   const [prompt, setPrompt] = useState("");
   const [regenerating, setRegenerating] = useState(false);
 
@@ -42,18 +44,17 @@ export function RegenerateDialog({
         <DialogHeader>
           <DialogTitle className="flex items-center gap-2">
             <Sparkles className="h-4 w-4" />
-            Edit with AI
+            {t("fileEditor.editWithAi")}
           </DialogTitle>
         </DialogHeader>
         <div className="space-y-3 py-2">
           <p className="text-sm text-muted-foreground">
-            Describe what you want to change. AI will read the current files and
-            update them accordingly.
+            {t("fileEditor.editAiDescription")}
           </p>
           <Textarea
             value={prompt}
             onChange={(e) => setPrompt(e.target.value)}
-            placeholder="e.g. Make the agent more formal, add Vietnamese language support, change the name to Luna..."
+            placeholder={t("fileEditor.editAiPlaceholder")}
             className="min-h-[100px] max-h-[300px] resize-none"
           />
         </div>
@@ -63,7 +64,7 @@ export function RegenerateDialog({
             onClick={() => onOpenChange(false)}
             disabled={regenerating}
           >
-            Cancel
+            {t("fileEditor.cancel")}
           </Button>
           <Button
             onClick={handleSubmit}
@@ -71,7 +72,7 @@ export function RegenerateDialog({
             className="gap-1.5"
           >
             <Sparkles className="h-3.5 w-3.5" />
-            {regenerating ? "Sending..." : "Regenerate"}
+            {regenerating ? t("fileEditor.sending") : t("fileEditor.regenerate")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/agents/agent-detail/general-sections/identity-section.tsx b/ui/web/src/pages/agents/agent-detail/general-sections/identity-section.tsx
index 469ca969..0b28d559 100644
--- a/ui/web/src/pages/agents/agent-detail/general-sections/identity-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/general-sections/identity-section.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Copy, Check } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -35,6 +36,7 @@ export function IdentitySection({
   isDefault,
   onIsDefaultChange,
 }: IdentitySectionProps) {
+  const { t } = useTranslation("agents");
   const [copied, setCopied] = useState(false);
 
   const copyAgentKey = async () => {
@@ -45,10 +47,10 @@ export function IdentitySection({
 
   return (
     <section className="space-y-4">
-      <h3 className="text-sm font-medium text-muted-foreground">Identity</h3>
+      <h3 className="text-sm font-medium text-muted-foreground">{t("identity.title")}</h3>
       <div className="space-y-4 rounded-lg border p-4">
         <div className="space-y-2">
-          <Label>Agent Key</Label>
+          <Label>{t("identity.agentKey")}</Label>
           <div className="flex items-center gap-2">
             <Input value={agentKey} disabled className="font-mono text-sm" />
             <Button
@@ -65,46 +67,46 @@ export function IdentitySection({
             </Button>
           </div>
           <p className="text-xs text-muted-foreground">
-            Unique identifier, cannot be changed.
+            {t("identity.agentKeyHint")}
           </p>
         </div>
         <div className="space-y-2">
-          <Label htmlFor="displayName">Display Name</Label>
+          <Label htmlFor="displayName">{t("identity.displayName")}</Label>
           <Input
             id="displayName"
             value={displayName}
             onChange={(e) => onDisplayNameChange(e.target.value)}
-            placeholder="e.g. My Assistant"
+            placeholder={t("identity.displayNamePlaceholder")}
           />
           <p className="text-xs text-muted-foreground">
-            Friendly name shown in the UI. Leave empty to use the agent key.
+            {t("identity.displayNameHint")}
           </p>
         </div>
         <div className="space-y-2">
-          <Label htmlFor="frontmatter">Expertise Summary</Label>
+          <Label htmlFor="frontmatter">{t("identity.expertiseSummary")}</Label>
           <Input
             id="frontmatter"
             value={frontmatter}
             onChange={(e) => onFrontmatterChange(e.target.value)}
-            placeholder="e.g. Chiêm tinh, bói toán, tử vi, thần số học"
+            placeholder={t("identity.expertiseSummaryPlaceholder")}
           />
           <p className="text-xs text-muted-foreground">
-            Short description of this agent's expertise. Used for delegation discovery.
+            {t("identity.expertiseSummaryHint")}
           </p>
         </div>
         <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
           <div className="space-y-2">
-            <Label>Status</Label>
+            <Label>{t("identity.status")}</Label>
             <Select value={status} onValueChange={onStatusChange}>
               <SelectTrigger>
                 <SelectValue />
               </SelectTrigger>
               <SelectContent>
-                <SelectItem value="active">Active</SelectItem>
-                <SelectItem value="inactive">Inactive</SelectItem>
+                <SelectItem value="active">{t("identity.active")}</SelectItem>
+                <SelectItem value="inactive">{t("identity.inactive")}</SelectItem>
                 {status === "summon_failed" && (
                   <SelectItem value="summon_failed" disabled>
-                    Summon Failed
+                    {t("identity.summonFailed")}
                   </SelectItem>
                 )}
               </SelectContent>
@@ -113,7 +115,7 @@ export function IdentitySection({
           <div className="flex items-end pb-2">
             <div className="flex items-center gap-2">
               <Switch checked={isDefault} onCheckedChange={onIsDefaultChange} />
-              <Label>Default Agent</Label>
+              <Label>{t("identity.defaultAgent")}</Label>
             </div>
           </div>
         </div>
diff --git a/ui/web/src/pages/agents/agent-detail/general-sections/llm-config-section.tsx b/ui/web/src/pages/agents/agent-detail/general-sections/llm-config-section.tsx
index 2931dd2b..3ea3c58b 100644
--- a/ui/web/src/pages/agents/agent-detail/general-sections/llm-config-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/general-sections/llm-config-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { ProviderModelSelect } from "@/components/shared/provider-model-select";
@@ -30,9 +31,10 @@ export function LlmConfigSection({
   savedModel,
   onSaveBlockedChange,
 }: LlmConfigSectionProps) {
+  const { t } = useTranslation("agents");
   return (
     <section className="space-y-4">
-      <h3 className="text-sm font-medium text-muted-foreground">LLM Configuration</h3>
+      <h3 className="text-sm font-medium text-muted-foreground">{t("llmConfig.title")}</h3>
       <div className="space-y-4 rounded-lg border p-4">
         <ProviderModelSelect
           provider={provider}
@@ -47,7 +49,7 @@ export function LlmConfigSection({
         />
         <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
           <div className="space-y-2">
-            <Label htmlFor="contextWindow">Context Window</Label>
+            <Label htmlFor="contextWindow">{t("llmConfig.contextWindow")}</Label>
             <Input
               id="contextWindow"
               type="number"
@@ -55,10 +57,10 @@ export function LlmConfigSection({
               onChange={(e) => onContextWindowChange(Number(e.target.value) || 0)}
               placeholder="200000"
             />
-            <p className="text-xs text-muted-foreground">Token limit for the model context.</p>
+            <p className="text-xs text-muted-foreground">{t("llmConfig.contextWindowHint")}</p>
           </div>
           <div className="space-y-2">
-            <Label htmlFor="maxToolIterations">Max Tool Iterations</Label>
+            <Label htmlFor="maxToolIterations">{t("llmConfig.maxToolIterations")}</Label>
             <Input
               id="maxToolIterations"
               type="number"
@@ -66,7 +68,7 @@ export function LlmConfigSection({
               onChange={(e) => onMaxToolIterationsChange(Number(e.target.value) || 0)}
               placeholder="25"
             />
-            <p className="text-xs text-muted-foreground">Max tool calls per request.</p>
+            <p className="text-xs text-muted-foreground">{t("llmConfig.maxToolIterationsHint")}</p>
           </div>
         </div>
       </div>
diff --git a/ui/web/src/pages/agents/agent-detail/general-sections/workspace-section.tsx b/ui/web/src/pages/agents/agent-detail/general-sections/workspace-section.tsx
index 69b9a022..c03809a0 100644
--- a/ui/web/src/pages/agents/agent-detail/general-sections/workspace-section.tsx
+++ b/ui/web/src/pages/agents/agent-detail/general-sections/workspace-section.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Label } from "@/components/ui/label";
 import { Switch } from "@/components/ui/switch";
 
@@ -12,18 +13,18 @@ export function WorkspaceSection({
   restrictToWorkspace,
   onRestrictChange,
 }: WorkspaceSectionProps) {
+  const { t } = useTranslation("agents");
   return (
     <section className="space-y-4">
-      <h3 className="text-sm font-medium text-muted-foreground">Workspace</h3>
+      <h3 className="text-sm font-medium text-muted-foreground">{t("workspace.title")}</h3>
       <div className="space-y-4 rounded-lg border p-4">
         <div className="space-y-2">
-          <Label>Workspace Path</Label>
+          <Label>{t("workspace.workspacePath")}</Label>
           <p className="rounded-md border bg-muted/50 px-3 py-2 font-mono text-sm text-muted-foreground">
-            {workspace || "No workspace configured"}
+            {workspace || t("workspace.noWorkspace")}
           </p>
           <p className="text-xs text-muted-foreground">
-            Automatically assigned when the agent is created. Per-user
-            subdirectories are created at runtime.
+            {t("workspace.workspacePathHint")}
           </p>
         </div>
         <div className="flex items-center gap-2">
@@ -32,9 +33,9 @@ export function WorkspaceSection({
             onCheckedChange={onRestrictChange}
           />
           <div>
-            <Label>Restrict to Workspace</Label>
+            <Label>{t("workspace.restrictToWorkspace")}</Label>
             <p className="text-xs text-muted-foreground">
-              Confine file access strictly within the workspace path.
+              {t("workspace.restrictToWorkspaceHint")}
             </p>
           </div>
         </div>
diff --git a/ui/web/src/pages/agents/agent-detail/link-sections/link-create-form.tsx b/ui/web/src/pages/agents/agent-detail/link-sections/link-create-form.tsx
index 2e166053..6b58d0e0 100644
--- a/ui/web/src/pages/agents/agent-detail/link-sections/link-create-form.tsx
+++ b/ui/web/src/pages/agents/agent-detail/link-sections/link-create-form.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Plus, ChevronDown, ChevronRight } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -26,6 +27,7 @@ interface LinkCreateFormProps {
 }
 
 export function LinkCreateForm({ agentOptions, onSubmit }: LinkCreateFormProps) {
+  const { t } = useTranslation("agents");
   const [targetAgent, setTargetAgent] = useState("");
   const [direction, setDirection] = useState("outbound");
   const [description, setDescription] = useState("");
@@ -64,20 +66,20 @@ export function LinkCreateForm({ agentOptions, onSubmit }: LinkCreateFormProps)
 
   return (
     <div className="rounded-lg border p-4">
-      <h3 className="mb-3 text-sm font-medium">Create Link</h3>
+      <h3 className="mb-3 text-sm font-medium">{t("links.createLink")}</h3>
       <div className="space-y-3">
         <div className="flex flex-col gap-3 sm:flex-row sm:items-end">
           <div className="flex-1 space-y-1.5">
-            <Label>Target Agent</Label>
+            <Label>{t("links.targetAgent")}</Label>
             <Combobox
               value={targetAgent}
               onChange={setTargetAgent}
               options={agentOptions}
-              placeholder="Select or search agent..."
+              placeholder={t("links.selectAgent")}
             />
           </div>
           <div className="w-full space-y-1.5 sm:w-44">
-            <Label>Direction</Label>
+            <Label>{t("links.direction")}</Label>
             <Select value={direction} onValueChange={setDirection}>
               <SelectTrigger>
                 <SelectValue />
@@ -99,15 +101,15 @@ export function LinkCreateForm({ agentOptions, onSubmit }: LinkCreateFormProps)
         </p>
         <div className="flex flex-col gap-3 sm:flex-row sm:items-end">
           <div className="flex-1 space-y-1.5">
-            <Label>Description</Label>
+            <Label>{t("links.description")}</Label>
             <Input
               value={description}
               onChange={(e) => setDescription(e.target.value)}
-              placeholder="Optional description of the link..."
+              placeholder={t("links.descriptionPlaceholder")}
             />
           </div>
           <div className="w-full space-y-1.5 sm:w-32">
-            <Label>Max Concurrent</Label>
+            <Label>{t("links.maxConcurrent")}</Label>
             <Input
               type="number"
               min={1}
@@ -128,30 +130,30 @@ export function LinkCreateForm({ agentOptions, onSubmit }: LinkCreateFormProps)
           ) : (
             <ChevronRight className="h-3.5 w-3.5" />
           )}
-          Advanced Settings
+          {t("links.advancedSettings")}
         </button>
         {showAdvanced && (
           <div className="space-y-3 rounded-md border border-dashed p-3">
             <div className="space-y-1.5">
-              <Label>Allowed Users</Label>
+              <Label>{t("links.allowedUsers")}</Label>
               <Input
                 value={userAllow}
                 onChange={(e) => setUserAllow(e.target.value)}
-                placeholder="user1, user2, ..."
+                placeholder={t("links.allowedUsersPlaceholder")}
               />
               <p className="text-xs text-muted-foreground">
-                If set, only these users can trigger this delegation. Comma-separated.
+                {t("links.allowedUsersHint")}
               </p>
             </div>
             <div className="space-y-1.5">
-              <Label>Denied Users</Label>
+              <Label>{t("links.deniedUsers")}</Label>
               <Input
                 value={userDeny}
                 onChange={(e) => setUserDeny(e.target.value)}
-                placeholder="user3, user4, ..."
+                placeholder={t("links.deniedUsersPlaceholder")}
               />
               <p className="text-xs text-muted-foreground">
-                These users are blocked from triggering this delegation. Comma-separated.
+                {t("links.deniedUsersHint")}
               </p>
             </div>
           </div>
@@ -164,7 +166,7 @@ export function LinkCreateForm({ agentOptions, onSubmit }: LinkCreateFormProps)
             className="gap-1.5"
           >
             <Plus className="h-4 w-4" />
-            {creating ? "Creating..." : "Create Link"}
+            {creating ? t("links.creating") : t("links.createLink")}
           </Button>
         </div>
       </div>
diff --git a/ui/web/src/pages/agents/agent-detail/link-sections/link-edit-dialog.tsx b/ui/web/src/pages/agents/agent-detail/link-sections/link-edit-dialog.tsx
index 461258b8..c9a9761c 100644
--- a/ui/web/src/pages/agents/agent-detail/link-sections/link-edit-dialog.tsx
+++ b/ui/web/src/pages/agents/agent-detail/link-sections/link-edit-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -27,6 +28,7 @@ interface LinkEditDialogProps {
 }
 
 export function LinkEditDialog({ link, onClose, onSave }: LinkEditDialogProps) {
+  const { t } = useTranslation("agents");
   const [direction, setDirection] = useState("outbound");
   const [description, setDescription] = useState("");
   const [maxConcurrent, setMaxConcurrent] = useState("3");
@@ -66,14 +68,14 @@ export function LinkEditDialog({ link, onClose, onSave }: LinkEditDialogProps) {
     <Dialog open={!!link} onOpenChange={(open) => !open && onClose()}>
       <DialogContent>
         <DialogHeader>
-          <DialogTitle>Edit Link</DialogTitle>
+          <DialogTitle>{t("links.editTitle")}</DialogTitle>
           <DialogDescription>
-            Update the delegation link settings.
+            {t("links.editDescription")}
           </DialogDescription>
         </DialogHeader>
         <div className="space-y-4 py-2">
           <div className="space-y-1.5">
-            <Label>Direction</Label>
+            <Label>{t("links.direction")}</Label>
             <Select value={direction} onValueChange={setDirection}>
               <SelectTrigger>
                 <SelectValue />
@@ -91,15 +93,15 @@ export function LinkEditDialog({ link, onClose, onSave }: LinkEditDialogProps) {
             </p>
           </div>
           <div className="space-y-1.5">
-            <Label>Description</Label>
+            <Label>{t("links.description")}</Label>
             <Input
               value={description}
               onChange={(e) => setDescription(e.target.value)}
-              placeholder="Optional description..."
+              placeholder={t("links.optionalDescription")}
             />
           </div>
           <div className="space-y-1.5">
-            <Label>Max Concurrent</Label>
+            <Label>{t("links.maxConcurrent")}</Label>
             <Input
               type="number"
               min={1}
@@ -108,34 +110,34 @@ export function LinkEditDialog({ link, onClose, onSave }: LinkEditDialogProps) {
             />
           </div>
           <div className="space-y-1.5">
-            <Label>Allowed Users</Label>
+            <Label>{t("links.allowedUsers")}</Label>
             <Input
               value={userAllow}
               onChange={(e) => setUserAllow(e.target.value)}
               placeholder="user1, user2, ..."
             />
             <p className="text-xs text-muted-foreground">
-              If set, only these users can trigger this delegation.
+              {t("links.allowedUsersHintShort")}
             </p>
           </div>
           <div className="space-y-1.5">
-            <Label>Denied Users</Label>
+            <Label>{t("links.deniedUsers")}</Label>
             <Input
               value={userDeny}
               onChange={(e) => setUserDeny(e.target.value)}
               placeholder="user3, user4, ..."
             />
             <p className="text-xs text-muted-foreground">
-              These users are blocked from triggering this delegation.
+              {t("links.deniedUsersHintShort")}
             </p>
           </div>
         </div>
         <DialogFooter>
           <Button variant="outline" onClick={onClose} disabled={saving}>
-            Cancel
+            {t("files.cancel")}
           </Button>
           <Button onClick={handleSave} disabled={saving}>
-            {saving ? "Saving..." : "Save"}
+            {saving ? t("config.saving") : t("general.saveChanges")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/agents/agent-detail/link-sections/link-list.tsx b/ui/web/src/pages/agents/agent-detail/link-sections/link-list.tsx
index 5a4014a1..86d26982 100644
--- a/ui/web/src/pages/agents/agent-detail/link-sections/link-list.tsx
+++ b/ui/web/src/pages/agents/agent-detail/link-sections/link-list.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Link2, Pencil, Trash2, Users } from "lucide-react";
 import { Link } from "react-router";
 import { Button } from "@/components/ui/button";
@@ -23,10 +24,12 @@ export function LinkList({
   onEdit,
   onDelete,
 }: LinkListProps) {
+  const { t } = useTranslation("agents");
+
   if (loading && links.length === 0) {
     return (
       <div className="py-8 text-center text-sm text-muted-foreground">
-        Loading links...
+        {t("links.loadingLinks")}
       </div>
     );
   }
@@ -35,9 +38,9 @@ export function LinkList({
     return (
       <div className="flex flex-col items-center gap-2 py-8 text-center">
         <Link2 className="h-8 w-8 text-muted-foreground/50" />
-        <p className="text-sm text-muted-foreground">No agent links yet</p>
+        <p className="text-sm text-muted-foreground">{t("links.noLinks")}</p>
         <p className="text-xs text-muted-foreground">
-          Create links to allow agents to delegate tasks to each other.
+          {t("links.noLinksDesc")}
         </p>
       </div>
     );
@@ -46,10 +49,10 @@ export function LinkList({
   return (
     <div className="overflow-x-auto rounded-lg border">
       <div className="grid min-w-[500px] grid-cols-[1fr_100px_60px_60px_80px] items-center gap-2 border-b bg-muted/50 px-4 py-2.5 text-xs font-medium text-muted-foreground">
-        <span>Target</span>
-        <span>Direction</span>
-        <span>Status</span>
-        <span>Limit</span>
+        <span>{t("links.columns.target")}</span>
+        <span>{t("links.columns.direction")}</span>
+        <span>{t("links.columns.status")}</span>
+        <span>{t("links.columns.limit")}</span>
         <span />
       </div>
       {links.map((link) => (
diff --git a/ui/web/src/pages/agents/agents-page.tsx b/ui/web/src/pages/agents/agents-page.tsx
index 2c18911d..641e3985 100644
--- a/ui/web/src/pages/agents/agents-page.tsx
+++ b/ui/web/src/pages/agents/agents-page.tsx
@@ -1,6 +1,7 @@
 import { useState, useEffect } from "react";
 import { useParams, useNavigate } from "react-router";
 import { Plus, Bot } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { PageHeader } from "@/components/shared/page-header";
 import { EmptyState } from "@/components/shared/empty-state";
 import { SearchInput } from "@/components/shared/search-input";
@@ -18,6 +19,7 @@ import { SummoningModal } from "./summoning-modal";
 import { usePagination } from "@/hooks/use-pagination";
 
 export function AgentsPage() {
+  const { t } = useTranslation("agents");
   const { id: detailId } = useParams<{ id: string }>();
   const navigate = useNavigate();
   const { agents, loading, createAgent, deleteAgent, refresh, resummonAgent } = useAgents();
@@ -62,11 +64,11 @@ export function AgentsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Agents"
-        description="Manage your AI agents"
+        title={t("title")}
+        description={t("description")}
         actions={
           <Button onClick={() => setCreateOpen(true)} className="gap-1">
-            <Plus className="h-4 w-4" /> Create Agent
+            <Plus className="h-4 w-4" /> {t("createAgent")}
           </Button>
         }
       />
@@ -75,7 +77,7 @@ export function AgentsPage() {
         <SearchInput
           value={search}
           onChange={setSearch}
-          placeholder="Search agents..."
+          placeholder={t("searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -90,11 +92,11 @@ export function AgentsPage() {
         ) : filtered.length === 0 ? (
           <EmptyState
             icon={Bot}
-            title={search ? "No matching agents" : "No agents yet"}
+            title={search ? t("noMatchTitle") : t("emptyTitle")}
             description={
               search
-                ? "Try a different search term."
-                : "Create your first agent to get started."
+                ? t("noMatchDescription")
+                : t("emptyDescription")
             }
           />
         ) : (
@@ -152,9 +154,9 @@ export function AgentsPage() {
       <ConfirmDialog
         open={!!deleteTarget}
         onOpenChange={() => setDeleteTarget(null)}
-        title="Delete Agent"
-        description="Are you sure you want to delete this agent? This action cannot be undone."
-        confirmLabel="Delete"
+        title={t("delete.title")}
+        description={t("delete.description")}
+        confirmLabel={t("delete.confirmLabel")}
         variant="destructive"
         onConfirm={async () => {
           if (deleteTarget) {
diff --git a/ui/web/src/pages/agents/summoning-modal.tsx b/ui/web/src/pages/agents/summoning-modal.tsx
index bcc84d39..a336505b 100644
--- a/ui/web/src/pages/agents/summoning-modal.tsx
+++ b/ui/web/src/pages/agents/summoning-modal.tsx
@@ -1,5 +1,6 @@
 import { useCallback, useEffect, useState } from "react";
 import { motion, AnimatePresence } from "framer-motion";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -36,6 +37,7 @@ export function SummoningModal({
   hideClose = false,
   onContinue,
 }: SummoningModalProps) {
+  const { t } = useTranslation("agents");
   const [generatedFiles, setGeneratedFiles] = useState<string[]>([]);
   const [status, setStatus] = useState<"summoning" | "completed" | "failed">("summoning");
   const [errorMsg, setErrorMsg] = useState("");
@@ -71,11 +73,11 @@ export function SummoningModal({
       }
       if (data.type === "failed") {
         setStatus("failed");
-        setErrorMsg(data.error || "Summoning failed");
+        setErrorMsg(data.error || t("summoning.failed"));
         onCompleted();
       }
     },
-    [agentId, onCompleted],
+    [agentId, onCompleted, t],
   );
 
   useWsEvent("agent.summoning", handleSummoningEvent);
@@ -100,10 +102,10 @@ export function SummoningModal({
         <DialogHeader>
           <DialogTitle className="text-center">
             {status === "completed"
-              ? "Summoning Complete!"
+              ? t("summoning.completed")
               : status === "failed"
-                ? "Summoning Failed"
-                : "Summoning Your Agent..."}
+                ? t("summoning.failed")
+                : t("summoning.title")}
           </DialogTitle>
         </DialogHeader>
 
@@ -153,14 +155,14 @@ export function SummoningModal({
           <p className="text-sm text-foreground">
             {status === "completed" ? (
               <span className="font-medium text-emerald-600 dark:text-emerald-400">
-                {agentName} is ready!
+                {t("summoning.agentReady", { name: agentName })}
               </span>
             ) : status === "failed" ? (
               <span className="font-medium text-red-600 dark:text-red-400">
-                {errorMsg || "Using template files as fallback."}
+                {errorMsg || t("summoning.failed")}
               </span>
             ) : (
-              <>Weaving the soul of <span className="font-semibold text-foreground">{agentName}</span>...</>
+              <>{t("summoning.weavingSoul")} <span className="font-semibold text-foreground">{agentName}</span>...</>
             )}
           </p>
 
@@ -200,7 +202,7 @@ export function SummoningModal({
                         animate={{ opacity: 1, scale: 1 }}
                         className="text-xs text-violet-600 dark:text-violet-400"
                       >
-                        done
+                        {t("summoning.done")}
                       </motion.span>
                     )}
                   </motion.div>
@@ -211,19 +213,19 @@ export function SummoningModal({
 
           {status === "summoning" && (
             <p className="text-center text-xs text-muted-foreground">
-              This usually takes few minutes. Please wait...
+              {t("summoning.wait")}
             </p>
           )}
 
           {status === "completed" && onContinue && (
             <Button size="sm" onClick={onContinue}>
-              Continue
+              {t("summoning.continue")}
             </Button>
           )}
 
           {status === "failed" && (
             <Button variant="outline" size="sm" onClick={handleRetry} disabled={retrying}>
-              {retrying ? "Retrying..." : "Retry"}
+              {retrying ? t("summoning.retrying") : t("summoning.retry")}
             </Button>
           )}
         </div>
diff --git a/ui/web/src/pages/approvals/approvals-page.tsx b/ui/web/src/pages/approvals/approvals-page.tsx
index 3ff8c8ae..ac494ed2 100644
--- a/ui/web/src/pages/approvals/approvals-page.tsx
+++ b/ui/web/src/pages/approvals/approvals-page.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { ShieldCheck, Check, X, RefreshCw } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -12,6 +13,8 @@ import { useMinLoading } from "@/hooks/use-min-loading";
 import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 
 export function ApprovalsPage() {
+  const { t } = useTranslation("approvals");
+  const { t: tc } = useTranslation("common");
   const { pending, loading, refresh, approve, deny } = useApprovals();
   const spinning = useMinLoading(loading);
   const showSkeleton = useDeferredLoading(loading && pending.length === 0);
@@ -21,15 +24,15 @@ export function ApprovalsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Approvals"
-        description="Pending execution approvals"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex items-center gap-2">
             {pending.length > 0 && (
-              <Badge variant="destructive">{pending.length} pending</Badge>
+              <Badge variant="destructive">{t("pending", { count: pending.length })}</Badge>
             )}
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
             </Button>
           </div>
         }
@@ -41,8 +44,8 @@ export function ApprovalsPage() {
         ) : pending.length === 0 ? (
           <EmptyState
             icon={ShieldCheck}
-            title="No pending approvals"
-            description="All execution requests have been resolved. New requests will appear here in real-time."
+            title={t("emptyTitle")}
+            description={t("emptyDescription")}
           />
         ) : (
           <div className="space-y-3">
@@ -66,7 +69,7 @@ export function ApprovalsPage() {
                       onClick={() => setApproveTarget({ approval, always: false })}
                       className="gap-1"
                     >
-                      <Check className="h-3.5 w-3.5" /> Allow Once
+                      <Check className="h-3.5 w-3.5" /> {t("allowOnce")}
                     </Button>
                     <Button
                       variant="outline"
@@ -74,7 +77,7 @@ export function ApprovalsPage() {
                       onClick={() => setApproveTarget({ approval, always: true })}
                       className="gap-1"
                     >
-                      <Check className="h-3.5 w-3.5" /> Allow Always
+                      <Check className="h-3.5 w-3.5" /> {t("allowAlways")}
                     </Button>
                     <Button
                       variant="destructive"
@@ -82,7 +85,7 @@ export function ApprovalsPage() {
                       onClick={() => setDenyTarget(approval)}
                       className="gap-1"
                     >
-                      <X className="h-3.5 w-3.5" /> Deny
+                      <X className="h-3.5 w-3.5" /> {t("deny")}
                     </Button>
                   </div>
                 </div>
@@ -95,13 +98,13 @@ export function ApprovalsPage() {
       <ConfirmDialog
         open={!!approveTarget}
         onOpenChange={() => setApproveTarget(null)}
-        title={approveTarget?.always ? "Allow Always" : "Allow Once"}
+        title={approveTarget?.always ? t("confirmAllowAlways.title") : t("confirmAllowOnce.title")}
         description={
           approveTarget?.always
-            ? `Permanently allow "${approveTarget.approval.command}" for agent "${approveTarget.approval.agentId}"? This command will be auto-approved in the future.`
-            : `Allow execution of "${approveTarget?.approval.command}" from agent "${approveTarget?.approval.agentId}"?`
+            ? t("confirmAllowAlways.description", { command: approveTarget.approval.command, agentId: approveTarget.approval.agentId })
+            : t("confirmAllowOnce.description", { command: approveTarget?.approval.command, agentId: approveTarget?.approval.agentId })
         }
-        confirmLabel={approveTarget?.always ? "Allow Always" : "Allow Once"}
+        confirmLabel={approveTarget?.always ? t("allowAlways") : t("allowOnce")}
         onConfirm={async () => {
           if (approveTarget) {
             await approve(approveTarget.approval.id, approveTarget.always);
@@ -113,9 +116,9 @@ export function ApprovalsPage() {
       <ConfirmDialog
         open={!!denyTarget}
         onOpenChange={() => setDenyTarget(null)}
-        title="Deny Execution"
-        description={`Deny execution request "${denyTarget?.command}" from agent "${denyTarget?.agentId}"?`}
-        confirmLabel="Deny"
+        title={t("confirmDeny.title")}
+        description={t("confirmDeny.description", { command: denyTarget?.command, agentId: denyTarget?.agentId })}
+        confirmLabel={t("confirmDeny.confirmLabel")}
         variant="destructive"
         onConfirm={async () => {
           if (denyTarget) {
diff --git a/ui/web/src/pages/builtin-tools/builtin-tool-settings-dialog.tsx b/ui/web/src/pages/builtin-tools/builtin-tool-settings-dialog.tsx
index 00afa911..ea1f987c 100644
--- a/ui/web/src/pages/builtin-tools/builtin-tool-settings-dialog.tsx
+++ b/ui/web/src/pages/builtin-tools/builtin-tool-settings-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -62,6 +63,7 @@ function JsonSettingsForm({
   onOpenChange: (open: boolean) => void;
   onSave: (name: string, settings: Record<string, unknown>) => Promise<void>;
 }) {
+  const { t } = useTranslation("tools");
   const [json, setJson] = useState("");
   const [error, setError] = useState("");
   const [saving, setSaving] = useState(false);
@@ -93,7 +95,7 @@ function JsonSettingsForm({
       setError("");
       setValidJson(true);
     } catch {
-      setError("Cannot format: invalid JSON");
+      setError(t("builtin.jsonDialog.cannotFormat"));
     }
   };
 
@@ -106,7 +108,7 @@ function JsonSettingsForm({
       await onSave(tool.name, parsed);
       onOpenChange(false);
     } catch (e) {
-      setError(e instanceof SyntaxError ? "Invalid JSON" : String(e));
+      setError(e instanceof SyntaxError ? t("builtin.jsonDialog.invalidJson") : String(e));
     } finally {
       setSaving(false);
     }
@@ -115,9 +117,9 @@ function JsonSettingsForm({
   return (
     <>
       <DialogHeader>
-        <DialogTitle>Settings: {tool?.display_name ?? tool?.name}</DialogTitle>
+        <DialogTitle>{t("builtin.jsonDialog.title", { name: tool?.display_name ?? tool?.name })}</DialogTitle>
         <DialogDescription>
-          Edit tool-specific settings as JSON. Changes take effect immediately after saving.
+          {t("builtin.jsonDialog.description")}
         </DialogDescription>
       </DialogHeader>
       <div className="space-y-3">
@@ -129,18 +131,18 @@ function JsonSettingsForm({
         />
         <div className="flex items-center justify-between">
           <Button variant="ghost" size="sm" onClick={handleFormat} className="h-7 px-2 text-xs">
-            Format JSON
+            {t("builtin.jsonDialog.formatJson")}
           </Button>
-          {!validJson && <span className="text-xs text-destructive">Invalid JSON syntax</span>}
+          {!validJson && <span className="text-xs text-destructive">{t("builtin.jsonDialog.invalidJsonSyntax")}</span>}
         </div>
         {error && <p className="text-sm text-destructive">{error}</p>}
       </div>
       <DialogFooter>
         <Button variant="outline" onClick={() => onOpenChange(false)}>
-          Cancel
+          {t("builtin.jsonDialog.cancel")}
         </Button>
         <Button onClick={handleSave} disabled={saving || !validJson}>
-          {saving ? "Saving..." : "Save"}
+          {saving ? t("builtin.jsonDialog.saving") : t("builtin.jsonDialog.save")}
         </Button>
       </DialogFooter>
     </>
diff --git a/ui/web/src/pages/builtin-tools/builtin-tools-page.tsx b/ui/web/src/pages/builtin-tools/builtin-tools-page.tsx
index b49ee464..537b1323 100644
--- a/ui/web/src/pages/builtin-tools/builtin-tools-page.tsx
+++ b/ui/web/src/pages/builtin-tools/builtin-tools-page.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Package, RefreshCw, Settings, Info } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -20,23 +21,10 @@ import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 
 /* eslint-disable @typescript-eslint/no-explicit-any */
 
-const CATEGORY_LABELS: Record<string, string> = {
-  filesystem: "Filesystem",
-  runtime: "Runtime",
-  web: "Web",
-  memory: "Memory",
-  media: "Media",
-  browser: "Browser",
-  sessions: "Sessions",
-  messaging: "Messaging",
-  scheduling: "Scheduling",
-  subagents: "Agents",
-  skills: "Skills",
-  delegation: "Delegation",
-  teams: "Teams",
-};
-
-const CATEGORY_ORDER = Object.keys(CATEGORY_LABELS);
+const CATEGORY_ORDER = [
+  "filesystem", "runtime", "web", "memory", "media", "browser",
+  "sessions", "messaging", "scheduling", "subagents", "skills", "delegation", "teams",
+];
 
 function hasEditableSettings(tool: BuiltinToolData): boolean {
   return tool.settings != null && Object.keys(tool.settings).length > 0;
@@ -47,6 +35,7 @@ function getConfigHint(tool: BuiltinToolData): string | undefined {
 }
 
 export function BuiltinToolsPage() {
+  const { t } = useTranslation("tools");
   const { tools, loading, refresh, updateTool } = useBuiltinTools();
   const spinning = useMinLoading(loading);
   const showSkeleton = useDeferredLoading(loading && tools.length === 0);
@@ -81,8 +70,8 @@ export function BuiltinToolsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Built-in Tools"
-        description="Manage system built-in tools. Enable/disable or configure settings globally."
+        title={t("builtin.title")}
+        description={t("builtin.description")}
         actions={
           <Button
             variant="outline"
@@ -92,7 +81,7 @@ export function BuiltinToolsPage() {
             className="gap-1"
           >
             <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} />
-            Refresh
+            {t("common:refresh", "Refresh")}
           </Button>
         }
       />
@@ -101,12 +90,14 @@ export function BuiltinToolsPage() {
         <SearchInput
           value={search}
           onChange={setSearch}
-          placeholder="Search tools..."
+          placeholder={t("builtin.searchPlaceholder")}
           className="max-w-sm"
         />
         <span className="text-xs text-muted-foreground">
-          {filtered.length} tool{filtered.length !== 1 ? "s" : ""}
-          {sortedCategories.length > 0 && ` · ${sortedCategories.length} categories`}
+          {filtered.length !== 1
+            ? t("builtin.toolCountPlural", { count: filtered.length })
+            : t("builtin.toolCount", { count: filtered.length })}
+          {sortedCategories.length > 0 && ` · ${t("builtin.categoryCount", { count: sortedCategories.length })}`}
         </span>
       </div>
 
@@ -116,9 +107,9 @@ export function BuiltinToolsPage() {
         ) : filtered.length === 0 ? (
           <EmptyState
             icon={Package}
-            title={search ? "No matching tools" : "No built-in tools"}
+            title={search ? t("builtin.noMatchTitle") : t("builtin.emptyTitle")}
             description={
-              search ? "Try a different search term." : "No built-in tools have been seeded yet."
+              search ? t("builtin.noMatchDescription") : t("builtin.emptyDescription")
             }
           />
         ) : (
@@ -157,10 +148,11 @@ function CategoryGroup({
   onToggle: (tool: BuiltinToolData) => void;
   onSettings: (tool: BuiltinToolData) => void;
 }) {
+  const { t } = useTranslation("tools");
   return (
     <div className="rounded-lg border">
       <div className="flex items-center gap-2 border-b bg-muted/40 px-4 py-2">
-        <span className="text-sm font-medium">{CATEGORY_LABELS[category] ?? category}</span>
+        <span className="text-sm font-medium">{t(`builtin.categories.${category}`, category)}</span>
         <Badge variant="secondary" className="h-5 px-1.5 text-[11px]">
           {tools.length}
         </Badge>
@@ -183,6 +175,7 @@ function ToolRow({
   onToggle: (tool: BuiltinToolData) => void;
   onSettings: (tool: BuiltinToolData) => void;
 }) {
+  const { t } = useTranslation("tools");
   const configHint = getConfigHint(tool);
   const editable = hasEditableSettings(tool);
 
@@ -197,11 +190,11 @@ function ToolRow({
               <Tooltip>
                 <TooltipTrigger asChild>
                   <Badge variant="outline" className="ml-1 h-4 px-1 text-[10px] leading-none cursor-default">
-                    req
+                    {t("builtin.requires")}
                   </Badge>
                 </TooltipTrigger>
                 <TooltipContent side="top">
-                  <p className="text-xs">Requires: {tool.requires.join(", ")}</p>
+                  <p className="text-xs">{t("builtin.requiresTooltip", { list: tool.requires.join(", ") })}</p>
                 </TooltipContent>
               </Tooltip>
             </TooltipProvider>
@@ -223,7 +216,7 @@ function ToolRow({
             className="h-7 gap-1 px-2 text-xs"
           >
             <Settings className="h-3 w-3" />
-            Settings
+            {t("builtin.settings")}
           </Button>
         )}
         {!editable && configHint && (
@@ -236,7 +229,7 @@ function ToolRow({
                 </span>
               </TooltipTrigger>
               <TooltipContent side="top">
-                <p className="text-xs">Configured via the Config page</p>
+                <p className="text-xs">{t("builtin.configuredVia")}</p>
               </TooltipContent>
             </Tooltip>
           </TooltipProvider>
diff --git a/ui/web/src/pages/builtin-tools/kg-settings-form.tsx b/ui/web/src/pages/builtin-tools/kg-settings-form.tsx
index 963d898f..39b4bbe6 100644
--- a/ui/web/src/pages/builtin-tools/kg-settings-form.tsx
+++ b/ui/web/src/pages/builtin-tools/kg-settings-form.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   DialogHeader,
   DialogTitle,
@@ -32,6 +33,7 @@ interface Props {
 }
 
 export function KGSettingsForm({ initialSettings, onSave, onCancel }: Props) {
+  const { t } = useTranslation("tools");
   const [settings, setSettings] = useState<KGSettings>(defaultSettings);
   const [saving, setSaving] = useState(false);
 
@@ -55,9 +57,9 @@ export function KGSettingsForm({ initialSettings, onSave, onCancel }: Props) {
   return (
     <>
       <DialogHeader>
-        <DialogTitle>Knowledge Graph Settings</DialogTitle>
+        <DialogTitle>{t("builtin.kgSettings.title")}</DialogTitle>
         <DialogDescription>
-          Configure entity extraction from memory writes. Requires a provider/model capable of structured JSON output.
+          {t("builtin.kgSettings.description")}
         </DialogDescription>
       </DialogHeader>
 
@@ -67,14 +69,14 @@ export function KGSettingsForm({ initialSettings, onSave, onCancel }: Props) {
           onProviderChange={(v) => setSettings((s) => ({ ...s, extraction_provider: v }))}
           model={settings.extraction_model}
           onModelChange={(v) => setSettings((s) => ({ ...s, extraction_model: v }))}
-          providerLabel="Extraction Provider"
-          modelLabel="Extraction Model"
-          providerTip="LLM provider used to extract entities and relations from text."
-          modelTip="Model ID for extraction. Should support structured JSON output."
+          providerLabel={t("builtin.kgSettings.extractionProvider")}
+          modelLabel={t("builtin.kgSettings.extractionModel")}
+          providerTip={t("builtin.kgSettings.providerTip")}
+          modelTip={t("builtin.kgSettings.modelTip")}
         />
 
         <div className="grid gap-1.5">
-          <Label htmlFor="kg-min-conf" className="text-sm">Min Confidence</Label>
+          <Label htmlFor="kg-min-conf" className="text-sm">{t("builtin.kgSettings.minConfidence")}</Label>
           <Input
             id="kg-min-conf"
             type="number"
@@ -86,15 +88,15 @@ export function KGSettingsForm({ initialSettings, onSave, onCancel }: Props) {
             className="max-w-[120px]"
           />
           <p className="text-xs text-muted-foreground">
-            Entities below this confidence score are discarded (0.0–1.0).
+            {t("builtin.kgSettings.minConfidenceHint")}
           </p>
         </div>
 
         <div className="flex items-center justify-between rounded-md border p-3">
           <div>
-            <Label htmlFor="kg-auto-extract" className="text-sm font-medium">Auto-extract on memory write</Label>
+            <Label htmlFor="kg-auto-extract" className="text-sm font-medium">{t("builtin.kgSettings.autoExtract")}</Label>
             <p className="text-xs text-muted-foreground mt-0.5">
-              Automatically extract entities when agents write to memory files.
+              {t("builtin.kgSettings.autoExtractHint")}
             </p>
           </div>
           <Switch
@@ -106,9 +108,9 @@ export function KGSettingsForm({ initialSettings, onSave, onCancel }: Props) {
       </div>
 
       <DialogFooter>
-        <Button variant="outline" onClick={onCancel}>Cancel</Button>
+        <Button variant="outline" onClick={onCancel}>{t("builtin.kgSettings.cancel")}</Button>
         <Button onClick={handleSave} disabled={saving}>
-          {saving ? "Saving..." : "Save"}
+          {saving ? t("builtin.kgSettings.saving") : t("builtin.kgSettings.save")}
         </Button>
       </DialogFooter>
     </>
diff --git a/ui/web/src/pages/builtin-tools/media-provider-chain-form.tsx b/ui/web/src/pages/builtin-tools/media-provider-chain-form.tsx
index 1c968b83..2c8a9477 100644
--- a/ui/web/src/pages/builtin-tools/media-provider-chain-form.tsx
+++ b/ui/web/src/pages/builtin-tools/media-provider-chain-form.tsx
@@ -1,4 +1,5 @@
 import { useState, useCallback, useRef } from "react";
+import { useTranslation } from "react-i18next";
 import {
   DndContext,
   closestCenter,
@@ -121,6 +122,7 @@ interface SortableCardProps {
 }
 
 function SortableProviderCard({ entry, index, toolName, enabledProviders, onUpdate, onRemove, portalRef }: SortableCardProps) {
+  const { t } = useTranslation("tools");
   const [expanded, setExpanded] = useState(false);
   const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({
     id: entry.id,
@@ -186,7 +188,7 @@ function SortableProviderCard({ entry, index, toolName, enabledProviders, onUpda
         />
 
         <span className="text-sm font-medium truncate">
-          {selectedProvider?.display_name || entry.provider || "New Provider"}
+          {selectedProvider?.display_name || entry.provider || t("builtin.mediaChain.newProvider")}
         </span>
 
         <Button
@@ -203,10 +205,10 @@ function SortableProviderCard({ entry, index, toolName, enabledProviders, onUpda
       {/* Row 2: provider + model selects */}
       <div className="grid grid-cols-2 gap-2 px-3 py-1.5">
         <div className="space-y-1">
-          <Label className="text-xs text-muted-foreground">Provider</Label>
+          <Label className="text-xs text-muted-foreground">{t("builtin.mediaChain.provider")}</Label>
           <Select value={entry.provider} onValueChange={handleProviderChange}>
             <SelectTrigger className="h-8 text-sm">
-              <SelectValue placeholder="Select provider" />
+              <SelectValue placeholder={t("builtin.mediaChain.selectProvider")} />
             </SelectTrigger>
             <SelectContent>
               {enabledProviders.map((p) => (
@@ -218,12 +220,12 @@ function SortableProviderCard({ entry, index, toolName, enabledProviders, onUpda
           </Select>
         </div>
         <div className="space-y-1">
-          <Label className="text-xs text-muted-foreground">Model</Label>
+          <Label className="text-xs text-muted-foreground">{t("builtin.mediaChain.model")}</Label>
           <Combobox
             value={entry.model}
             onChange={(v) => onUpdate(entry.id, { model: v })}
             options={models.map((m) => ({ value: m.id, label: m.name ?? m.id }))}
-            placeholder={modelsLoading ? "Loading..." : "Select model"}
+            placeholder={modelsLoading ? t("builtin.mediaChain.loadingModels") : t("builtin.mediaChain.selectModel")}
             className="h-8 text-sm"
             portalContainer={portalRef}
           />
@@ -233,7 +235,7 @@ function SortableProviderCard({ entry, index, toolName, enabledProviders, onUpda
       {/* Row 3: timeout, retries, expand button */}
       <div className="flex items-center gap-3 px-3 pb-3 pt-1">
         <div className="flex items-center gap-1.5">
-          <Label className="text-xs text-muted-foreground whitespace-nowrap">Timeout</Label>
+          <Label className="text-xs text-muted-foreground whitespace-nowrap">{t("builtin.mediaChain.timeout")}</Label>
           <div className="relative">
             <Input
               type="number"
@@ -247,7 +249,7 @@ function SortableProviderCard({ entry, index, toolName, enabledProviders, onUpda
           </div>
         </div>
         <div className="flex items-center gap-1.5">
-          <Label className="text-xs text-muted-foreground whitespace-nowrap">Retries</Label>
+          <Label className="text-xs text-muted-foreground whitespace-nowrap">{t("builtin.mediaChain.retries")}</Label>
           <Input
             type="number"
             min={0}
@@ -264,7 +266,7 @@ function SortableProviderCard({ entry, index, toolName, enabledProviders, onUpda
             onClick={() => setExpanded((v) => !v)}
             className="ml-auto flex items-center gap-1 text-xs text-muted-foreground hover:text-foreground"
           >
-            Settings
+            {t("builtin.mediaChain.settings")}
             {expanded ? <ChevronUp className="size-3" /> : <ChevronDown className="size-3" />}
           </button>
         )}
@@ -358,6 +360,7 @@ export function MediaProviderChainForm({
   onSave,
   onCancel,
 }: MediaProviderChainFormProps) {
+  const { t } = useTranslation("tools");
   const { providers } = useProviders();
   const enabledProviders = providers.filter((p) => p.enabled);
   const portalRef = useRef<HTMLDivElement | null>(null);
@@ -420,9 +423,9 @@ export function MediaProviderChainForm({
   return (
     <div ref={portalRef} className="relative">
       <DialogHeader>
-        <DialogTitle>{formatToolTitle(toolName)} — Provider Chain</DialogTitle>
+        <DialogTitle>{formatToolTitle(toolName)} {t("builtin.mediaChain.providerChainSuffix")}</DialogTitle>
         <DialogDescription>
-          Configure and order provider fallbacks. Drag to reorder — the first enabled provider is tried first.
+          {t("builtin.mediaChain.description")}
         </DialogDescription>
       </DialogHeader>
 
@@ -446,22 +449,22 @@ export function MediaProviderChainForm({
 
         {entries.length === 0 && (
           <p className="text-sm text-muted-foreground text-center py-6">
-            No providers configured. Add one below.
+            {t("builtin.mediaChain.noProviders")}
           </p>
         )}
 
         <Button type="button" variant="outline" size="sm" className="w-full" onClick={handleAdd}>
           <Plus className="size-3.5 mr-1.5" />
-          Add Provider
+          {t("builtin.mediaChain.addProvider")}
         </Button>
       </div>
 
       <DialogFooter>
         <Button variant="outline" onClick={onCancel}>
-          Cancel
+          {t("builtin.mediaChain.cancel")}
         </Button>
         <Button onClick={handleSave} disabled={saving}>
-          {saving ? "Saving..." : "Save"}
+          {saving ? t("builtin.mediaChain.saving") : t("builtin.mediaChain.save")}
         </Button>
       </DialogFooter>
     </div>
diff --git a/ui/web/src/pages/channels/channel-detail/channel-config-tab.tsx b/ui/web/src/pages/channels/channel-detail/channel-config-tab.tsx
index 2f7c5bed..db3484a4 100644
--- a/ui/web/src/pages/channels/channel-detail/channel-config-tab.tsx
+++ b/ui/web/src/pages/channels/channel-detail/channel-config-tab.tsx
@@ -1,4 +1,5 @@
 import { useState, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Save, Check, AlertCircle } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import type { ChannelInstanceData } from "@/types/channel";
@@ -11,6 +12,7 @@ interface ChannelConfigTabProps {
 }
 
 export function ChannelConfigTab({ instance, onUpdate }: ChannelConfigTabProps) {
+  const { t } = useTranslation("channels");
   const config = instance.config ?? {};
   // Filter out "groups" from config — managed in separate Groups tab
   const { groups: _groups, ...restConfig } = config as Record<string, unknown> & { groups?: unknown };
@@ -54,7 +56,7 @@ export function ChannelConfigTab({ instance, onUpdate }: ChannelConfigTabProps)
     return (
       <div className="max-w-2xl">
         <p className="text-sm text-muted-foreground">
-          No configuration schema for this channel type.
+          {t("detail.config.noSchema")}
         </p>
       </div>
     );
@@ -78,12 +80,12 @@ export function ChannelConfigTab({ instance, onUpdate }: ChannelConfigTabProps)
       <div className="flex items-center justify-end gap-2">
         {saved && (
           <span className="flex items-center gap-1 text-sm text-success">
-            <Check className="h-3.5 w-3.5" /> Saved
+            <Check className="h-3.5 w-3.5" /> {t("detail.config.saved")}
           </span>
         )}
         <Button onClick={handleSave} disabled={saving}>
           {!saving && <Save className="h-4 w-4" />}
-          {saving ? "Saving..." : "Save Config"}
+          {saving ? t("detail.config.saving") : t("detail.config.saveConfig")}
         </Button>
       </div>
     </div>
diff --git a/ui/web/src/pages/channels/channel-detail/channel-credentials-tab.tsx b/ui/web/src/pages/channels/channel-detail/channel-credentials-tab.tsx
index 7a92e09e..1263572b 100644
--- a/ui/web/src/pages/channels/channel-detail/channel-credentials-tab.tsx
+++ b/ui/web/src/pages/channels/channel-detail/channel-credentials-tab.tsx
@@ -4,6 +4,7 @@ import { Button } from "@/components/ui/button";
 import type { ChannelInstanceData } from "@/types/channel";
 import { credentialsSchema } from "../channel-schemas";
 import { ChannelFields } from "../channel-fields";
+import { useTranslation } from "react-i18next";
 
 interface ChannelCredentialsTabProps {
   instance: ChannelInstanceData;
@@ -11,6 +12,7 @@ interface ChannelCredentialsTabProps {
 }
 
 export function ChannelCredentialsTab({ instance, onUpdate }: ChannelCredentialsTabProps) {
+  const { t } = useTranslation("channels");
   const [values, setValues] = useState<Record<string, unknown>>({});
   const [saving, setSaving] = useState(false);
   const [saveError, setSaveError] = useState<string | null>(null);
@@ -27,7 +29,7 @@ export function ChannelCredentialsTab({ instance, onUpdate }: ChannelCredentials
       Object.entries(values).filter(([, v]) => v !== undefined && v !== "" && v !== null),
     );
     if (Object.keys(cleanCreds).length === 0) {
-      setSaveError("No credentials to update");
+      setSaveError(t("detail.credentials.noCredentials"));
       return;
     }
     setSaving(true);
@@ -39,7 +41,7 @@ export function ChannelCredentialsTab({ instance, onUpdate }: ChannelCredentials
       setValues({});
       setTimeout(() => setSaved(false), 3000);
     } catch (err) {
-      setSaveError(err instanceof Error ? err.message : "Failed to save");
+      setSaveError(err instanceof Error ? err.message : t("detail.credentials.failedSave"));
     } finally {
       setSaving(false);
     }
@@ -49,7 +51,7 @@ export function ChannelCredentialsTab({ instance, onUpdate }: ChannelCredentials
     return (
       <div className="max-w-2xl">
         <p className="text-sm text-muted-foreground">
-          No credentials schema for this channel type.
+          {t("detail.credentials.noSchema")}
         </p>
       </div>
     );
@@ -58,7 +60,7 @@ export function ChannelCredentialsTab({ instance, onUpdate }: ChannelCredentials
   return (
     <div className="max-w-2xl space-y-6">
       <p className="text-sm text-muted-foreground">
-        Leave fields blank to keep current values. Credentials are encrypted server-side and never returned in API responses.
+        {t("detail.credentials.hint")}
       </p>
 
       <ChannelFields
@@ -78,12 +80,12 @@ export function ChannelCredentialsTab({ instance, onUpdate }: ChannelCredentials
       <div className="flex items-center justify-end gap-2">
         {saved && (
           <span className="flex items-center gap-1 text-sm text-success">
-            <Check className="h-3.5 w-3.5" /> Saved
+            <Check className="h-3.5 w-3.5" /> {t("detail.credentials.saved")}
           </span>
         )}
         <Button onClick={handleSave} disabled={saving}>
           {!saving && <Save className="h-4 w-4" />}
-          {saving ? "Saving..." : "Update Credentials"}
+          {saving ? t("detail.credentials.saving") : t("detail.credentials.updateCredentials")}
         </Button>
       </div>
     </div>
diff --git a/ui/web/src/pages/channels/channel-detail/channel-detail-page.tsx b/ui/web/src/pages/channels/channel-detail/channel-detail-page.tsx
index ad73cf5b..06982289 100644
--- a/ui/web/src/pages/channels/channel-detail/channel-detail-page.tsx
+++ b/ui/web/src/pages/channels/channel-detail/channel-detail-page.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -20,6 +21,7 @@ interface ChannelDetailPageProps {
 }
 
 export function ChannelDetailPage({ instanceId, onBack }: ChannelDetailPageProps) {
+  const { t } = useTranslation("channels");
   const {
     instance,
     loading,
@@ -61,11 +63,11 @@ export function ChannelDetailPage({ instanceId, onBack }: ChannelDetailPageProps
               {instance.display_name || instance.name}
             </h2>
             <Badge variant={instance.enabled ? "success" : "secondary"}>
-              {instance.enabled ? "Enabled" : "Disabled"}
+              {instance.enabled ? t("enabled") : t("disabled")}
             </Badge>
             {status && (
               <Badge variant={status.running ? "success" : "secondary"}>
-                {status.running ? "Running" : "Stopped"}
+                {status.running ? t("status.running") : t("status.stopped")}
               </Badge>
             )}
           </div>
@@ -80,7 +82,7 @@ export function ChannelDetailPage({ instanceId, onBack }: ChannelDetailPageProps
               {channelTypeLabels[instance.channel_type] || instance.channel_type}
             </Badge>
             <span className="text-border">|</span>
-            <span>Agent: {agentName}</span>
+            <span>{t("detail.agent", { name: agentName })}</span>
           </div>
         </div>
       </div>
@@ -89,11 +91,11 @@ export function ChannelDetailPage({ instanceId, onBack }: ChannelDetailPageProps
       <div className="max-w-4xl rounded-xl border bg-card p-3 shadow-sm sm:p-4">
         <Tabs value={activeTab} onValueChange={setActiveTab}>
           <TabsList className="w-full justify-start overflow-x-auto overflow-y-hidden">
-            <TabsTrigger value="general">General</TabsTrigger>
-            <TabsTrigger value="credentials">Credentials</TabsTrigger>
-            <TabsTrigger value="config">Config</TabsTrigger>
-            {isTelegram && <TabsTrigger value="groups">Groups</TabsTrigger>}
-            <TabsTrigger value="writers">Writers</TabsTrigger>
+            <TabsTrigger value="general">{t("detail.tabs.general")}</TabsTrigger>
+            <TabsTrigger value="credentials">{t("detail.tabs.credentials")}</TabsTrigger>
+            <TabsTrigger value="config">{t("detail.tabs.config")}</TabsTrigger>
+            {isTelegram && <TabsTrigger value="groups">{t("detail.tabs.groups")}</TabsTrigger>}
+            <TabsTrigger value="writers">{t("detail.tabs.writers")}</TabsTrigger>
           </TabsList>
 
           <TabsContent value="general" className="mt-4">
diff --git a/ui/web/src/pages/channels/channel-detail/channel-general-tab.tsx b/ui/web/src/pages/channels/channel-detail/channel-general-tab.tsx
index 27b0740a..026c878f 100644
--- a/ui/web/src/pages/channels/channel-detail/channel-general-tab.tsx
+++ b/ui/web/src/pages/channels/channel-detail/channel-general-tab.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Save, Check, AlertCircle } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -22,6 +23,7 @@ interface ChannelGeneralTabProps {
 }
 
 export function ChannelGeneralTab({ instance, agents, onUpdate }: ChannelGeneralTabProps) {
+  const { t } = useTranslation("channels");
   const [displayName, setDisplayName] = useState(instance.display_name ?? "");
   const [agentId, setAgentId] = useState(instance.agent_id);
   const [enabled, setEnabled] = useState(instance.enabled);
@@ -53,32 +55,32 @@ export function ChannelGeneralTab({ instance, agents, onUpdate }: ChannelGeneral
     <div className="max-w-2xl space-y-6">
       {/* Read-only fields */}
       <div className="grid gap-1.5">
-        <Label>Name</Label>
+        <Label>{t("detail.general.name")}</Label>
         <Input value={instance.name} disabled />
-        <p className="text-xs text-muted-foreground">Unique slug (read-only)</p>
+        <p className="text-xs text-muted-foreground">{t("detail.general.nameHint")}</p>
       </div>
 
       <div className="grid gap-1.5">
-        <Label>Channel Type</Label>
+        <Label>{t("detail.general.channelType")}</Label>
         <Input value={channelTypeLabels[instance.channel_type] || instance.channel_type} disabled />
       </div>
 
       {/* Editable fields */}
       <div className="grid gap-1.5">
-        <Label htmlFor="cd-display">Display Name</Label>
+        <Label htmlFor="cd-display">{t("detail.general.displayName")}</Label>
         <Input
           id="cd-display"
           value={displayName}
           onChange={(e) => setDisplayName(e.target.value)}
-          placeholder="Friendly name"
+          placeholder={t("detail.general.displayNamePlaceholder")}
         />
       </div>
 
       <div className="grid gap-1.5">
-        <Label>Agent</Label>
+        <Label>{t("detail.general.agent")}</Label>
         <Select value={agentId} onValueChange={setAgentId}>
           <SelectTrigger>
-            <SelectValue placeholder="Select agent" />
+            <SelectValue placeholder={t("detail.general.selectAgent")} />
           </SelectTrigger>
           <SelectContent>
             {agents.map((a) => (
@@ -92,7 +94,7 @@ export function ChannelGeneralTab({ instance, agents, onUpdate }: ChannelGeneral
 
       <div className="flex items-center gap-2">
         <Switch id="cd-enabled" checked={enabled} onCheckedChange={setEnabled} />
-        <Label htmlFor="cd-enabled">Enabled</Label>
+        <Label htmlFor="cd-enabled">{t("detail.general.enabled")}</Label>
       </div>
 
       {/* Save */}
@@ -105,12 +107,12 @@ export function ChannelGeneralTab({ instance, agents, onUpdate }: ChannelGeneral
       <div className="flex items-center justify-end gap-2">
         {saved && (
           <span className="flex items-center gap-1 text-sm text-success">
-            <Check className="h-3.5 w-3.5" /> Saved
+            <Check className="h-3.5 w-3.5" /> {t("detail.general.saved")}
           </span>
         )}
         <Button onClick={handleSave} disabled={saving}>
           {!saving && <Save className="h-4 w-4" />}
-          {saving ? "Saving..." : "Save Changes"}
+          {saving ? t("detail.general.saving") : t("detail.general.saveChanges")}
         </Button>
       </div>
     </div>
diff --git a/ui/web/src/pages/channels/channel-detail/channel-groups-tab.tsx b/ui/web/src/pages/channels/channel-detail/channel-groups-tab.tsx
index fa27015e..edec255d 100644
--- a/ui/web/src/pages/channels/channel-detail/channel-groups-tab.tsx
+++ b/ui/web/src/pages/channels/channel-detail/channel-groups-tab.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Save, Check, AlertCircle } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import type { ChannelInstanceData } from "@/types/channel";
@@ -16,6 +17,7 @@ interface ChannelGroupsTabProps {
 }
 
 export function ChannelGroupsTab({ instance, onUpdate }: ChannelGroupsTabProps) {
+  const { t } = useTranslation("channels");
   const config = (instance.config ?? {}) as Record<string, unknown>;
   const [groups, setGroups] = useState<Record<string, GroupConfigWithTopics>>(
     (config.groups as Record<string, GroupConfigWithTopics>) ?? {},
@@ -59,12 +61,12 @@ export function ChannelGroupsTab({ instance, onUpdate }: ChannelGroupsTabProps)
       <div className="flex items-center justify-end gap-2">
         {saved && (
           <span className="flex items-center gap-1 text-sm text-success">
-            <Check className="h-3.5 w-3.5" /> Saved
+            <Check className="h-3.5 w-3.5" /> {t("detail.groups.saved")}
           </span>
         )}
         <Button onClick={handleSave} disabled={saving}>
           {!saving && <Save className="h-4 w-4" />}
-          {saving ? "Saving..." : "Save Groups"}
+          {saving ? t("detail.groups.saving") : t("detail.groups.saveGroups")}
         </Button>
       </div>
     </div>
diff --git a/ui/web/src/pages/channels/channel-detail/channel-writers-tab.tsx b/ui/web/src/pages/channels/channel-detail/channel-writers-tab.tsx
index 5c862adf..305b7ec0 100644
--- a/ui/web/src/pages/channels/channel-detail/channel-writers-tab.tsx
+++ b/ui/web/src/pages/channels/channel-detail/channel-writers-tab.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Plus, Trash2, RefreshCw, Users, ChevronDown, ChevronRight } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -25,6 +26,7 @@ export function ChannelWritersTab({
   addWriter,
   removeWriter,
 }: ChannelWritersTabProps) {
+  const { t } = useTranslation("channels");
   const [groups, setGroups] = useState<GroupWriterGroupInfo[]>([]);
   const [loadingGroups, setLoadingGroups] = useState(true);
 
@@ -97,7 +99,7 @@ export function ChannelWritersTab({
     const gid = targetGroupId || addGroupId.trim();
     const uid = addUserId.trim();
     if (!gid || !uid) {
-      setError("Group ID and User ID are required");
+      setError(t("detail.writers.addForm.errors.groupUserRequired"));
       return;
     }
     setAdding(true);
@@ -118,7 +120,7 @@ export function ChannelWritersTab({
         setExpanded((prev) => ({ ...prev, [gid]: true }));
       }
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to add writer");
+      setError(err instanceof Error ? err.message : t("detail.writers.addForm.errors.failedAdd"));
     } finally {
       setAdding(false);
     }
@@ -127,14 +129,14 @@ export function ChannelWritersTab({
   return (
     <div className="max-w-3xl space-y-5">
       <p className="text-sm text-muted-foreground">
-        Manage which users are allowed to write/edit files in group chats.
+        {t("detail.writers.description")}
       </p>
 
       {/* Groups accordion */}
       <div className="space-y-2">
         <div className="flex items-center justify-between">
           <h3 className="text-sm font-medium">
-            Groups
+            {t("detail.writers.groups")}
             {groups.length > 0 && (
               <span className="ml-1.5 text-muted-foreground font-normal">({groups.length})</span>
             )}
@@ -147,8 +149,8 @@ export function ChannelWritersTab({
         {groups.length === 0 && !loadingGroups ? (
           <EmptyState
             icon={Users}
-            title="No writer groups"
-            description="Use the form below to add writers to a group."
+            title={t("detail.writers.noWriterGroups")}
+            description={t("detail.writers.noWriterGroupsHint")}
           />
         ) : (
           <div className="rounded-md border divide-y">
@@ -174,7 +176,9 @@ export function ChannelWritersTab({
                       <span className="ml-2 text-xs text-muted-foreground">{g.group_id}</span>
                     </div>
                     <span className="shrink-0 rounded-full bg-muted px-2 py-0.5 text-xs font-medium tabular-nums">
-                      {g.writer_count} {g.writer_count === 1 ? "writer" : "writers"}
+                      {g.writer_count === 1
+                        ? t("detail.writers.writersCount", { count: g.writer_count })
+                        : t("detail.writers.writersCountPlural", { count: g.writer_count })}
                     </span>
                   </button>
 
@@ -182,17 +186,17 @@ export function ChannelWritersTab({
                   {isOpen && (
                     <div className="border-t bg-muted/10 px-4 py-3 space-y-3">
                       {isLoading ? (
-                        <p className="text-sm text-muted-foreground py-2">Loading writers...</p>
+                        <p className="text-sm text-muted-foreground py-2">{t("detail.writers.loadingWriters")}</p>
                       ) : groupWriters.length === 0 ? (
-                        <p className="text-sm text-muted-foreground py-2">No writers in this group.</p>
+                        <p className="text-sm text-muted-foreground py-2">{t("detail.writers.noWriters")}</p>
                       ) : (
                         <div className="rounded-md border bg-background">
                           <table className="w-full text-sm">
                             <thead>
                               <tr className="border-b bg-muted/50">
-                                <th className="px-3 py-2 text-left font-medium text-xs uppercase tracking-wide text-muted-foreground">User ID</th>
-                                <th className="px-3 py-2 text-left font-medium text-xs uppercase tracking-wide text-muted-foreground">Name</th>
-                                <th className="px-3 py-2 text-left font-medium text-xs uppercase tracking-wide text-muted-foreground">Username</th>
+                                <th className="px-3 py-2 text-left font-medium text-xs uppercase tracking-wide text-muted-foreground">{t("detail.writers.columns.userId")}</th>
+                                <th className="px-3 py-2 text-left font-medium text-xs uppercase tracking-wide text-muted-foreground">{t("detail.writers.columns.name")}</th>
+                                <th className="px-3 py-2 text-left font-medium text-xs uppercase tracking-wide text-muted-foreground">{t("detail.writers.columns.username")}</th>
                                 <th className="px-3 py-2 w-10" />
                               </tr>
                             </thead>
@@ -222,30 +226,30 @@ export function ChannelWritersTab({
                       {/* Inline add form for this group */}
                       <div className="flex items-end gap-2">
                         <div className="grid gap-1 flex-1">
-                          <Label className="text-xs text-muted-foreground">User ID</Label>
+                          <Label className="text-xs text-muted-foreground">{t("detail.writers.addForm.userId")}</Label>
                           <Input
                             value={addUserId}
                             onChange={(e) => setAddUserId(e.target.value)}
-                            placeholder="e.g. 12345678"
+                            placeholder={t("detail.writers.addForm.userIdPlaceholder")}
                             className="h-8 text-sm"
                             onKeyDown={(e) => e.key === "Enter" && (e.preventDefault(), handleAddWriter(g.group_id))}
                           />
                         </div>
                         <div className="grid gap-1 flex-1">
-                          <Label className="text-xs text-muted-foreground">Display Name</Label>
+                          <Label className="text-xs text-muted-foreground">{t("detail.writers.addForm.displayName")}</Label>
                           <Input
                             value={addDisplayName}
                             onChange={(e) => setAddDisplayName(e.target.value)}
-                            placeholder="Optional"
+                            placeholder={t("detail.writers.addForm.optional")}
                             className="h-8 text-sm"
                           />
                         </div>
                         <div className="grid gap-1 flex-1">
-                          <Label className="text-xs text-muted-foreground">Username</Label>
+                          <Label className="text-xs text-muted-foreground">{t("detail.writers.addForm.username")}</Label>
                           <Input
                             value={addUsername}
                             onChange={(e) => setAddUsername(e.target.value)}
-                            placeholder="Optional"
+                            placeholder={t("detail.writers.addForm.optional")}
                             className="h-8 text-sm"
                           />
                         </div>
@@ -256,7 +260,7 @@ export function ChannelWritersTab({
                           disabled={adding || !addUserId.trim()}
                         >
                           <Plus className="h-3.5 w-3.5" />
-                          Add
+                          {t("detail.writers.addForm.add")}
                         </Button>
                       </div>
                     </div>
@@ -270,48 +274,46 @@ export function ChannelWritersTab({
 
       {/* Add to new group */}
       <fieldset className="rounded-md border p-4 space-y-3">
-        <legend className="px-1 text-sm font-medium">Add Writer to New Group</legend>
-        <p className="text-xs text-muted-foreground">
-          Add a writer to a group that doesn&apos;t appear in the list above.
-        </p>
+        <legend className="px-1 text-sm font-medium">{t("detail.writers.addForm.title")}</legend>
+        <p className="text-xs text-muted-foreground">{t("detail.writers.addForm.hint")}</p>
         <div className="grid grid-cols-2 gap-3">
           <div className="grid gap-1.5">
-            <Label htmlFor="aw-group" className="text-xs">Group ID *</Label>
+            <Label htmlFor="aw-group" className="text-xs">{t("detail.writers.addForm.groupId")}</Label>
             <Input
               id="aw-group"
               value={addGroupId}
               onChange={(e) => setAddGroupId(e.target.value)}
-              placeholder="e.g. group:telegram:-100123456"
+              placeholder={t("detail.writers.addForm.groupIdPlaceholder")}
               className="text-sm"
             />
           </div>
           <div className="grid gap-1.5">
-            <Label htmlFor="aw-user" className="text-xs">User ID *</Label>
+            <Label htmlFor="aw-user" className="text-xs">{t("detail.writers.addForm.userId")}</Label>
             <Input
               id="aw-user"
               value={addUserId}
               onChange={(e) => setAddUserId(e.target.value)}
-              placeholder="e.g. 12345678"
+              placeholder={t("detail.writers.addForm.userIdPlaceholder")}
               className="text-sm"
             />
           </div>
           <div className="grid gap-1.5">
-            <Label htmlFor="aw-display" className="text-xs">Display Name</Label>
+            <Label htmlFor="aw-display" className="text-xs">{t("detail.writers.addForm.displayName")}</Label>
             <Input
               id="aw-display"
               value={addDisplayName}
               onChange={(e) => setAddDisplayName(e.target.value)}
-              placeholder="Optional"
+              placeholder={t("detail.writers.addForm.optional")}
               className="text-sm"
             />
           </div>
           <div className="grid gap-1.5">
-            <Label htmlFor="aw-username" className="text-xs">Username</Label>
+            <Label htmlFor="aw-username" className="text-xs">{t("detail.writers.addForm.username")}</Label>
             <Input
               id="aw-username"
               value={addUsername}
               onChange={(e) => setAddUsername(e.target.value)}
-              placeholder="Optional (without @)"
+              placeholder={t("detail.writers.addForm.usernameWithout")}
               className="text-sm"
             />
           </div>
@@ -325,7 +327,7 @@ export function ChannelWritersTab({
             className="gap-1"
           >
             <Plus className="h-3.5 w-3.5" />
-            {adding ? "Adding..." : "Add Writer"}
+            {adding ? t("detail.writers.addForm.adding") : t("detail.writers.addForm.addWriter")}
           </Button>
         </div>
       </fieldset>
diff --git a/ui/web/src/pages/channels/channel-fields.tsx b/ui/web/src/pages/channels/channel-fields.tsx
index 345d3987..d664ef82 100644
--- a/ui/web/src/pages/channels/channel-fields.tsx
+++ b/ui/web/src/pages/channels/channel-fields.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import { Switch } from "@/components/ui/switch";
@@ -49,8 +50,9 @@ function FieldRenderer({
   id: string;
   isEdit?: boolean;
 }) {
+  const { t } = useTranslation("channels");
   const labelSuffix = field.required && !isEdit ? " *" : "";
-  const editHint = isEdit && field.type === "password" ? " (leave blank to keep current)" : "";
+  const editHint = isEdit && field.type === "password" ? ` ${t("form.credentialsHint")}` : "";
 
   switch (field.type) {
     case "text":
@@ -133,7 +135,7 @@ function FieldRenderer({
               const lines = e.target.value.split("\n").map((l) => l.trim()).filter(Boolean);
               onChange(lines.length > 0 ? lines : undefined);
             }}
-            placeholder="One per line"
+            placeholder={t("groupOverrides.fields.allowedUsersPlaceholder")}
             rows={3}
             className="font-mono text-sm"
           />
diff --git a/ui/web/src/pages/channels/channel-instance-form-dialog.tsx b/ui/web/src/pages/channels/channel-instance-form-dialog.tsx
index 6e80609f..6d383962 100644
--- a/ui/web/src/pages/channels/channel-instance-form-dialog.tsx
+++ b/ui/web/src/pages/channels/channel-instance-form-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -45,6 +46,8 @@ export function ChannelInstanceFormDialog({
   onSubmit,
   onUpdate,
 }: ChannelInstanceFormDialogProps) {
+  const { t } = useTranslation("channels");
+
   const [name, setName] = useState("");
   const [displayName, setDisplayName] = useState("");
   const [channelType, setChannelType] = useState("telegram");
@@ -141,18 +144,18 @@ export function ChannelInstanceFormDialog({
   };
 
   const handleSubmit = async () => {
-    if (!name.trim()) { setError("Key is required"); return; }
+    if (!name.trim()) { setError(t("form.errors.keyRequired")); return; }
     if (!isValidSlug(name.trim())) {
-      setError("Key must be a valid slug (lowercase letters, numbers, hyphens only)");
+      setError(t("form.errors.keySlug"));
       return;
     }
-    if (!agentId) { setError("Agent is required"); return; }
+    if (!agentId) { setError(t("form.errors.agentRequired")); return; }
 
     if (!instance) {
       const schema = credentialsSchema[channelType] ?? [];
       const missing = schema.filter((f) => f.required && !credsValues[f.key]);
       if (missing.length > 0) {
-        setError(`Required: ${missing.map((f) => f.label).join(", ")}`);
+        setError(t("form.errors.requiredFields", { fields: missing.map((f) => f.label).join(", ") }));
         return;
       }
     }
@@ -193,7 +196,7 @@ export function ChannelInstanceFormDialog({
         onOpenChange(false);
       }
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Failed to save");
+      setError(err instanceof Error ? err.message : t("form.errors.failedSave"));
     } finally {
       setLoading(false);
     }
@@ -211,7 +214,7 @@ export function ChannelInstanceFormDialog({
       await onUpdate(createdInstanceId, { config: cleanConfig });
       onOpenChange(false);
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Failed to save configuration");
+      setError(err instanceof Error ? err.message : t("form.errors.failedSaveConfig"));
     } finally {
       setLoading(false);
     }
@@ -235,12 +238,12 @@ export function ChannelInstanceFormDialog({
   const EditConfig = wizardEditConfigs[channelType];
 
   const dialogTitle = instance
-    ? "Edit Channel Instance"
+    ? t("form.editTitle")
     : step === "form"
-      ? "Create Channel Instance"
+      ? t("form.createTitle")
       : step === "auth"
-        ? `Authenticate — ${channelLabel}`
-        : `Configure — ${channelLabel}`;
+        ? t("form.authenticate", { label: channelLabel })
+        : t("form.configure", { label: channelLabel });
 
   return (
     <Dialog open={open} onOpenChange={(v) => { if (!loading && canClose) onOpenChange(v); }}>
@@ -248,7 +251,9 @@ export function ChannelInstanceFormDialog({
         <DialogHeader>
           <DialogTitle>{dialogTitle}</DialogTitle>
           {hasWizard && (
-            <p className="text-xs text-muted-foreground">Step {currentStepNum} of {totalSteps}</p>
+            <p className="text-xs text-muted-foreground">
+              {t("form.step", { current: currentStepNum, total: totalSteps })}
+            </p>
           )}
         </DialogHeader>
 
@@ -257,18 +262,18 @@ export function ChannelInstanceFormDialog({
           <>
             <div className="grid gap-4 py-2 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
               <div className="grid gap-1.5">
-                <Label htmlFor="ci-name">Key *</Label>
-                <Input id="ci-name" value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder="my-telegram-bot" disabled={!!instance} />
-                <p className="text-xs text-muted-foreground">Unique slug used as channel identifier</p>
+                <Label htmlFor="ci-name">{t("form.key")}</Label>
+                <Input id="ci-name" value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder={t("form.keyPlaceholder")} disabled={!!instance} />
+                <p className="text-xs text-muted-foreground">{t("form.keyHint")}</p>
               </div>
 
               <div className="grid gap-1.5">
-                <Label htmlFor="ci-display">Display Name</Label>
-                <Input id="ci-display" value={displayName} onChange={(e) => setDisplayName(e.target.value)} placeholder="Sales Bot" />
+                <Label htmlFor="ci-display">{t("form.displayName")}</Label>
+                <Input id="ci-display" value={displayName} onChange={(e) => setDisplayName(e.target.value)} placeholder={t("form.displayNamePlaceholder")} />
               </div>
 
               <div className="grid gap-1.5">
-                <Label>Channel Type *</Label>
+                <Label>{t("form.channelType")}</Label>
                 <Select value={channelType} onValueChange={setChannelType} disabled={!!instance}>
                   <SelectTrigger><SelectValue /></SelectTrigger>
                   <SelectContent>
@@ -280,9 +285,9 @@ export function ChannelInstanceFormDialog({
               </div>
 
               <div className="grid gap-1.5">
-                <Label>Agent *</Label>
+                <Label>{t("form.agent")}</Label>
                 <Select value={agentId} onValueChange={setAgentId}>
-                  <SelectTrigger><SelectValue placeholder="Select agent" /></SelectTrigger>
+                  <SelectTrigger><SelectValue placeholder={t("form.selectAgent")} /></SelectTrigger>
                   <SelectContent>
                     {agents.map((a) => (
                       <SelectItem key={a.id} value={a.id}>{a.display_name || a.agent_key}</SelectItem>
@@ -294,11 +299,11 @@ export function ChannelInstanceFormDialog({
               {credsFields.length > 0 && (
                 <fieldset className="rounded-md border p-3 space-y-3">
                   <legend className="px-1 text-sm font-medium">
-                    Credentials
-                    {instance && <span className="text-xs font-normal text-muted-foreground ml-1">(leave blank to keep current)</span>}
+                    {t("form.credentials")}
+                    {instance && <span className="text-xs font-normal text-muted-foreground ml-1">{t("form.credentialsHint")}</span>}
                   </legend>
                   <ChannelFields fields={credsFields} values={credsValues} onChange={handleCredsChange} idPrefix="ci-cred" isEdit={!!instance} />
-                  <p className="text-xs text-muted-foreground">Encrypted server-side. Never returned in API responses.</p>
+                  <p className="text-xs text-muted-foreground">{t("form.credentialsEncrypted")}</p>
                 </fieldset>
               )}
 
@@ -307,9 +312,13 @@ export function ChannelInstanceFormDialog({
                 <div className="rounded-md border border-blue-200 bg-blue-50 dark:border-blue-900 dark:bg-blue-950 p-3">
                   <div className="flex items-center gap-2">
                     <span className={`h-2 w-2 rounded-full ${instance.has_credentials ? "bg-green-500" : "bg-amber-500"}`} />
-                    <span className="text-sm">{instance.has_credentials ? "Authenticated" : "Not authenticated"}</span>
+                    <span className="text-sm">
+                      {instance.has_credentials
+                        ? t("form.authStatus.authenticated")
+                        : t("form.authStatus.notAuthenticated")}
+                    </span>
                     {!instance.has_credentials && (
-                      <span className="text-xs text-muted-foreground ml-1">— Use the QR login button from the channels table</span>
+                      <span className="text-xs text-muted-foreground ml-1">{t("form.authStatus.useQrHint")}</span>
                     )}
                   </div>
                 </div>
@@ -324,7 +333,7 @@ export function ChannelInstanceFormDialog({
 
               {formCfgFields.length > 0 && (
                 <fieldset className="rounded-md border p-3 space-y-3">
-                  <legend className="px-1 text-sm font-medium">Configuration</legend>
+                  <legend className="px-1 text-sm font-medium">{t("form.configuration")}</legend>
                   <ChannelFields fields={formCfgFields} values={configValues} onChange={handleConfigChange} idPrefix="ci-cfg" />
                   {instance && EditConfig && <EditConfig instance={instance} configValues={configValues} onConfigChange={handleConfigChange} />}
                 </fieldset>
@@ -345,15 +354,15 @@ export function ChannelInstanceFormDialog({
 
               <div className="flex items-center gap-2">
                 <Switch id="ci-enabled" checked={enabled} onCheckedChange={setEnabled} />
-                <Label htmlFor="ci-enabled">Enabled</Label>
+                <Label htmlFor="ci-enabled">{t("form.enabled")}</Label>
               </div>
               {error && <p className="text-sm text-destructive">{error}</p>}
             </div>
 
             <DialogFooter>
-              <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>Cancel</Button>
+              <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>{t("form.cancel")}</Button>
               <Button onClick={handleSubmit} disabled={loading}>
-                {loading ? "Saving..." : instance ? "Update" : wizard?.createLabel ?? "Create"}
+                {loading ? t("form.saving") : instance ? t("form.update") : (wizard?.createLabel ?? t("form.create"))}
               </Button>
             </DialogFooter>
           </>
@@ -381,8 +390,8 @@ export function ChannelInstanceFormDialog({
               {error && <p className="text-sm text-destructive mt-2">{error}</p>}
             </div>
             <DialogFooter>
-              <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>Skip</Button>
-              <Button onClick={handleConfigDone} disabled={loading}>{loading ? "Saving..." : "Done"}</Button>
+              <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>{t("form.skip")}</Button>
+              <Button onClick={handleConfigDone} disabled={loading}>{loading ? t("form.saving") : t("form.done")}</Button>
             </DialogFooter>
           </>
         )}
diff --git a/ui/web/src/pages/channels/channels-page.tsx b/ui/web/src/pages/channels/channels-page.tsx
index 149f361d..20b02ded 100644
--- a/ui/web/src/pages/channels/channels-page.tsx
+++ b/ui/web/src/pages/channels/channels-page.tsx
@@ -1,6 +1,7 @@
 import { useState, useRef } from "react";
 import { useParams, useNavigate } from "react-router";
 import { Radio, Plus, RefreshCw, Pencil, Trash2, QrCode } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { PageHeader } from "@/components/shared/page-header";
@@ -21,6 +22,7 @@ import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 import { useDebouncedCallback } from "@/hooks/use-debounced-callback";
 
 export function ChannelsPage() {
+  const { t } = useTranslation("channels");
   const { id: detailId } = useParams<{ id: string }>();
   const navigate = useNavigate();
 
@@ -109,15 +111,15 @@ export function ChannelsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Channels"
-        description="Manage channel instances"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex gap-2">
             <Button size="sm" onClick={() => setFormOpen(true)} className="gap-1">
-              <Plus className="h-3.5 w-3.5" /> Add Channel
+              <Plus className="h-3.5 w-3.5" /> {t("addChannel")}
             </Button>
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("refresh")}
             </Button>
           </div>
         }
@@ -127,7 +129,7 @@ export function ChannelsPage() {
         <SearchInput
           value={search}
           onChange={handleSearchChange}
-          placeholder="Search channels..."
+          placeholder={t("searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -138,20 +140,20 @@ export function ChannelsPage() {
         ) : instances.length === 0 ? (
           <EmptyState
             icon={Radio}
-            title={debouncedSearch ? "No matching channels" : "No channels"}
-            description={debouncedSearch ? "Try a different search term." : "Add your first channel instance to get started."}
+            title={debouncedSearch ? t("noMatchTitle") : t("emptyTitle")}
+            description={debouncedSearch ? t("noMatchDescription") : t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Name</th>
-                  <th className="px-4 py-3 text-left font-medium">Type</th>
-                  <th className="px-4 py-3 text-left font-medium">Agent</th>
-                  <th className="px-4 py-3 text-left font-medium">Status</th>
-                  <th className="px-4 py-3 text-left font-medium">Enabled</th>
-                  <th className="px-4 py-3 text-right font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.name")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.type")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.agent")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.status")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.enabled")}</th>
+                  <th className="px-4 py-3 text-right font-medium">{t("columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -189,7 +191,7 @@ export function ChannelsPage() {
                               className={`h-2 w-2 rounded-full ${status.running ? "bg-green-500" : "bg-muted-foreground"}`}
                             />
                             <span className="text-muted-foreground">
-                              {status.running ? "Running" : "Stopped"}
+                              {status.running ? t("status.running") : t("status.stopped")}
                             </span>
                           </div>
                         ) : (
@@ -198,7 +200,7 @@ export function ChannelsPage() {
                       </td>
                       <td className="px-4 py-3">
                         <Badge variant={inst.enabled ? "default" : "secondary"}>
-                          {inst.enabled ? "Enabled" : "Disabled"}
+                          {inst.enabled ? t("enabled") : t("disabled")}
                         </Badge>
                       </td>
                       <td className="px-4 py-3 text-right">
@@ -207,7 +209,7 @@ export function ChannelsPage() {
                             <Button
                               variant="ghost"
                               size="sm"
-                              title={status?.running ? "Re-authenticate" : "Authenticate to start channel"}
+                              title={status?.running ? t("actions.reauthenticate") : t("actions.authenticate")}
                               onClick={(e) => { e.stopPropagation(); setQrTarget(inst); }}
                             >
                               <QrCode className="h-3.5 w-3.5" />
@@ -267,10 +269,10 @@ export function ChannelsPage() {
       <ConfirmDeleteDialog
         open={!!deleteTarget}
         onOpenChange={(v) => !v && setDeleteTarget(null)}
-        title="Delete Channel Instance"
-        description={`Are you sure you want to delete "${deleteTarget?.display_name || deleteTarget?.name}"? This action cannot be undone.`}
+        title={t("delete.title")}
+        description={t("delete.description", { name: deleteTarget?.display_name || deleteTarget?.name })}
         confirmValue={deleteTarget?.display_name || deleteTarget?.name || ""}
-        confirmLabel="Delete"
+        confirmLabel={t("delete.confirmLabel")}
         onConfirm={handleDelete}
         loading={deleteLoading}
       />
diff --git a/ui/web/src/pages/channels/channels-status-view.tsx b/ui/web/src/pages/channels/channels-status-view.tsx
index baffa3aa..735fb7d1 100644
--- a/ui/web/src/pages/channels/channels-status-view.tsx
+++ b/ui/web/src/pages/channels/channels-status-view.tsx
@@ -1,4 +1,5 @@
 import { Radio, RefreshCw } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { PageHeader } from "@/components/shared/page-header";
@@ -27,17 +28,18 @@ interface ChannelsStatusViewProps {
 }
 
 export function ChannelsStatusView({ channels, loading, spinning, refresh }: ChannelsStatusViewProps) {
+  const { t } = useTranslation("channels");
   const entries = Object.entries(channels);
   const showSkeleton = useDeferredLoading(loading && entries.length === 0);
 
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Channels"
-        description="Communication channel status"
+        title={t("title")}
+        description={t("statusDescription")}
         actions={
           <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("refresh")}
           </Button>
         }
       />
@@ -52,8 +54,8 @@ export function ChannelsStatusView({ channels, loading, spinning, refresh }: Cha
         ) : entries.length === 0 ? (
           <EmptyState
             icon={Radio}
-            title="No channels"
-            description="No communication channels are configured."
+            title={t("emptyTitle")}
+            description={t("emptyStatusDescription")}
           />
         ) : (
           <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
@@ -64,9 +66,9 @@ export function ChannelsStatusView({ channels, loading, spinning, refresh }: Cha
                     {channelTypeLabels[name] || name}
                   </h4>
                   {status.enabled ? (
-                    <Badge variant="success">enabled</Badge>
+                    <Badge variant="success">{t("enabled")}</Badge>
                   ) : (
-                    <Badge variant="secondary">disabled</Badge>
+                    <Badge variant="secondary">{t("disabled")}</Badge>
                   )}
                 </div>
                 <div className="mt-3 flex items-center gap-2 text-sm">
@@ -74,7 +76,7 @@ export function ChannelsStatusView({ channels, loading, spinning, refresh }: Cha
                     className={`h-2 w-2 rounded-full ${status.running ? "bg-green-500" : "bg-muted-foreground"}`}
                   />
                   <span className="text-muted-foreground">
-                    {status.running ? "Running" : "Stopped"}
+                    {status.running ? t("status.running") : t("status.stopped")}
                   </span>
                 </div>
               </div>
diff --git a/ui/web/src/pages/channels/hooks/use-channel-instances.ts b/ui/web/src/pages/channels/hooks/use-channel-instances.ts
index b43af48f..e1da29ab 100644
--- a/ui/web/src/pages/channels/hooks/use-channel-instances.ts
+++ b/ui/web/src/pages/channels/hooks/use-channel-instances.ts
@@ -1,5 +1,6 @@
 import { useCallback } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
+import i18next from "i18next";
 import { useHttp } from "@/hooks/use-ws";
 import { queryKeys } from "@/lib/query-keys";
 import { toast } from "@/stores/use-toast-store";
@@ -46,10 +47,13 @@ export function useChannelInstances(filters: ChannelInstanceFilters = {}) {
       try {
         const res = await http.post<{ id: string }>("/v1/channels/instances", data);
         await invalidate();
-        toast.success("Channel created", `${data.name} has been added`);
+        toast.success(
+          i18next.t("channels:toast.created"),
+          i18next.t("channels:toast.createdDesc", { name: data.name }),
+        );
         return res;
       } catch (err) {
-        toast.error("Failed to create channel", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("channels:toast.failedCreate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -61,9 +65,9 @@ export function useChannelInstances(filters: ChannelInstanceFilters = {}) {
       try {
         await http.put(`/v1/channels/instances/${id}`, data);
         await invalidate();
-        toast.success("Channel updated");
+        toast.success(i18next.t("channels:toast.updated"));
       } catch (err) {
-        toast.error("Failed to update channel", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("channels:toast.failedUpdate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -75,9 +79,9 @@ export function useChannelInstances(filters: ChannelInstanceFilters = {}) {
       try {
         await http.delete(`/v1/channels/instances/${id}`);
         await invalidate();
-        toast.success("Channel deleted");
+        toast.success(i18next.t("channels:toast.deleted"));
       } catch (err) {
-        toast.error("Failed to delete channel", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("channels:toast.failedDelete"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
diff --git a/ui/web/src/pages/channels/telegram-group-fields.tsx b/ui/web/src/pages/channels/telegram-group-fields.tsx
index 237b59ab..32ab8300 100644
--- a/ui/web/src/pages/channels/telegram-group-fields.tsx
+++ b/ui/web/src/pages/channels/telegram-group-fields.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Label } from "@/components/ui/label";
 import { Textarea } from "@/components/ui/textarea";
 import {
@@ -22,17 +23,6 @@ export interface TelegramGroupConfigValues {
 
 const INHERIT = "__inherit__";
 
-const triStateOptions = [
-  { value: INHERIT, label: "Inherit (channel default)" },
-  { value: "true", label: "Yes" },
-  { value: "false", label: "No" },
-];
-
-const groupPolicyWithInherit = [
-  { value: INHERIT, label: "Inherit (channel default)" },
-  ...groupPolicyOptions,
-];
-
 function triStateValue(val: boolean | undefined): string {
   if (val === undefined || val === null) return INHERIT;
   return val ? "true" : "false";
@@ -50,6 +40,23 @@ interface Props {
 }
 
 export function TelegramGroupFields({ config, onChange, idPrefix }: Props) {
+  const { t } = useTranslation("channels");
+
+  const inheritLabel = t("groupOverrides.fields.inherit");
+  const yesLabel = t("groupOverrides.fields.yes");
+  const noLabel = t("groupOverrides.fields.no");
+
+  const triStateOptions = [
+    { value: INHERIT, label: inheritLabel },
+    { value: "true", label: yesLabel },
+    { value: "false", label: noLabel },
+  ];
+
+  const groupPolicyWithInherit = [
+    { value: INHERIT, label: inheritLabel },
+    ...groupPolicyOptions,
+  ];
+
   const update = (patch: Partial<TelegramGroupConfigValues>) => {
     onChange({ ...config, ...patch });
   };
@@ -57,7 +64,7 @@ export function TelegramGroupFields({ config, onChange, idPrefix }: Props) {
   return (
     <div className="grid gap-3">
       <div className="grid gap-1.5">
-        <Label>Group Policy</Label>
+        <Label>{t("groupOverrides.fields.groupPolicy")}</Label>
         <Select
           value={config.group_policy || INHERIT}
           onValueChange={(v) => update({ group_policy: v === INHERIT ? undefined : v })}
@@ -76,7 +83,7 @@ export function TelegramGroupFields({ config, onChange, idPrefix }: Props) {
       </div>
 
       <div className="grid gap-1.5">
-        <Label>Require @mention</Label>
+        <Label>{t("groupOverrides.fields.requireMention")}</Label>
         <Select
           value={triStateValue(config.require_mention)}
           onValueChange={(v) => update({ require_mention: parseTriState(v) })}
@@ -95,7 +102,7 @@ export function TelegramGroupFields({ config, onChange, idPrefix }: Props) {
       </div>
 
       <div className="grid gap-1.5">
-        <Label>Enabled</Label>
+        <Label>{t("groupOverrides.fields.enabled")}</Label>
         <Select
           value={triStateValue(config.enabled)}
           onValueChange={(v) => update({ enabled: parseTriState(v) })}
@@ -114,7 +121,7 @@ export function TelegramGroupFields({ config, onChange, idPrefix }: Props) {
       </div>
 
       <div className="grid gap-1.5">
-        <Label htmlFor={`${idPrefix}-allow`}>Allowed Users</Label>
+        <Label htmlFor={`${idPrefix}-allow`}>{t("groupOverrides.fields.allowedUsers")}</Label>
         <Textarea
           id={`${idPrefix}-allow`}
           value={config.allow_from?.join("\n") ?? ""}
@@ -122,14 +129,14 @@ export function TelegramGroupFields({ config, onChange, idPrefix }: Props) {
             const lines = e.target.value.split("\n").map((l) => l.trim()).filter(Boolean);
             update({ allow_from: lines.length > 0 ? lines : undefined });
           }}
-          placeholder="One user ID per line"
+          placeholder={t("groupOverrides.fields.allowedUsersPlaceholder")}
           rows={2}
           className="font-mono text-sm"
         />
       </div>
 
       <div className="grid gap-1.5">
-        <Label htmlFor={`${idPrefix}-skills`}>Skills Filter</Label>
+        <Label htmlFor={`${idPrefix}-skills`}>{t("groupOverrides.fields.skillsFilter")}</Label>
         <Textarea
           id={`${idPrefix}-skills`}
           value={config.skills?.join("\n") ?? ""}
@@ -137,31 +144,31 @@ export function TelegramGroupFields({ config, onChange, idPrefix }: Props) {
             const lines = e.target.value.split("\n").map((l) => l.trim()).filter(Boolean);
             update({ skills: lines.length > 0 ? lines : undefined });
           }}
-          placeholder="One skill name per line (empty = inherit)"
+          placeholder={t("groupOverrides.fields.skillsPlaceholder")}
           rows={2}
           className="font-mono text-sm"
         />
       </div>
 
       <div className="grid gap-1.5">
-        <Label>Tool Allow</Label>
+        <Label>{t("groupOverrides.fields.toolAllow")}</Label>
         <ToolNameSelect
           value={config.tools ?? []}
           onChange={(v) => update({ tools: v.length > 0 ? v : undefined })}
-          placeholder="Select allowed tools (empty = inherit all)..."
+          placeholder={t("groupOverrides.fields.toolAllowPlaceholder")}
         />
         <p className="text-xs text-muted-foreground">
-          Restrict which tools are available in this group. Supports group names like &quot;group:web&quot;, &quot;group:fs&quot;. Empty = inherit all tools.
+          {t("groupOverrides.fields.toolAllowHint")}
         </p>
       </div>
 
       <div className="grid gap-1.5">
-        <Label htmlFor={`${idPrefix}-prompt`}>System Prompt</Label>
+        <Label htmlFor={`${idPrefix}-prompt`}>{t("groupOverrides.fields.systemPrompt")}</Label>
         <Textarea
           id={`${idPrefix}-prompt`}
           value={config.system_prompt ?? ""}
           onChange={(e) => update({ system_prompt: e.target.value || undefined })}
-          placeholder="Additional system prompt for this group/topic"
+          placeholder={t("groupOverrides.fields.systemPromptPlaceholder")}
           rows={3}
         />
       </div>
diff --git a/ui/web/src/pages/channels/telegram-group-overrides.tsx b/ui/web/src/pages/channels/telegram-group-overrides.tsx
index 36f714a7..ddd58103 100644
--- a/ui/web/src/pages/channels/telegram-group-overrides.tsx
+++ b/ui/web/src/pages/channels/telegram-group-overrides.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Plus, Trash2, ChevronDown, ChevronRight } from "lucide-react";
@@ -15,6 +16,7 @@ interface Props {
 }
 
 export function TelegramGroupOverrides({ groups, onChange }: Props) {
+  const { t } = useTranslation("channels");
   const [expanded, setExpanded] = useState<Record<string, boolean>>({});
   const [newGroupId, setNewGroupId] = useState("");
 
@@ -53,10 +55,8 @@ export function TelegramGroupOverrides({ groups, onChange }: Props) {
 
   return (
     <fieldset className="rounded-md border p-3 space-y-3">
-      <legend className="px-1 text-sm font-medium">Group & Topic Overrides</legend>
-      <p className="text-xs text-muted-foreground">
-        Override channel defaults per group chat or forum topic. Use &quot;*&quot; as group ID for wildcard defaults.
-      </p>
+      <legend className="px-1 text-sm font-medium">{t("groupOverrides.title")}</legend>
+      <p className="text-xs text-muted-foreground">{t("groupOverrides.hint")}</p>
 
       {groupIds.map((id) => {
         const group = groups[id] ?? {};
@@ -69,7 +69,9 @@ export function TelegramGroupOverrides({ groups, onChange }: Props) {
                 onClick={() => toggle(id)}
               >
                 {expanded[id] ? <ChevronDown className="h-4 w-4" /> : <ChevronRight className="h-4 w-4" />}
-                Group: {id === "*" ? "* (wildcard)" : id}
+                {id === "*"
+                  ? t("groupOverrides.groupWildcard")
+                  : t("groupOverrides.groupLabel", { id })}
               </button>
               <Button
                 type="button"
@@ -104,13 +106,13 @@ export function TelegramGroupOverrides({ groups, onChange }: Props) {
         <Input
           value={newGroupId}
           onChange={(e) => setNewGroupId(e.target.value)}
-          placeholder="Chat ID (e.g. -100123456) or *"
+          placeholder={t("groupOverrides.addGroupPlaceholder")}
           className="h-8 flex-1 text-sm"
           onKeyDown={(e) => e.key === "Enter" && (e.preventDefault(), addGroup())}
         />
         <Button type="button" variant="outline" size="sm" className="h-8" onClick={addGroup} disabled={!newGroupId.trim()}>
           <Plus className="h-3.5 w-3.5 mr-1" />
-          Add Group
+          {t("groupOverrides.addGroup")}
         </Button>
       </div>
     </fieldset>
diff --git a/ui/web/src/pages/channels/telegram-topic-overrides.tsx b/ui/web/src/pages/channels/telegram-topic-overrides.tsx
index d9df174d..ae7d27aa 100644
--- a/ui/web/src/pages/channels/telegram-topic-overrides.tsx
+++ b/ui/web/src/pages/channels/telegram-topic-overrides.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -13,6 +14,7 @@ interface Props {
 }
 
 export function TelegramTopicOverrides({ topics, onChange }: Props) {
+  const { t } = useTranslation("channels");
   const [expanded, setExpanded] = useState<Record<string, boolean>>({});
   const [newTopicId, setNewTopicId] = useState("");
 
@@ -42,7 +44,7 @@ export function TelegramTopicOverrides({ topics, onChange }: Props) {
 
   return (
     <div className="space-y-2">
-      <Label className="text-xs font-medium text-muted-foreground">Topic Overrides</Label>
+      <Label className="text-xs font-medium text-muted-foreground">{t("groupOverrides.topicOverrides")}</Label>
 
       {topicIds.map((id) => (
         <div key={id} className="rounded-md border border-dashed p-2 space-y-2">
@@ -53,7 +55,7 @@ export function TelegramTopicOverrides({ topics, onChange }: Props) {
               onClick={() => toggle(id)}
             >
               {expanded[id] ? <ChevronDown className="h-3.5 w-3.5" /> : <ChevronRight className="h-3.5 w-3.5" />}
-              Topic: {id}
+              {t("groupOverrides.topicLabel", { id })}
             </button>
             <Button
               type="button"
@@ -82,13 +84,13 @@ export function TelegramTopicOverrides({ topics, onChange }: Props) {
         <Input
           value={newTopicId}
           onChange={(e) => setNewTopicId(e.target.value.replace(/\D/g, ""))}
-          placeholder="Topic thread ID"
+          placeholder={t("groupOverrides.addTopicPlaceholder")}
           className="h-8 w-40 text-sm"
           onKeyDown={(e) => e.key === "Enter" && (e.preventDefault(), addTopic())}
         />
         <Button type="button" variant="outline" size="sm" className="h-8" onClick={addTopic} disabled={!newTopicId.trim()}>
           <Plus className="h-3.5 w-3.5 mr-1" />
-          Add Topic
+          {t("groupOverrides.addTopic")}
         </Button>
       </div>
     </div>
diff --git a/ui/web/src/pages/channels/zalo/zalo-contacts-picker.tsx b/ui/web/src/pages/channels/zalo/zalo-contacts-picker.tsx
index 151e954e..191c3678 100644
--- a/ui/web/src/pages/channels/zalo/zalo-contacts-picker.tsx
+++ b/ui/web/src/pages/channels/zalo/zalo-contacts-picker.tsx
@@ -1,4 +1,5 @@
 import { useEffect, useRef, useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -32,6 +33,7 @@ interface ZaloContactsPickerProps {
 }
 
 export function ZaloContactsPicker({ instanceId, hasCredentials, value, onChange }: ZaloContactsPickerProps) {
+  const { t } = useTranslation("channels");
   const [contacts, setContacts] = useState<ContactsResult | null>(null);
   const [search, setSearch] = useState("");
   const [manualId, setManualId] = useState("");
@@ -82,8 +84,8 @@ export function ZaloContactsPicker({ instanceId, hasCredentials, value, onChange
   if (!hasCredentials) {
     return (
       <div className="grid gap-1.5">
-        <Label>Allowed Users</Label>
-        <p className="text-sm text-muted-foreground">Complete QR login to load contacts</p>
+        <Label>{t("zalo.allowedUsers")}</Label>
+        <p className="text-sm text-muted-foreground">{t("zalo.completeQrLogin")}</p>
       </div>
     );
   }
@@ -99,10 +101,10 @@ export function ZaloContactsPicker({ instanceId, hasCredentials, value, onChange
   return (
     <div className="space-y-3">
       <div className="flex items-center gap-2">
-        <Label>Allowed Users</Label>
+        <Label>{t("zalo.allowedUsers")}</Label>
         {!contacts && (
           <Button type="button" variant="outline" size="sm" onClick={handleLoad} disabled={loading}>
-            {loading ? "Loading..." : "Load Contacts"}
+            {loading ? t("zalo.loading") : t("zalo.loadContacts")}
           </Button>
         )}
       </div>
@@ -127,7 +129,7 @@ export function ZaloContactsPicker({ instanceId, hasCredentials, value, onChange
       {contacts && (
         <>
           <Input
-            placeholder="Search contacts..."
+            placeholder={t("zalo.searchContacts")}
             value={search}
             onChange={(e) => setSearch(e.target.value)}
             className="h-8"
@@ -135,7 +137,7 @@ export function ZaloContactsPicker({ instanceId, hasCredentials, value, onChange
           <div className="max-h-48 overflow-y-auto rounded border p-2 space-y-1">
             {filteredFriends.length > 0 && (
               <>
-                <p className="text-xs font-medium text-muted-foreground">Friends</p>
+                <p className="text-xs font-medium text-muted-foreground">{t("zalo.friends")}</p>
                 {filteredFriends.map((f) => (
                   <label key={f.userId} className="flex items-center gap-2 py-0.5 text-sm cursor-pointer hover:bg-muted/50 rounded px-1">
                     <input type="checkbox" checked={value.includes(f.userId)} onChange={() => toggle(f.userId)} />
@@ -147,19 +149,19 @@ export function ZaloContactsPicker({ instanceId, hasCredentials, value, onChange
             )}
             {filteredGroups.length > 0 && (
               <>
-                <p className="text-xs font-medium text-muted-foreground mt-2">Groups</p>
+                <p className="text-xs font-medium text-muted-foreground mt-2">{t("zalo.groups")}</p>
                 {filteredGroups.map((g) => (
                   <label key={g.groupId} className="flex items-center gap-2 py-0.5 text-sm cursor-pointer hover:bg-muted/50 rounded px-1">
                     <input type="checkbox" checked={value.includes(g.groupId)} onChange={() => toggle(g.groupId)} />
                     <span>{g.name}</span>
-                    <span className="text-xs text-muted-foreground ml-auto">{g.totalMember} members</span>
+                    <span className="text-xs text-muted-foreground ml-auto">{t("zalo.membersCount", { count: g.totalMember })}</span>
                   </label>
                 ))}
               </>
             )}
             {filteredFriends.length === 0 && filteredGroups.length === 0 && (
               <p className="text-sm text-muted-foreground py-2 text-center">
-                {search ? `No contacts match "${search}"` : "No contacts found"}
+                {search ? t("zalo.noContactsMatch", { search }) : t("zalo.noContacts")}
               </p>
             )}
           </div>
@@ -169,17 +171,17 @@ export function ZaloContactsPicker({ instanceId, hasCredentials, value, onChange
       {/* Manual ID entry */}
       <div className="flex gap-2">
         <Input
-          placeholder="Add ID manually"
+          placeholder={t("zalo.addManualPlaceholder")}
           value={manualId}
           onChange={(e) => setManualId(e.target.value)}
           onKeyDown={(e) => { if (e.key === "Enter") { e.preventDefault(); addManual(); } }}
           className="h-8"
         />
         <Button type="button" variant="outline" size="sm" onClick={addManual} disabled={!manualId.trim()}>
-          Add
+          {t("zalo.add")}
         </Button>
       </div>
-      <p className="text-xs text-muted-foreground">Zalo user IDs or group IDs</p>
+      <p className="text-xs text-muted-foreground">{t("zalo.zaloIdsHint")}</p>
     </div>
   );
 }
diff --git a/ui/web/src/pages/channels/zalo/zalo-personal-qr-dialog.tsx b/ui/web/src/pages/channels/zalo/zalo-personal-qr-dialog.tsx
index 53c48b53..d0cc1a9f 100644
--- a/ui/web/src/pages/channels/zalo/zalo-personal-qr-dialog.tsx
+++ b/ui/web/src/pages/channels/zalo/zalo-personal-qr-dialog.tsx
@@ -1,4 +1,5 @@
 import { useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -23,6 +24,7 @@ export function ZaloPersonalQRDialog({
   instanceName,
   onSuccess,
 }: ZaloPersonalQRDialogProps) {
+  const { t } = useTranslation("channels");
   const { qrPng, status, errorMsg, loading, start, reset } = useZaloQrLogin(instanceId);
 
   // Auto-start when dialog opens
@@ -47,12 +49,12 @@ export function ZaloPersonalQRDialog({
     <Dialog open={open} onOpenChange={(v) => { if (!loading) onOpenChange(v); }}>
       <DialogContent className="sm:max-w-sm">
         <DialogHeader>
-          <DialogTitle>Login with QR — {instanceName}</DialogTitle>
+          <DialogTitle>{t("zalo.loginQr", { name: instanceName })}</DialogTitle>
         </DialogHeader>
 
         <div className="flex flex-col items-center gap-4 py-4">
           {status === "done" && (
-            <p className="text-sm text-green-600 font-medium">Login successful! Channel starting...</p>
+            <p className="text-sm text-green-600 font-medium">{t("zalo.loginSuccessful")}</p>
           )}
           {status === "error" && (
             <p className="text-sm text-destructive">{errorMsg}</p>
@@ -65,17 +67,17 @@ export function ZaloPersonalQRDialog({
             />
           )}
           {status === "waiting" && !qrPng && (
-            <p className="text-sm text-muted-foreground">Generating QR code...</p>
+            <p className="text-sm text-muted-foreground">{t("zalo.generatingQr")}</p>
           )}
           {status === "waiting" && qrPng && (
-            <p className="text-xs text-muted-foreground">Scan with your Zalo app (expires in ~100s)</p>
+            <p className="text-xs text-muted-foreground">{t("zalo.scanHint")}</p>
           )}
         </div>
 
         <div className="flex justify-end gap-2">
-          <Button variant="outline" onClick={() => onOpenChange(false)}>Close</Button>
+          <Button variant="outline" onClick={() => onOpenChange(false)}>{t("zalo.close")}</Button>
           {status === "error" && (
-            <Button onClick={start} disabled={loading}>Retry</Button>
+            <Button onClick={start} disabled={loading}>{t("zalo.retry")}</Button>
           )}
         </div>
       </DialogContent>
diff --git a/ui/web/src/pages/channels/zalo/zalo-wizard-steps.tsx b/ui/web/src/pages/channels/zalo/zalo-wizard-steps.tsx
index 90114b8f..16a73601 100644
--- a/ui/web/src/pages/channels/zalo/zalo-wizard-steps.tsx
+++ b/ui/web/src/pages/channels/zalo/zalo-wizard-steps.tsx
@@ -2,6 +2,7 @@
 // Registered in channel-wizard-registry.tsx.
 
 import { useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { DialogFooter } from "@/components/ui/dialog";
 import { useZaloQrLogin } from "./use-zalo-qr-login";
@@ -10,6 +11,7 @@ import type { WizardAuthStepProps, WizardConfigStepProps, WizardEditConfigProps
 
 /** QR code authentication step for Zalo Personal */
 export function ZaloAuthStep({ instanceId, onComplete, onSkip }: WizardAuthStepProps) {
+  const { t } = useTranslation("channels");
   const { qrPng, status, errorMsg, loading, start, retry, reset } = useZaloQrLogin(instanceId);
 
   // Auto-start QR on mount
@@ -26,15 +28,15 @@ export function ZaloAuthStep({ instanceId, onComplete, onSkip }: WizardAuthStepP
   return (
     <>
       <div className="flex flex-col items-center gap-4 py-4 min-h-0">
-        {status === "done" && <p className="text-sm text-green-600 font-medium">Login successful! Loading contacts...</p>}
+        {status === "done" && <p className="text-sm text-green-600 font-medium">{t("zalo.loginSuccessLoading")}</p>}
         {status === "error" && <p className="text-sm text-destructive">{errorMsg}</p>}
         {qrPng && status === "waiting" && <img src={`data:image/png;base64,${qrPng}`} alt="Zalo QR Code" className="w-48 h-48 border rounded" />}
-        {status === "waiting" && !qrPng && <p className="text-sm text-muted-foreground">Generating QR code...</p>}
-        {status === "waiting" && qrPng && <p className="text-xs text-muted-foreground">Scan with your Zalo app (expires in ~100s)</p>}
+        {status === "waiting" && !qrPng && <p className="text-sm text-muted-foreground">{t("zalo.generatingQr")}</p>}
+        {status === "waiting" && qrPng && <p className="text-xs text-muted-foreground">{t("zalo.scanHint")}</p>}
       </div>
       <DialogFooter>
-        <Button variant="outline" onClick={onSkip} disabled={loading}>Skip</Button>
-        {status === "error" && <Button onClick={retry} disabled={loading}>Retry</Button>}
+        <Button variant="outline" onClick={onSkip} disabled={loading}>{t("zalo.skip")}</Button>
+        {status === "error" && <Button onClick={retry} disabled={loading}>{t("zalo.retry")}</Button>}
       </DialogFooter>
     </>
   );
diff --git a/ui/web/src/pages/chat/chat-page.tsx b/ui/web/src/pages/chat/chat-page.tsx
index 89636655..a031650d 100644
--- a/ui/web/src/pages/chat/chat-page.tsx
+++ b/ui/web/src/pages/chat/chat-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useCallback, useEffect, useRef } from "react";
+import { useTranslation } from "react-i18next";
 import { useParams, useNavigate } from "react-router";
 import { Eye, PanelLeftOpen } from "lucide-react";
 import { useAuthStore } from "@/stores/use-auth-store";
@@ -13,6 +14,7 @@ import { useChatSend } from "./hooks/use-chat-send";
 import { isOwnSession, parseSessionKey } from "@/lib/session-key";
 
 export function ChatPage() {
+  const { t } = useTranslation("chat");
   const { sessionKey: urlSessionKey } = useParams<{ sessionKey: string }>();
   const navigate = useNavigate();
   const connected = useAuthStore((s) => s.connected);
@@ -189,7 +191,7 @@ export function ChatPage() {
             <button
               onClick={() => setChatSidebarOpen(true)}
               className="rounded-md p-1.5 text-muted-foreground hover:bg-accent hover:text-accent-foreground"
-              title="Open sessions"
+              title={t("openSessions")}
             >
               <PanelLeftOpen className="h-4 w-4" />
             </button>
@@ -222,7 +224,7 @@ export function ChatPage() {
         ) : (
           <div className="flex items-center gap-2 border-t bg-muted/50 px-4 py-3 text-sm text-muted-foreground">
             <Eye className="h-4 w-4" />
-            Read-only — this session belongs to another user
+            {t("readOnly")}
           </div>
         )}
       </div>
diff --git a/ui/web/src/pages/chat/chat-sidebar.tsx b/ui/web/src/pages/chat/chat-sidebar.tsx
index 475fbc46..3b9f0e36 100644
--- a/ui/web/src/pages/chat/chat-sidebar.tsx
+++ b/ui/web/src/pages/chat/chat-sidebar.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Plus } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { AgentSelector } from "@/components/chat/agent-selector";
@@ -23,6 +24,7 @@ export function ChatSidebar({
   onSessionSelect,
   onNewChat,
 }: ChatSidebarProps) {
+  const { t } = useTranslation("chat");
   return (
     <div className="flex h-full w-72 max-w-[85vw] flex-col border-r bg-background">
       {/* Agent selector */}
@@ -38,7 +40,7 @@ export function ChatSidebar({
           onClick={onNewChat}
         >
           <Plus className="h-4 w-4" />
-          New Chat
+          {t("newChat")}
         </Button>
       </div>
 
diff --git a/ui/web/src/pages/chat/chat-thread.tsx b/ui/web/src/pages/chat/chat-thread.tsx
index 74f01ac4..e2aebb1e 100644
--- a/ui/web/src/pages/chat/chat-thread.tsx
+++ b/ui/web/src/pages/chat/chat-thread.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Circle } from "lucide-react";
 import { MessageBubble } from "@/components/chat/message-bubble";
 import { StreamingText } from "@/components/chat/streaming-text";
@@ -26,6 +27,7 @@ export function ChatThread({
   loading,
   scrollTrigger = 0,
 }: ChatThreadProps) {
+  const { t } = useTranslation("chat");
   const { ref, onScroll } = useAutoScroll<HTMLDivElement>(
     [messages.length, streamText, thinkingText, toolStream.length],
     100,
@@ -44,8 +46,8 @@ export function ChatThread({
   if (messages.length === 0 && !isRunning) {
     return (
       <div className="flex flex-1 flex-col items-center justify-center gap-2 text-muted-foreground">
-        <p className="text-lg font-medium">Start a conversation</p>
-        <p className="text-sm">Send a message to begin chatting with the agent.</p>
+        <p className="text-lg font-medium">{t("empty.title")}</p>
+        <p className="text-sm">{t("empty.description")}</p>
       </div>
     );
   }
diff --git a/ui/web/src/pages/config/config-page.tsx b/ui/web/src/pages/config/config-page.tsx
index cee80687..31ff3b27 100644
--- a/ui/web/src/pages/config/config-page.tsx
+++ b/ui/web/src/pages/config/config-page.tsx
@@ -1,4 +1,5 @@
 import { Settings, RefreshCw, ShieldAlert } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
@@ -20,6 +21,7 @@ import { BindingsSection } from "./sections/bindings-section";
 import { QuotaSection } from "./sections/quota-section";
 
 export function ConfigPage() {
+  const { t } = useTranslation("config");
   const { config, hash, loading, saving, refresh, patch } = useConfig();
   const isMobile = useIsMobile();
   const spinning = useMinLoading(loading);
@@ -28,7 +30,7 @@ export function ConfigPage() {
   if (showSkeleton) {
     return (
       <div className="p-4 sm:p-6">
-        <PageHeader title="Config" description="Gateway configuration" />
+        <PageHeader title={t("title")} description={t("description")} />
         <div className="mt-6">
           <DetailSkeleton />
         </div>
@@ -39,15 +41,15 @@ export function ConfigPage() {
   if (!config) {
     return (
       <div className="p-4 sm:p-6">
-        <PageHeader title="Config" description="Gateway configuration" />
+        <PageHeader title={t("title")} description={t("description")} />
         <div className="mt-6">
           <EmptyState
             icon={Settings}
-            title="No configuration"
-            description="Could not load gateway configuration."
+            title={t("noConfig")}
+            description={t("noConfigDescription")}
             action={
               <Button variant="outline" size="sm" onClick={refresh}>
-                Retry
+                {t("retry")}
               </Button>
             }
           />
@@ -59,8 +61,8 @@ export function ConfigPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Config"
-        description="Gateway configuration"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex items-center gap-2">
             {hash && (
@@ -69,7 +71,7 @@ export function ConfigPage() {
               </Badge>
             )}
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("common:refresh", "Refresh")}
             </Button>
           </div>
         }
@@ -77,11 +79,7 @@ export function ConfigPage() {
 
       <div className="mt-4 flex items-start gap-2 rounded-md border border-amber-500/30 bg-amber-500/5 px-3 py-2.5 text-sm text-amber-700 dark:text-amber-400">
         <ShieldAlert className="mt-0.5 h-4 w-4 shrink-0" />
-        <span>
-          This page manages gateway-level defaults. LLM providers and channels are managed on their
-          dedicated pages. Secrets shown as <code className="rounded bg-muted px-1 font-mono text-xs">***</code> are
-          stored encrypted in the database. Environment variables (if set) take highest precedence.
-        </span>
+        <span>{t("warning")}</span>
       </div>
 
       <Tabs orientation={isMobile ? "horizontal" : "vertical"} defaultValue="general" className="mt-4 items-start">
@@ -92,12 +90,12 @@ export function ConfigPage() {
             : "w-44 shrink-0 sticky top-6 rounded-lg border bg-card p-3 shadow-sm"
           }
         >
-          <TabsTrigger value="general">General</TabsTrigger>
-          <TabsTrigger value="quota">Quota</TabsTrigger>
-          <TabsTrigger value="agents">Agents</TabsTrigger>
-          <TabsTrigger value="sessions">Sessions</TabsTrigger>
-          <TabsTrigger value="tools">Tools</TabsTrigger>
-          <TabsTrigger value="advanced">Advanced</TabsTrigger>
+          <TabsTrigger value="general">{t("tabs.general")}</TabsTrigger>
+          <TabsTrigger value="quota">{t("tabs.quota")}</TabsTrigger>
+          <TabsTrigger value="agents">{t("tabs.agents")}</TabsTrigger>
+          <TabsTrigger value="sessions">{t("tabs.sessions")}</TabsTrigger>
+          <TabsTrigger value="tools">{t("tabs.tools")}</TabsTrigger>
+          <TabsTrigger value="advanced">{t("tabs.advanced")}</TabsTrigger>
         </TabsList>
 
         <TabsContent value="general" className="space-y-4">
diff --git a/ui/web/src/pages/config/sections/agents-defaults-section.tsx b/ui/web/src/pages/config/sections/agents-defaults-section.tsx
index 7dda2de1..0d3fcdf0 100644
--- a/ui/web/src/pages/config/sections/agents-defaults-section.tsx
+++ b/ui/web/src/pages/config/sections/agents-defaults-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save, ChevronDown, ChevronRight, AlertCircle } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -21,6 +22,7 @@ interface Props {
 }
 
 export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<AgentsData>(data ?? DEFAULT);
   const [dirty, setDirty] = useState(false);
   const [saveError, setSaveError] = useState<string | null>(null);
@@ -70,8 +72,8 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Agent Defaults</CardTitle>
-        <CardDescription>Default settings for all agents. Per-agent overrides are managed on the Agents page.</CardDescription>
+        <CardTitle className="text-base">{t("agents.title")}</CardTitle>
+        <CardDescription>{t("agents.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-4">
         {/* Core fields */}
@@ -80,14 +82,14 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
           onProviderChange={(v) => updateDefaults({ provider: v })}
           model={defaults.model ?? ""}
           onModelChange={(v) => updateDefaults({ model: v })}
-          providerTip="Default LLM provider for all agents. Must match a configured provider name."
-          modelTip="Default model ID for all agents. Agents can override this in their own settings."
+          providerTip={t("agents.providerTip")}
+          modelTip={t("agents.modelTip")}
           showVerify
         />
 
         <div className="grid grid-cols-4 gap-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Maximum output tokens per LLM response. Higher values allow longer responses.">Max Tokens</InfoLabel>
+            <InfoLabel tip={t("agents.maxTokensTip")}>{t("agents.maxTokens")}</InfoLabel>
             <Input
               type="number"
               value={defaults.max_tokens ?? ""}
@@ -96,7 +98,7 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Sampling temperature (0-2). Lower = more deterministic, higher = more creative.">Temperature</InfoLabel>
+            <InfoLabel tip={t("agents.temperatureTip")}>{t("agents.temperature")}</InfoLabel>
             <Input
               type="number"
               step="0.1"
@@ -108,7 +110,7 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Maximum number of tool calls per agent request before stopping.">Max Tool Iterations</InfoLabel>
+            <InfoLabel tip={t("agents.maxToolIterationsTip")}>{t("agents.maxToolIterations")}</InfoLabel>
             <Input
               type="number"
               value={defaults.max_tool_iterations ?? ""}
@@ -117,7 +119,7 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Maximum context size in tokens. Should match the model's context window limit.">Context Window</InfoLabel>
+            <InfoLabel tip={t("agents.contextWindowTip")}>{t("agents.contextWindow")}</InfoLabel>
             <Input
               type="number"
               value={defaults.context_window ?? ""}
@@ -129,7 +131,7 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
 
         <div className="grid grid-cols-2 gap-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Default filesystem workspace path for agent file operations.">Workspace</InfoLabel>
+            <InfoLabel tip={t("agents.workspaceTip")}>{t("agents.workspace")}</InfoLabel>
             <Input
               value={defaults.workspace ?? ""}
               onChange={(e) => updateDefaults({ workspace: e.target.value })}
@@ -137,7 +139,7 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="flex items-center justify-between">
-            <InfoLabel tip="When enabled, agents can only read/write files within the workspace directory.">Restrict to Workspace</InfoLabel>
+            <InfoLabel tip={t("agents.restrictToWorkspaceTip")}>{t("agents.restrictToWorkspace")}</InfoLabel>
             <Switch
               checked={defaults.restrict_to_workspace ?? false}
               onCheckedChange={(v) => updateDefaults({ restrict_to_workspace: v })}
@@ -147,28 +149,28 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
 
         {/* Collapsible sub-sections */}
         <SubSection
-          title="Subagents"
-          desc="Concurrent subagent settings"
+          title={t("agents.subagents.title")}
+          desc={t("agents.subagents.desc")}
           open={openSubs.has("subagents")}
           onToggle={() => toggleSub("subagents")}
         >
           <div className="grid grid-cols-2 gap-4">
-            <Field label="Max Concurrent" tip="Maximum subagents running at the same time." type="number" value={subagents.maxConcurrent} onChange={(v) => updateNested("subagents", { maxConcurrent: Number(v) })} placeholder="20" />
-            <Field label="Max Spawn Depth" tip="Maximum nesting depth for subagent spawning (agent → subagent → sub-subagent)." type="number" value={subagents.maxSpawnDepth} onChange={(v) => updateNested("subagents", { maxSpawnDepth: Number(v) })} placeholder="1" />
-            <Field label="Max Children/Agent" tip="Maximum child subagents a single agent can spawn." type="number" value={subagents.maxChildrenPerAgent} onChange={(v) => updateNested("subagents", { maxChildrenPerAgent: Number(v) })} placeholder="5" />
-            <Field label="Archive After (min)" tip="Auto-archive idle subagent sessions after this many minutes." type="number" value={subagents.archiveAfterMinutes} onChange={(v) => updateNested("subagents", { archiveAfterMinutes: Number(v) })} placeholder="60" />
+            <Field label={t("agents.subagents.maxConcurrent")} tip={t("agents.subagents.maxConcurrentTip")} type="number" value={subagents.maxConcurrent} onChange={(v) => updateNested("subagents", { maxConcurrent: Number(v) })} placeholder="20" />
+            <Field label={t("agents.subagents.maxSpawnDepth")} tip={t("agents.subagents.maxSpawnDepthTip")} type="number" value={subagents.maxSpawnDepth} onChange={(v) => updateNested("subagents", { maxSpawnDepth: Number(v) })} placeholder="1" />
+            <Field label={t("agents.subagents.maxChildrenPerAgent")} tip={t("agents.subagents.maxChildrenPerAgentTip")} type="number" value={subagents.maxChildrenPerAgent} onChange={(v) => updateNested("subagents", { maxChildrenPerAgent: Number(v) })} placeholder="5" />
+            <Field label={t("agents.subagents.archiveAfterMin")} tip={t("agents.subagents.archiveAfterMinTip")} type="number" value={subagents.archiveAfterMinutes} onChange={(v) => updateNested("subagents", { archiveAfterMinutes: Number(v) })} placeholder="60" />
           </div>
-          <Field label="Model Override" tip="Use a different model for subagents. Leave empty to inherit the parent agent's model." value={subagents.model} onChange={(v) => updateNested("subagents", { model: v })} placeholder="Use default" />
+          <Field label={t("agents.subagents.modelOverride")} tip={t("agents.subagents.modelOverrideTip")} value={subagents.model} onChange={(v) => updateNested("subagents", { model: v })} placeholder={t("agents.subagents.modelOverridePlaceholder")} />
         </SubSection>
 
         <SubSection
-          title="Memory"
-          desc="Embedding-based memory recall"
+          title={t("agents.memory.title")}
+          desc={t("agents.memory.desc")}
           open={openSubs.has("memory")}
           onToggle={() => toggleSub("memory")}
         >
           <div className="flex items-center justify-between">
-            <Label>Enabled</Label>
+            <Label>{t("agents.memory.enabled")}</Label>
             <Switch checked={memory.enabled !== false} onCheckedChange={(v) => updateNested("memory", { enabled: v })} />
           </div>
           <ProviderModelSelect
@@ -176,40 +178,40 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
             onProviderChange={(v) => updateNested("memory", { embedding_provider: v || undefined })}
             model={memory.embedding_model ?? ""}
             onModelChange={(v) => updateNested("memory", { embedding_model: v || undefined })}
-            providerLabel="Embedding Provider"
-            modelLabel="Embedding Model"
-            providerTip="Provider for generating text embeddings. Auto-detects from agent's main provider if empty."
-            modelTip="Embedding model name (e.g. text-embedding-3-small). Must be supported by the provider."
+            providerLabel={t("agents.memory.embeddingProvider")}
+            modelLabel={t("agents.memory.embeddingModel")}
+            providerTip={t("agents.memory.embeddingProviderTip")}
+            modelTip={t("agents.memory.embeddingModelTip")}
             providerPlaceholder="(auto)"
             modelPlaceholder="text-embedding-3-small"
           />
           <div className="grid grid-cols-2 gap-4">
-            <Field label="Max Results" tip="Maximum memory entries returned per search query." type="number" value={memory.max_results} onChange={(v) => updateNested("memory", { max_results: Number(v) })} placeholder="6" />
-            <Field label="Min Score" tip="Minimum similarity score (0-1) for memory search results. Lower = more results but less relevant." type="number" step="0.01" value={memory.min_score} onChange={(v) => updateNested("memory", { min_score: Number(v) })} placeholder="0.35" />
+            <Field label={t("agents.memory.maxResults")} tip={t("agents.memory.maxResultsTip")} type="number" value={memory.max_results} onChange={(v) => updateNested("memory", { max_results: Number(v) })} placeholder="6" />
+            <Field label={t("agents.memory.minScore")} tip={t("agents.memory.minScoreTip")} type="number" step="0.01" value={memory.min_score} onChange={(v) => updateNested("memory", { min_score: Number(v) })} placeholder="0.35" />
           </div>
         </SubSection>
 
         <SubSection
-          title="Compaction"
-          desc="Context compaction & memory flush"
+          title={t("agents.compaction.title")}
+          desc={t("agents.compaction.desc")}
           open={openSubs.has("compaction")}
           onToggle={() => toggleSub("compaction")}
         >
           <div className="grid grid-cols-2 gap-4">
-            <Field label="Reserve Tokens Floor" tip="Minimum tokens to reserve for new content after compaction. Prevents over-compaction." type="number" value={compaction.reserveTokensFloor} onChange={(v) => updateNested("compaction", { reserveTokensFloor: Number(v) })} placeholder="20000" />
-            <Field label="Max History Share" tip="Maximum fraction (0-1) of context window that conversation history can occupy before compaction triggers." type="number" step="0.05" value={compaction.maxHistoryShare} onChange={(v) => updateNested("compaction", { maxHistoryShare: Number(v) })} placeholder="0.75" />
+            <Field label={t("agents.compaction.reserveTokensFloor")} tip={t("agents.compaction.reserveTokensFloorTip")} type="number" value={compaction.reserveTokensFloor} onChange={(v) => updateNested("compaction", { reserveTokensFloor: Number(v) })} placeholder="20000" />
+            <Field label={t("agents.compaction.maxHistoryShare")} tip={t("agents.compaction.maxHistoryShareTip")} type="number" step="0.05" value={compaction.maxHistoryShare} onChange={(v) => updateNested("compaction", { maxHistoryShare: Number(v) })} placeholder="0.75" />
           </div>
         </SubSection>
 
         <SubSection
-          title="Context Pruning"
-          desc="Automatic pruning of stale context"
+          title={t("agents.pruning.title")}
+          desc={t("agents.pruning.desc")}
           open={openSubs.has("pruning")}
           onToggle={() => toggleSub("pruning")}
         >
           <div className="grid grid-cols-2 gap-4">
             <div className="grid gap-1.5">
-              <Label>Mode</Label>
+              <Label>{t("agents.pruning.mode")}</Label>
               <Select value={pruning.mode ?? "off"} onValueChange={(v) => updateNested("contextPruning", { mode: v })}>
                 <SelectTrigger><SelectValue /></SelectTrigger>
                 <SelectContent>
@@ -218,19 +220,19 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
                 </SelectContent>
               </Select>
             </div>
-            <Field label="Keep Last Assistants" tip="Number of recent assistant messages to always keep when pruning context." type="number" value={pruning.keepLastAssistants} onChange={(v) => updateNested("contextPruning", { keepLastAssistants: Number(v) })} placeholder="3" />
+            <Field label={t("agents.pruning.keepLastAssistants")} tip={t("agents.pruning.keepLastAssistantsTip")} type="number" value={pruning.keepLastAssistants} onChange={(v) => updateNested("contextPruning", { keepLastAssistants: Number(v) })} placeholder="3" />
           </div>
         </SubSection>
 
         <SubSection
-          title="Sandbox"
-          desc="Docker-based code sandbox"
+          title={t("agents.sandbox.title")}
+          desc={t("agents.sandbox.desc")}
           open={openSubs.has("sandbox")}
           onToggle={() => toggleSub("sandbox")}
         >
           <div className="grid grid-cols-2 gap-4">
             <div className="grid gap-1.5">
-              <Label>Mode</Label>
+              <Label>{t("agents.sandbox.mode")}</Label>
               <Select value={sandbox.mode ?? "off"} onValueChange={(v) => updateNested("sandbox", { mode: v })}>
                 <SelectTrigger><SelectValue /></SelectTrigger>
                 <SelectContent>
@@ -240,12 +242,12 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
                 </SelectContent>
               </Select>
             </div>
-            <Field label="Image" tip="Docker image name for the sandbox container." value={sandbox.image} onChange={(v) => updateNested("sandbox", { image: v })} placeholder="goclaw-sandbox:bookworm-slim" />
-            <Field label="Memory (MB)" tip="Memory limit in MB for the sandbox container." type="number" value={sandbox.memory_mb} onChange={(v) => updateNested("sandbox", { memory_mb: Number(v) })} placeholder="512" />
-            <Field label="CPUs" tip="CPU limit for the sandbox container (fractional values allowed)." type="number" step="0.5" value={sandbox.cpus} onChange={(v) => updateNested("sandbox", { cpus: Number(v) })} placeholder="1.0" />
-            <Field label="Timeout (sec)" tip="Maximum execution time in seconds before the sandbox is killed." type="number" value={sandbox.timeout_sec} onChange={(v) => updateNested("sandbox", { timeout_sec: Number(v) })} placeholder="300" />
+            <Field label={t("agents.sandbox.image")} tip={t("agents.sandbox.imageTip")} value={sandbox.image} onChange={(v) => updateNested("sandbox", { image: v })} placeholder="goclaw-sandbox:bookworm-slim" />
+            <Field label={t("agents.sandbox.memoryMb")} tip={t("agents.sandbox.memoryMbTip")} type="number" value={sandbox.memory_mb} onChange={(v) => updateNested("sandbox", { memory_mb: Number(v) })} placeholder="512" />
+            <Field label={t("agents.sandbox.cpus")} tip={t("agents.sandbox.cpusTip")} type="number" step="0.5" value={sandbox.cpus} onChange={(v) => updateNested("sandbox", { cpus: Number(v) })} placeholder="1.0" />
+            <Field label={t("agents.sandbox.timeoutSec")} tip={t("agents.sandbox.timeoutSecTip")} type="number" value={sandbox.timeout_sec} onChange={(v) => updateNested("sandbox", { timeout_sec: Number(v) })} placeholder="300" />
             <div className="flex items-center justify-between">
-              <Label>Network Enabled</Label>
+              <Label>{t("agents.sandbox.networkEnabled")}</Label>
               <Switch checked={sandbox.network_enabled ?? false} onCheckedChange={(v) => updateNested("sandbox", { network_enabled: v })} />
             </div>
           </div>
@@ -261,9 +263,9 @@ export function AgentsDefaultsSection({ data, onSave, saving }: Props) {
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={async () => {
               setSaveError(null);
-              try { await onSave(draft); } catch (err) { setSaveError(err instanceof Error ? err.message : "Failed to save"); }
+              try { await onSave(draft); } catch (err) { setSaveError(err instanceof Error ? err.message : t("agents.saveError")); }
             }} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/bindings-section.tsx b/ui/web/src/pages/config/sections/bindings-section.tsx
index 78dc5e0f..d1ee5111 100644
--- a/ui/web/src/pages/config/sections/bindings-section.tsx
+++ b/ui/web/src/pages/config/sections/bindings-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save, Plus, Trash2 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -27,6 +28,7 @@ interface Props {
 const EMPTY_BINDING: Binding = { agentId: "", match: { channel: "", peer: { kind: "", id: "" } } };
 
 export function BindingsSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<Binding[]>(data ?? []);
   const [dirty, setDirty] = useState(false);
 
@@ -75,23 +77,23 @@ export function BindingsSection({ data, onSave, saving }: Props) {
       <CardHeader className="pb-3">
         <div className="flex items-center justify-between">
           <div>
-            <CardTitle className="text-base">Bindings</CardTitle>
-            <CardDescription>Route channels/peers to specific agents</CardDescription>
+            <CardTitle className="text-base">{t("bindings.title")}</CardTitle>
+            <CardDescription>{t("bindings.description")}</CardDescription>
           </div>
           <Button variant="outline" size="sm" onClick={addBinding} className="gap-1.5">
-            <Plus className="h-3.5 w-3.5" /> Add
+            <Plus className="h-3.5 w-3.5" /> {t("bindings.add")}
           </Button>
         </div>
       </CardHeader>
       <CardContent className="space-y-3">
         {draft.length === 0 ? (
-          <p className="text-sm text-muted-foreground">No bindings configured. Default agent routing applies.</p>
+          <p className="text-sm text-muted-foreground">{t("bindings.noBindings")}</p>
         ) : (
           draft.map((binding, idx) => (
             <div key={idx} className="flex items-start gap-3 rounded-md border p-3">
               <div className="grid flex-1 grid-cols-4 gap-3">
                 <div className="grid gap-1">
-                  <Label className="text-xs">Agent ID</Label>
+                  <Label className="text-xs">{t("bindings.agentId")}</Label>
                   <Input
                     value={binding.agentId ?? ""}
                     onChange={(e) => updateBinding(idx, { agentId: e.target.value })}
@@ -99,7 +101,7 @@ export function BindingsSection({ data, onSave, saving }: Props) {
                   />
                 </div>
                 <div className="grid gap-1">
-                  <Label className="text-xs">Channel</Label>
+                  <Label className="text-xs">{t("bindings.channel")}</Label>
                   <Select value={binding.match?.channel ?? ""} onValueChange={(v) => updateMatch(idx, { channel: v })}>
                     <SelectTrigger>
                       <SelectValue placeholder="Any" />
@@ -115,7 +117,7 @@ export function BindingsSection({ data, onSave, saving }: Props) {
                   </Select>
                 </div>
                 <div className="grid gap-1">
-                  <Label className="text-xs">Peer Kind</Label>
+                  <Label className="text-xs">{t("bindings.peerKind")}</Label>
                   <Select value={binding.match?.peer?.kind ?? ""} onValueChange={(v) => updatePeer(idx, { kind: v })}>
                     <SelectTrigger>
                       <SelectValue placeholder="Any" />
@@ -127,7 +129,7 @@ export function BindingsSection({ data, onSave, saving }: Props) {
                   </Select>
                 </div>
                 <div className="grid gap-1">
-                  <Label className="text-xs">Peer ID</Label>
+                  <Label className="text-xs">{t("bindings.peerId")}</Label>
                   <Input
                     value={binding.match?.peer?.id ?? ""}
                     onChange={(e) => updatePeer(idx, { id: e.target.value })}
@@ -145,7 +147,7 @@ export function BindingsSection({ data, onSave, saving }: Props) {
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={() => onSave(draft)} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/channels-section.tsx b/ui/web/src/pages/config/sections/channels-section.tsx
index 594fb67f..b4f13190 100644
--- a/ui/web/src/pages/config/sections/channels-section.tsx
+++ b/ui/web/src/pages/config/sections/channels-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save, ChevronDown, ChevronRight } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -34,6 +35,7 @@ interface Props {
 }
 
 export function ChannelsSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<ChannelsData>(data ?? {});
   const [dirty, setDirty] = useState(false);
   const [expanded, setExpanded] = useState<Set<string>>(new Set());
@@ -85,12 +87,12 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Channel Defaults</CardTitle>
-        <CardDescription>Config-level channel defaults. Manage channel instances on the Channels page.</CardDescription>
+        <CardTitle className="text-base">{t("channels.title")}</CardTitle>
+        <CardDescription>{t("channels.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-2">
         {activeChannels.length === 0 ? (
-          <p className="text-sm text-muted-foreground">No channels configured.</p>
+          <p className="text-sm text-muted-foreground">{t("channels.noChannels")}</p>
         ) : (
           activeChannels.map((ch) => {
             const meta = CHANNEL_META[ch]!;
@@ -107,13 +109,13 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                   {isOpen ? <ChevronDown className="h-3.5 w-3.5" /> : <ChevronRight className="h-3.5 w-3.5" />}
                   <span className="font-medium">{meta.label}</span>
                   <Badge variant={chData.enabled ? "default" : "secondary"} className="ml-auto text-xs">
-                    {chData.enabled ? "Enabled" : "Disabled"}
+                    {chData.enabled ? t("common:enabled", "Enabled") : t("common:disabled", "Disabled")}
                   </Badge>
                 </button>
                 {isOpen && (
                   <div className="space-y-3 border-t px-3 py-3">
                     <div className="flex items-center justify-between">
-                      <Label>Enabled</Label>
+                      <Label>{t("channels.enabled")}</Label>
                       <Switch
                         checked={chData.enabled ?? false}
                         onCheckedChange={(v) => updateChannel(ch, { enabled: v })}
@@ -123,7 +125,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                     {/* Secret token */}
                     {meta.secretField && chData[meta.secretField] !== undefined && (
                       <div className="grid gap-1.5">
-                        <Label>Token</Label>
+                        <Label>{t("channels.token")}</Label>
                         <Input
                           type="password"
                           value={chData[meta.secretField] ?? ""}
@@ -132,7 +134,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                           onChange={(e) => updateChannel(ch, { [meta.secretField]: e.target.value })}
                         />
                         {isSecret(chData[meta.secretField]) && meta.secretEnv && (
-                          <p className="text-xs text-muted-foreground">Managed via {meta.secretEnv}</p>
+                          <p className="text-xs text-muted-foreground">{t("channels.managedVia", { envKey: meta.secretEnv })}</p>
                         )}
                       </div>
                     )}
@@ -141,7 +143,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                     <div className="grid grid-cols-2 gap-4">
                       {chData.dm_policy !== undefined && (
                         <div className="grid gap-1.5">
-                          <Label>DM Policy</Label>
+                          <Label>{t("channels.dmPolicy")}</Label>
                           <Select value={chData.dm_policy ?? "pairing"} onValueChange={(v) => updateChannel(ch, { dm_policy: v })}>
                             <SelectTrigger>
                               <SelectValue />
@@ -156,7 +158,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                       )}
                       {chData.group_policy !== undefined && (
                         <div className="grid gap-1.5">
-                          <Label>Group Policy</Label>
+                          <Label>{t("channels.groupPolicy")}</Label>
                           <Select value={chData.group_policy ?? "open"} onValueChange={(v) => updateChannel(ch, { group_policy: v })}>
                             <SelectTrigger>
                               <SelectValue />
@@ -174,7 +176,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                     {/* Allow from */}
                     {chData.allow_from !== undefined && (
                       <div className="grid gap-1.5">
-                        <Label>Allow From</Label>
+                        <Label>{t("channels.allowFrom")}</Label>
                         <Input
                           value={(chData.allow_from ?? []).join(", ")}
                           onChange={(e) =>
@@ -182,7 +184,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                               allow_from: e.target.value.split(",").map((s: string) => s.trim()).filter(Boolean),
                             })
                           }
-                          placeholder="Comma-separated user IDs (empty = all)"
+                          placeholder={t("channels.allowFromPlaceholder")}
                         />
                       </div>
                     )}
@@ -193,16 +195,16 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                         <div className="flex items-center gap-4">
                           <label className="flex items-center gap-2 text-sm">
                             <input type="checkbox" checked={!!chData.dm_stream} onChange={(e) => updateChannel(ch, { dm_stream: e.target.checked })} />
-                            DM Streaming
+                            {t("channels.dmStreaming")}
                           </label>
                           <label className="flex items-center gap-2 text-sm">
                             <input type="checkbox" checked={!!chData.group_stream} onChange={(e) => updateChannel(ch, { group_stream: e.target.checked })} />
-                            Group Streaming
+                            {t("channels.groupStreaming")}
                           </label>
                         </div>
                         {chData.reaction_level !== undefined && (
                           <div className="grid gap-1.5">
-                            <Label>Reaction Level</Label>
+                            <Label>{t("channels.reactionLevel")}</Label>
                             <Select value={chData.reaction_level ?? "off"} onValueChange={(v) => updateChannel(ch, { reaction_level: v })}>
                               <SelectTrigger><SelectValue /></SelectTrigger>
                               <SelectContent>
@@ -219,7 +221,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
                     {/* Feishu-specific */}
                     {ch === "feishu" && chData.connection_mode !== undefined && (
                       <div className="grid gap-1.5">
-                        <Label>Connection Mode</Label>
+                        <Label>{t("channels.connectionMode")}</Label>
                         <Select value={chData.connection_mode ?? "websocket"} onValueChange={(v) => updateChannel(ch, { connection_mode: v })}>
                           <SelectTrigger><SelectValue /></SelectTrigger>
                           <SelectContent>
@@ -239,7 +241,7 @@ export function ChannelsSection({ data, onSave, saving }: Props) {
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={handleSave} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/cron-section.tsx b/ui/web/src/pages/config/sections/cron-section.tsx
index 5fc4492b..628ea152 100644
--- a/ui/web/src/pages/config/sections/cron-section.tsx
+++ b/ui/web/src/pages/config/sections/cron-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
@@ -20,6 +21,7 @@ interface Props {
 }
 
 export function CronSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<CronData>(data ?? DEFAULT);
   const [dirty, setDirty] = useState(false);
 
@@ -38,13 +40,13 @@ export function CronSection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Cron</CardTitle>
-        <CardDescription>Cron job retry settings</CardDescription>
+        <CardTitle className="text-base">{t("cron.title")}</CardTitle>
+        <CardDescription>{t("cron.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-4">
         <div className="grid grid-cols-3 gap-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Maximum number of retry attempts for failed cron jobs before giving up.">Max Retries</InfoLabel>
+            <InfoLabel tip={t("cron.maxRetriesTip")}>{t("cron.maxRetries")}</InfoLabel>
             <Input
               type="number"
               value={draft.max_retries ?? ""}
@@ -54,7 +56,7 @@ export function CronSection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Initial delay between retries with exponential backoff. Go duration format (e.g. 2s, 500ms).">Base Delay</InfoLabel>
+            <InfoLabel tip={t("cron.baseDelayTip")}>{t("cron.baseDelay")}</InfoLabel>
             <Input
               value={draft.retry_base_delay ?? ""}
               onChange={(e) => update({ retry_base_delay: e.target.value })}
@@ -62,7 +64,7 @@ export function CronSection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Maximum delay cap for exponential backoff. Retries won't wait longer than this. Go duration format.">Max Delay</InfoLabel>
+            <InfoLabel tip={t("cron.maxDelayTip")}>{t("cron.maxDelay")}</InfoLabel>
             <Input
               value={draft.retry_max_delay ?? ""}
               onChange={(e) => update({ retry_max_delay: e.target.value })}
@@ -74,7 +76,7 @@ export function CronSection({ data, onSave, saving }: Props) {
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={() => onSave(draft)} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/gateway-section.tsx b/ui/web/src/pages/config/sections/gateway-section.tsx
index 98c82e1b..017526c5 100644
--- a/ui/web/src/pages/config/sections/gateway-section.tsx
+++ b/ui/web/src/pages/config/sections/gateway-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Switch } from "@/components/ui/switch";
@@ -34,6 +35,7 @@ interface Props {
 }
 
 export function GatewaySection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<GatewayData>(data ?? DEFAULT);
   const [dirty, setDirty] = useState(false);
 
@@ -61,13 +63,13 @@ export function GatewaySection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Gateway</CardTitle>
-        <CardDescription>WebSocket & HTTP server settings, security</CardDescription>
+        <CardTitle className="text-base">{t("gateway.title")}</CardTitle>
+        <CardDescription>{t("gateway.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-4">
         <div className="grid grid-cols-1 gap-4 sm:grid-cols-3">
           <div className="grid gap-1.5">
-            <InfoLabel tip="IP address to bind the server. Use 0.0.0.0 to accept connections from any interface.">Host</InfoLabel>
+            <InfoLabel tip={t("gateway.hostTip")}>{t("gateway.host")}</InfoLabel>
             <Input
               value={draft.host ?? ""}
               onChange={(e) => update({ host: e.target.value })}
@@ -75,7 +77,7 @@ export function GatewaySection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="TCP port for the WebSocket and HTTP server.">Port</InfoLabel>
+            <InfoLabel tip={t("gateway.portTip")}>{t("gateway.port")}</InfoLabel>
             <Input
               type="number"
               value={draft.port ?? ""}
@@ -84,7 +86,7 @@ export function GatewaySection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Bearer token for authenticating WebSocket and API connections. Managed via GOCLAW_GATEWAY_TOKEN env var.">Token</InfoLabel>
+            <InfoLabel tip={t("gateway.tokenTip")}>{t("gateway.token")}</InfoLabel>
             <Input
               type="password"
               value={draft.token ?? ""}
@@ -93,33 +95,33 @@ export function GatewaySection({ data, onSave, saving }: Props) {
               onChange={(e) => update({ token: e.target.value })}
             />
             {isSecret(draft.token) && (
-              <p className="text-xs text-muted-foreground">Managed via GOCLAW_GATEWAY_TOKEN</p>
+              <p className="text-xs text-muted-foreground">{t("gateway.tokenManaged")}</p>
             )}
           </div>
         </div>
 
         <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Sender IDs with admin privileges. These users bypass rate limits and can manage configuration.">Owner IDs</InfoLabel>
+            <InfoLabel tip={t("gateway.ownerIdsTip")}>{t("gateway.ownerIds")}</InfoLabel>
             <TagInput
               value={draft.owner_ids ?? []}
               onChange={(v) => update({ owner_ids: v })}
-              placeholder="Type ID and press Enter..."
+              placeholder={t("gateway.ownerIdsPlaceholder")}
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="CORS allowed origins for the HTTP API. Empty means all origins are allowed.">Allowed Origins</InfoLabel>
+            <InfoLabel tip={t("gateway.allowedOriginsTip")}>{t("gateway.allowedOrigins")}</InfoLabel>
             <TagInput
               value={draft.allowed_origins ?? []}
               onChange={(v) => update({ allowed_origins: v })}
-              placeholder="Type origin and press Enter..."
+              placeholder={t("gateway.allowedOriginsPlaceholder")}
             />
           </div>
         </div>
 
         <div className="grid grid-cols-2 gap-4 sm:grid-cols-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Maximum characters per inbound message. Messages exceeding this are rejected.">Max Message Chars</InfoLabel>
+            <InfoLabel tip={t("gateway.maxMessageCharsTip")}>{t("gateway.maxMessageChars")}</InfoLabel>
             <Input
               type="number"
               value={draft.max_message_chars ?? ""}
@@ -128,7 +130,7 @@ export function GatewaySection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Requests per minute per sender. 0 = no limit. Prevents abuse from individual users.">Rate Limit (RPM)</InfoLabel>
+            <InfoLabel tip={t("gateway.rateLimitRpmTip")}>{t("gateway.rateLimitRpm")}</InfoLabel>
             <Input
               type="number"
               value={draft.rate_limit_rpm ?? ""}
@@ -138,7 +140,7 @@ export function GatewaySection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Delay in ms before processing messages. Groups rapid messages into one request. -1 = disabled.">Inbound Debounce (ms)</InfoLabel>
+            <InfoLabel tip={t("gateway.inboundDebounceMsTip")}>{t("gateway.inboundDebounceMs")}</InfoLabel>
             <Input
               type="number"
               value={draft.inbound_debounce_ms ?? ""}
@@ -148,7 +150,7 @@ export function GatewaySection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Action when prompt injection is detected. Off = disabled, Log = log only, Warn = add warning to prompt, Block = reject.">Injection Action</InfoLabel>
+            <InfoLabel tip={t("gateway.injectionActionTip")}>{t("gateway.injectionAction")}</InfoLabel>
             <Select value={draft.injection_action ?? "warn"} onValueChange={(v) => update({ injection_action: v })}>
               <SelectTrigger>
                 <SelectValue />
@@ -162,7 +164,7 @@ export function GatewaySection({ data, onSave, saving }: Props) {
             </Select>
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Deliver intermediate assistant text to non-streaming channels during tool iterations. Each assistant block is sent before tool execution.">Block Reply</InfoLabel>
+            <InfoLabel tip={t("gateway.blockReplyTip")}>{t("gateway.blockReply")}</InfoLabel>
             <div className="flex items-center h-9">
               <Switch checked={draft.block_reply ?? false} onCheckedChange={(v) => update({ block_reply: v })} />
             </div>
@@ -172,7 +174,7 @@ export function GatewaySection({ data, onSave, saving }: Props) {
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={handleSave} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/providers-section.tsx b/ui/web/src/pages/config/sections/providers-section.tsx
index ac4f7cd2..7a857804 100644
--- a/ui/web/src/pages/config/sections/providers-section.tsx
+++ b/ui/web/src/pages/config/sections/providers-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save, ChevronDown, ChevronRight } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -37,6 +38,7 @@ interface Props {
 }
 
 export function ProvidersSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<ProvidersData>(data ?? {});
   const [dirty, setDirty] = useState(false);
   const [expanded, setExpanded] = useState<Set<string>>(new Set());
@@ -85,12 +87,12 @@ export function ProvidersSection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">LLM Provider Defaults</CardTitle>
-        <CardDescription>Config-level provider settings. Manage providers on the Providers page.</CardDescription>
+        <CardTitle className="text-base">{t("providers.title")}</CardTitle>
+        <CardDescription>{t("providers.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-2">
         {activeProviders.length === 0 ? (
-          <p className="text-sm text-muted-foreground">No providers configured.</p>
+          <p className="text-sm text-muted-foreground">{t("providers.noProviders")}</p>
         ) : (
           activeProviders.map((p) => {
             const entry = draft[p.key] ?? {};
@@ -111,7 +113,7 @@ export function ProvidersSection({ data, onSave, saving }: Props) {
                 {isOpen && (
                   <div className="space-y-3 border-t px-3 py-3">
                     <div className="grid gap-1.5">
-                      <Label>API Key</Label>
+                      <Label>{t("providers.apiKey")}</Label>
                       <Input
                         type="password"
                         value={entry.api_key ?? ""}
@@ -120,15 +122,15 @@ export function ProvidersSection({ data, onSave, saving }: Props) {
                         onChange={(e) => updateProvider(p.key, { api_key: e.target.value })}
                       />
                       {isSecret(entry.api_key) && (
-                        <p className="text-xs text-muted-foreground">Managed via {p.envKey}</p>
+                        <p className="text-xs text-muted-foreground">{t("providers.managedVia", { envKey: p.envKey })}</p>
                       )}
                     </div>
                     <div className="grid gap-1.5">
-                      <Label>API Base URL</Label>
+                      <Label>{t("providers.apiBaseUrl")}</Label>
                       <Input
                         value={entry.api_base ?? ""}
                         onChange={(e) => updateProvider(p.key, { api_base: e.target.value })}
-                        placeholder="Default endpoint"
+                        placeholder={t("providers.apiBaseUrlPlaceholder")}
                       />
                     </div>
                   </div>
@@ -141,7 +143,7 @@ export function ProvidersSection({ data, onSave, saving }: Props) {
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={handleSave} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/quota-section.tsx b/ui/web/src/pages/config/sections/quota-section.tsx
index 643695c1..3c9f5a90 100644
--- a/ui/web/src/pages/config/sections/quota-section.tsx
+++ b/ui/web/src/pages/config/sections/quota-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save, Plus, Trash2 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Switch } from "@/components/ui/switch";
@@ -53,10 +54,11 @@ function QuotaWindowInputs({
   value: QuotaWindow;
   onChange: (v: QuotaWindow) => void;
 }) {
+  const { t } = useTranslation("config");
   return (
     <div className="grid grid-cols-3 gap-3">
       <div className="grid gap-1.5">
-        <InfoLabel tip="Max requests per hour (0 = unlimited)">Hour</InfoLabel>
+        <InfoLabel tip={t("quota.hourTip")}>{t("quota.hour")}</InfoLabel>
         <Input
           type="number"
           min={0}
@@ -65,7 +67,7 @@ function QuotaWindowInputs({
         />
       </div>
       <div className="grid gap-1.5">
-        <InfoLabel tip="Max requests per day (0 = unlimited)">Day</InfoLabel>
+        <InfoLabel tip={t("quota.dayTip")}>{t("quota.day")}</InfoLabel>
         <Input
           type="number"
           min={0}
@@ -74,7 +76,7 @@ function QuotaWindowInputs({
         />
       </div>
       <div className="grid gap-1.5">
-        <InfoLabel tip="Max requests per week (0 = unlimited)">Week</InfoLabel>
+        <InfoLabel tip={t("quota.weekTip")}>{t("quota.week")}</InfoLabel>
         <Input
           type="number"
           min={0}
@@ -130,6 +132,8 @@ function OverridesTable({
     onChange({ ...entries, [key]: window });
   };
 
+  const { t } = useTranslation("config");
+
   return (
     <div className="space-y-2">
       <InfoLabel tip={tip}>{label}</InfoLabel>
@@ -138,7 +142,7 @@ function OverridesTable({
           <div className="flex items-end gap-2 min-w-[420px]">
             <div className="grid gap-1.5 min-w-[180px]">
               {i === 0 && (
-                <span className="text-xs text-muted-foreground">Key</span>
+                <span className="text-xs text-muted-foreground">{t("quota.keyLabel")}</span>
               )}
               {options ? (
                 <Select
@@ -174,7 +178,7 @@ function OverridesTable({
             </div>
             <div className="grid gap-1.5 w-20">
               {i === 0 && (
-                <span className="text-xs text-muted-foreground">Hour</span>
+                <span className="text-xs text-muted-foreground">{t("quota.hour")}</span>
               )}
               <Input
                 type="number"
@@ -190,7 +194,7 @@ function OverridesTable({
             </div>
             <div className="grid gap-1.5 w-20">
               {i === 0 && (
-                <span className="text-xs text-muted-foreground">Day</span>
+                <span className="text-xs text-muted-foreground">{t("quota.day")}</span>
               )}
               <Input
                 type="number"
@@ -206,7 +210,7 @@ function OverridesTable({
             </div>
             <div className="grid gap-1.5 w-20">
               {i === 0 && (
-                <span className="text-xs text-muted-foreground">Week</span>
+                <span className="text-xs text-muted-foreground">{t("quota.week")}</span>
               )}
               <Input
                 type="number"
@@ -238,7 +242,7 @@ function OverridesTable({
         >
           <SelectTrigger className="w-auto gap-1.5" size="sm">
             <Plus className="h-3.5 w-3.5" />
-            <SelectValue placeholder="Add override" />
+            <SelectValue placeholder={t("quota.addOverride")} />
           </SelectTrigger>
           <SelectContent>
             {availableOptions && availableOptions.length > 0 ? (
@@ -249,14 +253,14 @@ function OverridesTable({
               ))
             ) : (
               <SelectItem value="__none__" disabled>
-                All options added
+                {t("quota.allOptionsAdded")}
               </SelectItem>
             )}
           </SelectContent>
         </Select>
       ) : (
         <Button variant="outline" size="sm" onClick={() => addRow()} className="gap-1.5">
-          <Plus className="h-3.5 w-3.5" /> Add override
+          <Plus className="h-3.5 w-3.5" /> {t("quota.addOverride")}
         </Button>
       )}
     </div>
@@ -264,6 +268,7 @@ function OverridesTable({
 }
 
 export function QuotaSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<QuotaData>(
     data?.quota ?? DEFAULT_QUOTA
   );
@@ -309,16 +314,12 @@ export function QuotaSection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Quota Limits</CardTitle>
-        <CardDescription>
-          Per-user/group request quotas. Limits are enforced per time window
-          (hour/day/week). Config merge priority: Group &gt; Channel &gt;
-          Provider &gt; Default.
-        </CardDescription>
+        <CardTitle className="text-base">{t("quota.title")}</CardTitle>
+        <CardDescription>{t("quota.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-4">
         <div className="flex items-center justify-between">
-          <InfoLabel tip="Enable request quota enforcement">Enabled</InfoLabel>
+          <InfoLabel tip={t("quota.enabledTip")}>{t("quota.enabled")}</InfoLabel>
           <Switch
             checked={draft.enabled}
             onCheckedChange={(v) => update({ enabled: v })}
@@ -328,8 +329,8 @@ export function QuotaSection({ data, onSave, saving }: Props) {
         {draft.enabled && (
           <>
             <div className="space-y-2">
-              <InfoLabel tip="Default limits applied to all users/groups unless overridden">
-                Default Limits
+              <InfoLabel tip={t("quota.defaultLimitsTip")}>
+                {t("quota.defaultLimits")}
               </InfoLabel>
               <QuotaWindowInputs
                 value={draft.default}
@@ -338,29 +339,29 @@ export function QuotaSection({ data, onSave, saving }: Props) {
             </div>
 
             <OverridesTable
-              label="Provider Overrides"
-              tip="Per-provider quota limits (e.g., anthropic, openai)"
+              label={t("quota.providerOverrides")}
+              tip={t("quota.providerOverridesTip")}
               entries={draft.providers ?? {}}
               onChange={(v) => update({ providers: v })}
-              keyPlaceholder="Select provider"
+              keyPlaceholder={t("quota.selectProvider")}
               options={providerOptions}
             />
 
             <OverridesTable
-              label="Channel Overrides"
-              tip="Per-channel quota limits (e.g., telegram, discord)"
+              label={t("quota.channelOverrides")}
+              tip={t("quota.channelOverridesTip")}
               entries={draft.channels ?? {}}
               onChange={(v) => update({ channels: v })}
-              keyPlaceholder="Select channel"
+              keyPlaceholder={t("quota.selectChannel")}
               options={channelOptions}
             />
 
             <OverridesTable
-              label="Group/User Overrides"
-              tip="Per-user or group quota limits (e.g., group:telegram:-100123)"
+              label={t("quota.groupOverrides")}
+              tip={t("quota.groupOverridesTip")}
               entries={draft.groups ?? {}}
               onChange={(v) => update({ groups: v })}
-              keyPlaceholder="Select group"
+              keyPlaceholder={t("quota.selectGroup")}
               options={groupOptions.length > 0 ? groupOptions : undefined}
             />
           </>
@@ -375,7 +376,7 @@ export function QuotaSection({ data, onSave, saving }: Props) {
               className="gap-1.5"
             >
               <Save className="h-3.5 w-3.5" />{" "}
-              {saving ? "Saving..." : "Save"}
+              {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/sessions-section.tsx b/ui/web/src/pages/config/sections/sessions-section.tsx
index 61201bc1..21610cfd 100644
--- a/ui/web/src/pages/config/sections/sessions-section.tsx
+++ b/ui/web/src/pages/config/sections/sessions-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
@@ -21,6 +22,7 @@ interface Props {
 }
 
 export function SessionsSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<SessionsData>(data ?? DEFAULT);
   const [dirty, setDirty] = useState(false);
 
@@ -39,13 +41,13 @@ export function SessionsSection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Sessions</CardTitle>
-        <CardDescription>Session scoping settings. Sessions are stored in PostgreSQL.</CardDescription>
+        <CardTitle className="text-base">{t("sessions.title")}</CardTitle>
+        <CardDescription>{t("sessions.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-4">
         <div className="grid grid-cols-1 gap-4 sm:grid-cols-3">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Session isolation level. Per Sender = each user gets their own session. Global = all users share one session.">Scope</InfoLabel>
+            <InfoLabel tip={t("sessions.scopeTip")}>{t("sessions.scope")}</InfoLabel>
             <Select value={draft.scope ?? "per-sender"} onValueChange={(v) => update({ scope: v })}>
               <SelectTrigger>
                 <SelectValue />
@@ -57,7 +59,7 @@ export function SessionsSection({ data, onSave, saving }: Props) {
             </Select>
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="How DM sessions are scoped. Controls session isolation for direct messages across different channels and accounts.">DM Scope</InfoLabel>
+            <InfoLabel tip={t("sessions.dmScopeTip")}>{t("sessions.dmScope")}</InfoLabel>
             <Select value={draft.dm_scope ?? "per-channel-peer"} onValueChange={(v) => update({ dm_scope: v })}>
               <SelectTrigger>
                 <SelectValue />
@@ -75,7 +77,7 @@ export function SessionsSection({ data, onSave, saving }: Props) {
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={() => onSave(draft)} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/telemetry-section.tsx b/ui/web/src/pages/config/sections/telemetry-section.tsx
index 217314ab..5ccecff4 100644
--- a/ui/web/src/pages/config/sections/telemetry-section.tsx
+++ b/ui/web/src/pages/config/sections/telemetry-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Switch } from "@/components/ui/switch";
@@ -26,6 +27,7 @@ interface Props {
 }
 
 export function TelemetrySection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<TelemetryData>(data ?? DEFAULT);
   const [headers, setHeaders] = useState<Record<string, string>>({});
   const [dirty, setDirty] = useState(false);
@@ -50,18 +52,18 @@ export function TelemetrySection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Telemetry</CardTitle>
-        <CardDescription>OpenTelemetry export configuration</CardDescription>
+        <CardTitle className="text-base">{t("telemetry.title")}</CardTitle>
+        <CardDescription>{t("telemetry.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-4">
         <div className="flex items-center justify-between">
-          <InfoLabel tip="Enable OpenTelemetry export of LLM call traces and spans.">Enabled</InfoLabel>
+          <InfoLabel tip={t("telemetry.enabledTip")}>{t("telemetry.enabled")}</InfoLabel>
           <Switch checked={draft.enabled ?? false} onCheckedChange={(v) => update({ enabled: v })} />
         </div>
 
         <div className="grid grid-cols-2 gap-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="OTel collector endpoint address (host:port). E.g. localhost:4317 for gRPC or localhost:4318 for HTTP.">Endpoint</InfoLabel>
+            <InfoLabel tip={t("telemetry.endpointTip")}>{t("telemetry.endpoint")}</InfoLabel>
             <Input
               value={draft.endpoint ?? ""}
               onChange={(e) => update({ endpoint: e.target.value })}
@@ -69,7 +71,7 @@ export function TelemetrySection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Transport protocol for exporting traces. gRPC is recommended for most setups.">Protocol</InfoLabel>
+            <InfoLabel tip={t("telemetry.protocolTip")}>{t("telemetry.protocol")}</InfoLabel>
             <Select value={draft.protocol ?? "grpc"} onValueChange={(v) => update({ protocol: v })}>
               <SelectTrigger>
                 <SelectValue />
@@ -84,7 +86,7 @@ export function TelemetrySection({ data, onSave, saving }: Props) {
 
         <div className="grid grid-cols-2 gap-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Service name reported in trace spans. Useful for distinguishing multiple gateway instances.">Service Name</InfoLabel>
+            <InfoLabel tip={t("telemetry.serviceNameTip")}>{t("telemetry.serviceName")}</InfoLabel>
             <Input
               value={draft.service_name ?? ""}
               onChange={(e) => update({ service_name: e.target.value })}
@@ -92,26 +94,26 @@ export function TelemetrySection({ data, onSave, saving }: Props) {
             />
           </div>
           <div className="flex items-center justify-between">
-            <InfoLabel tip="Disable TLS for the connection to the OTel collector. Use only for local/trusted networks.">Insecure (no TLS)</InfoLabel>
+            <InfoLabel tip={t("telemetry.insecureTip")}>{t("telemetry.insecure")}</InfoLabel>
             <Switch checked={draft.insecure ?? false} onCheckedChange={(v) => update({ insecure: v })} />
           </div>
         </div>
 
         <div className="grid gap-1.5">
-          <InfoLabel tip="Additional HTTP headers sent with each export request. Useful for authentication tokens or routing metadata.">Headers</InfoLabel>
+          <InfoLabel tip={t("telemetry.headersTip")}>{t("telemetry.headers")}</InfoLabel>
           <KeyValueEditor
             value={headers}
             onChange={(v) => { setHeaders(v); setDirty(true); }}
-            keyPlaceholder="Header name"
-            valuePlaceholder="Header value"
-            addLabel="Add Header"
+            keyPlaceholder={t("telemetry.headerKeyPlaceholder")}
+            valuePlaceholder={t("telemetry.headerValuePlaceholder")}
+            addLabel={t("telemetry.addHeader")}
           />
         </div>
 
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={handleSave} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/tools-section.tsx b/ui/web/src/pages/config/sections/tools-section.tsx
index 68799a12..02aa6af2 100644
--- a/ui/web/src/pages/config/sections/tools-section.tsx
+++ b/ui/web/src/pages/config/sections/tools-section.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { Save } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -23,6 +24,7 @@ interface Props {
 }
 
 export function ToolsSection({ data, onSave, saving }: Props) {
+  const { t } = useTranslation("config");
   const [draft, setDraft] = useState<ToolsData>(data ?? DEFAULT);
   const [dirty, setDirty] = useState(false);
 
@@ -56,17 +58,17 @@ export function ToolsSection({ data, onSave, saving }: Props) {
   return (
     <Card>
       <CardHeader className="pb-3">
-        <CardTitle className="text-base">Tools</CardTitle>
-        <CardDescription>Tool policies, exec approval, web search, browser</CardDescription>
+        <CardTitle className="text-base">{t("tools.title")}</CardTitle>
+        <CardDescription>{t("tools.description")}</CardDescription>
       </CardHeader>
       <CardContent className="space-y-4">
         {/* Profile & Lists */}
         <div className="grid grid-cols-2 gap-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Tool profile preset. Minimal = basic tools, Coding = filesystem + exec, Messaging = channels, Full = all tools enabled.">Profile</InfoLabel>
+            <InfoLabel tip={t("tools.profileTip")}>{t("tools.profile")}</InfoLabel>
             <Select value={draft.profile ?? ""} onValueChange={(v) => update({ profile: v })}>
               <SelectTrigger>
-                <SelectValue placeholder="Select profile" />
+                <SelectValue placeholder={t("tools.profilePlaceholder")} />
               </SelectTrigger>
               <SelectContent>
                 <SelectItem value="minimal">Minimal</SelectItem>
@@ -77,7 +79,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
             </Select>
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Maximum tool executions per hour across all tools. 0 = no limit.">Rate Limit (per hour)</InfoLabel>
+            <InfoLabel tip={t("tools.rateLimitPerHourTip")}>{t("tools.rateLimitPerHour")}</InfoLabel>
             <Input
               type="number"
               value={draft.rate_limit_per_hour ?? ""}
@@ -90,34 +92,34 @@ export function ToolsSection({ data, onSave, saving }: Props) {
 
         <div className="space-y-4">
           <div className="grid gap-1.5">
-            <InfoLabel tip="Explicit whitelist of tool names. Only these tools will be available (overrides profile).">Allow</InfoLabel>
+            <InfoLabel tip={t("tools.allowTip")}>{t("tools.allow")}</InfoLabel>
             <ToolNameSelect
               value={draft.allow ?? []}
               onChange={(v) => { update({ allow: v }); }}
-              placeholder="Select tools to allow..."
+              placeholder={t("tools.allowPlaceholder")}
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Blacklist of tool names. These tools are disabled regardless of profile or allow list.">Deny</InfoLabel>
+            <InfoLabel tip={t("tools.denyTip")}>{t("tools.deny")}</InfoLabel>
             <ToolNameSelect
               value={draft.deny ?? []}
               onChange={(v) => { update({ deny: v }); }}
-              placeholder="Select tools to deny..."
+              placeholder={t("tools.denyPlaceholder")}
             />
           </div>
           <div className="grid gap-1.5">
-            <InfoLabel tip="Additional tools to enable on top of the profile. Additive to the profile's default set.">Also Allow</InfoLabel>
+            <InfoLabel tip={t("tools.alsoAllowTip")}>{t("tools.alsoAllow")}</InfoLabel>
             <ToolNameSelect
               value={draft.alsoAllow ?? []}
               onChange={(v) => { update({ alsoAllow: v }); }}
-              placeholder="Select additional tools..."
+              placeholder={t("tools.alsoAllowPlaceholder")}
             />
           </div>
         </div>
 
         <div className="flex items-center justify-between">
           <div>
-            <InfoLabel tip="Automatically redact API keys, tokens, and other credentials from tool output before sending to the LLM.">Scrub Credentials</InfoLabel>
+            <InfoLabel tip={t("tools.scrubCredentialsTip")}>{t("tools.scrubCredentials")}</InfoLabel>
           </div>
           <Switch
             checked={draft.scrub_credentials !== false}
@@ -129,10 +131,10 @@ export function ToolsSection({ data, onSave, saving }: Props) {
 
         {/* Exec Approval */}
         <div>
-          <h4 className="mb-3 text-sm font-medium">Exec Approval</h4>
+          <h4 className="mb-3 text-sm font-medium">{t("tools.execApproval")}</h4>
           <div className="grid grid-cols-2 gap-4">
             <div className="grid gap-1.5">
-              <InfoLabel tip="Security level for shell command execution. Deny = no exec, Allowlist = only matching patterns, Full = allow all commands.">Security</InfoLabel>
+              <InfoLabel tip={t("tools.execSecurityTip")}>{t("tools.execSecurity")}</InfoLabel>
               <Select value={exec.security ?? "full"} onValueChange={(v) => updateNested("execApproval", { security: v })}>
                 <SelectTrigger>
                   <SelectValue />
@@ -145,7 +147,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
               </Select>
             </div>
             <div className="grid gap-1.5">
-              <InfoLabel tip="When to ask the user for approval before executing a command. Off = never ask, On Miss = ask if not in allowlist, Always = always ask.">Ask Mode</InfoLabel>
+              <InfoLabel tip={t("tools.execAskModeTip")}>{t("tools.execAskMode")}</InfoLabel>
               <Select value={exec.ask ?? "off"} onValueChange={(v) => updateNested("execApproval", { ask: v })}>
                 <SelectTrigger>
                   <SelectValue />
@@ -160,7 +162,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
           </div>
           {exec.security === "allowlist" && (
             <div className="mt-3 grid gap-1.5">
-              <Label>Allowlist (glob patterns)</Label>
+              <Label>{t("tools.execAllowlistLabel")}</Label>
               <Textarea
                 value={(exec.allowlist ?? []).join("\n")}
                 onChange={(e) =>
@@ -179,7 +181,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
 
         {/* Web Search */}
         <div>
-          <h4 className="mb-3 text-sm font-medium">Web Search</h4>
+          <h4 className="mb-3 text-sm font-medium">{t("tools.webSearch")}</h4>
           <div className="grid grid-cols-2 gap-4">
             <div className="space-y-2">
               <div className="flex items-center justify-between">
@@ -190,7 +192,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
                 />
               </div>
               <div className="grid gap-1.5">
-                <Label className="text-xs text-muted-foreground">Max Results</Label>
+                <Label className="text-xs text-muted-foreground">{t("tools.maxResults")}</Label>
                 <Input
                   type="number"
                   value={ddg.max_results ?? ""}
@@ -209,7 +211,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
                 />
               </div>
               <div className="grid gap-1.5">
-                <Label className="text-xs text-muted-foreground">Max Results</Label>
+                <Label className="text-xs text-muted-foreground">{t("tools.maxResults")}</Label>
                 <Input
                   type="number"
                   value={brave.max_results ?? ""}
@@ -226,10 +228,10 @@ export function ToolsSection({ data, onSave, saving }: Props) {
 
         {/* Web Fetch */}
         <div>
-          <h4 className="mb-3 text-sm font-medium">Web Fetch</h4>
+          <h4 className="mb-3 text-sm font-medium">{t("tools.webFetch")}</h4>
           <div className="grid gap-3">
             <div className="grid gap-1.5 max-w-xs">
-              <InfoLabel tip="Domain policy for URL fetching. Allow All = fetch any domain. Allowlist = only fetch from specified domains.">Policy</InfoLabel>
+              <InfoLabel tip={t("tools.webFetchPolicyTip")}>{t("tools.webFetchPolicy")}</InfoLabel>
               <Select
                 value={webFetch.policy ?? "allow_all"}
                 onValueChange={(v) => updateNested("web_fetch", { ...webFetch, policy: v })}
@@ -245,7 +247,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
             </div>
             {webFetch.policy === "allowlist" && (
               <div className="grid gap-1.5">
-                <Label>Allowed Domains (one per line, supports *.example.com)</Label>
+                <Label>{t("tools.allowedDomains")}</Label>
                 <Textarea
                   value={(webFetch.allowed_domains ?? []).join("\n")}
                   onChange={(e) =>
@@ -260,7 +262,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
               </div>
             )}
             <div className="grid gap-1.5">
-              <InfoLabel tip="Domains that are always blocked regardless of policy mode. Useful for preventing info-leak sites (IP lookup, etc.).">Blocked Domains (one per line, supports *.example.com)</InfoLabel>
+              <InfoLabel tip={t("tools.blockedDomainsTip")}>{t("tools.blockedDomains")}</InfoLabel>
               <Textarea
                 value={(webFetch.blocked_domains ?? []).join("\n")}
                 onChange={(e) =>
@@ -280,17 +282,17 @@ export function ToolsSection({ data, onSave, saving }: Props) {
 
         {/* Browser */}
         <div>
-          <h4 className="mb-3 text-sm font-medium">Browser</h4>
+          <h4 className="mb-3 text-sm font-medium">{t("tools.browser")}</h4>
           <div className="flex gap-6">
             <div className="flex items-center gap-2">
-              <Label>Enabled</Label>
+              <Label>{t("tools.browserEnabled")}</Label>
               <Switch
                 checked={browser.enabled !== false}
                 onCheckedChange={(v) => updateNested("browser", { enabled: v })}
               />
             </div>
             <div className="flex items-center gap-2">
-              <Label>Headless</Label>
+              <Label>{t("tools.browserHeadless")}</Label>
               <Switch
                 checked={browser.headless !== false}
                 onCheckedChange={(v) => updateNested("browser", { headless: v })}
@@ -302,7 +304,7 @@ export function ToolsSection({ data, onSave, saving }: Props) {
         {dirty && (
           <div className="flex justify-end pt-2">
             <Button size="sm" onClick={() => onSave(draft)} disabled={saving} className="gap-1.5">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         )}
diff --git a/ui/web/src/pages/config/sections/tts-section.tsx b/ui/web/src/pages/config/sections/tts-section.tsx
index 9f169878..089dae29 100644
--- a/ui/web/src/pages/config/sections/tts-section.tsx
+++ b/ui/web/src/pages/config/sections/tts-section.tsx
@@ -1,5 +1,6 @@
 import { Link } from "react-router";
 import { ExternalLink } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Badge } from "@/components/ui/badge";
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
 import { ROUTES } from "@/lib/constants";
@@ -10,6 +11,8 @@ interface Props {
 }
 
 export function TtsSection({ data }: Props) {
+  const { t } = useTranslation("config");
+
   if (!data) return null;
 
   const provider = data.provider as string | undefined;
@@ -19,15 +22,15 @@ export function TtsSection({ data }: Props) {
     <Card>
       <CardHeader className="pb-3">
         <div className="flex items-center gap-2">
-          <CardTitle className="text-base">Text-to-Speech</CardTitle>
+          <CardTitle className="text-base">{t("tts.title")}</CardTitle>
           <Badge variant={provider ? "default" : "secondary"}>
-            {provider ? "Configured" : "Disabled"}
+            {provider ? t("tts.configured") : t("tts.disabled")}
           </Badge>
         </div>
         <CardDescription>
           {provider
-            ? `Provider: ${provider}, Auto: ${auto ?? "off"}`
-            : "No TTS provider configured"}
+            ? t("tts.providerInfo", { provider, auto: auto ?? "off" })
+            : t("tts.noProvider")}
         </CardDescription>
       </CardHeader>
       <CardContent>
@@ -35,7 +38,7 @@ export function TtsSection({ data }: Props) {
           to={ROUTES.TTS}
           className="inline-flex items-center gap-1.5 text-sm text-primary hover:underline"
         >
-          Manage TTS settings <ExternalLink className="h-3.5 w-3.5" />
+          {t("tts.manageLink")} <ExternalLink className="h-3.5 w-3.5" />
         </Link>
       </CardContent>
     </Card>
diff --git a/ui/web/src/pages/cron/cron-detail-page.tsx b/ui/web/src/pages/cron/cron-detail-page.tsx
index 2461536a..0f37765b 100644
--- a/ui/web/src/pages/cron/cron-detail-page.tsx
+++ b/ui/web/src/pages/cron/cron-detail-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { ArrowLeft, Play, Trash2, Power, Loader2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -38,6 +39,7 @@ interface CronDetailPageProps {
 }
 
 export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunLog, onRefresh }: CronDetailPageProps) {
+  const { t } = useTranslation("cron");
   const [confirmDelete, setConfirmDelete] = useState(false);
   const [confirmToggle, setConfirmToggle] = useState(false);
   const [runLog, setRunLog] = useState<CronRunLogEntry[]>([]);
@@ -93,7 +95,7 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
             <h3 className="flex items-center gap-2 font-medium">
               {job.name}
               <Badge variant={job.enabled ? "success" : "secondary"}>
-                {job.enabled ? "enabled" : "disabled"}
+                {job.enabled ? t("detail.enabled") : t("detail.disabled")}
               </Badge>
             </h3>
             <div className="mt-0.5 flex items-center gap-2 text-xs text-muted-foreground">
@@ -105,7 +107,7 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
                     : job.state.lastStatus === "running" ? "outline"
                     : "destructive"
                 }>
-                  {job.state.lastStatus === "running" ? "running..." : job.state.lastStatus}
+                  {job.state.lastStatus === "running" ? t("detail.runningStatus") : job.state.lastStatus}
                 </Badge>
               )}
             </div>
@@ -123,7 +125,7 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
             }}
           >
             {isRunning ? <Loader2 className="h-3.5 w-3.5 animate-spin" /> : <Play className="h-3.5 w-3.5" />}
-            {isRunning ? "Running..." : "Run Now"}
+            {isRunning ? t("detail.running") : t("detail.runNow")}
           </Button>
           <Button
             variant="outline"
@@ -131,10 +133,10 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
             className="gap-1"
             onClick={() => setConfirmToggle(true)}
           >
-            <Power className="h-3.5 w-3.5" /> {job.enabled ? "Disable" : "Enable"}
+            <Power className="h-3.5 w-3.5" /> {job.enabled ? t("detail.disable") : t("detail.enable")}
           </Button>
           <Button variant="destructive" size="sm" className="gap-1" onClick={() => setConfirmDelete(true)}>
-            <Trash2 className="h-3.5 w-3.5" /> Delete
+            <Trash2 className="h-3.5 w-3.5" /> {t("detail.delete")}
           </Button>
         </div>
       </div>
@@ -144,30 +146,30 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
         <div className="mx-auto max-w-3xl space-y-6">
           {/* Job Info */}
           <div className="grid grid-cols-2 gap-4 rounded-md border p-4 text-sm">
-            <InfoRow label="Schedule" value={formatScheduleDetail(job)} />
-            {job.schedule.tz && <InfoRow label="Timezone" value={job.schedule.tz} />}
+            <InfoRow label={t("detail.infoRows.schedule")} value={formatScheduleDetail(job)} />
+            {job.schedule.tz && <InfoRow label={t("detail.infoRows.timezone")} value={job.schedule.tz} />}
             {job.state?.nextRunAtMs && (
-              <InfoRow label="Next Run" value={formatDate(new Date(job.state.nextRunAtMs))} />
+              <InfoRow label={t("detail.infoRows.nextRun")} value={formatDate(new Date(job.state.nextRunAtMs))} />
             )}
             {job.state?.lastRunAtMs && (
-              <InfoRow label="Last Run" value={formatDate(new Date(job.state.lastRunAtMs))} />
+              <InfoRow label={t("detail.infoRows.lastRun")} value={formatDate(new Date(job.state.lastRunAtMs))} />
             )}
-            <InfoRow label="Created" value={formatDate(new Date(job.createdAtMs))} />
-            <InfoRow label="Updated" value={formatDate(new Date(job.updatedAtMs))} />
-            {job.deleteAfterRun && <InfoRow label="Auto-delete" value="Yes (one-time)" />}
+            <InfoRow label={t("detail.infoRows.created")} value={formatDate(new Date(job.createdAtMs))} />
+            <InfoRow label={t("detail.infoRows.updated")} value={formatDate(new Date(job.updatedAtMs))} />
+            {job.deleteAfterRun && <InfoRow label={t("detail.infoRows.autoDelete")} value={t("detail.infoRows.autoDeleteValue")} />}
           </div>
 
           {/* Payload */}
           <div className="rounded-md border p-4 text-sm">
-            <h4 className="mb-2 font-medium">Payload</h4>
+            <h4 className="mb-2 font-medium">{t("detail.payload")}</h4>
             <div className="space-y-2">
               <div className="rounded bg-muted p-3 font-mono text-xs whitespace-pre-wrap">
-                {job.payload?.message || "(empty)"}
+                {job.payload?.message || t("detail.empty")}
               </div>
               <div className="flex gap-4 text-xs text-muted-foreground">
-                {job.payload?.deliver && <span>Deliver: direct</span>}
-                {job.payload?.channel && <span>Channel: {job.payload.channel}</span>}
-                {job.payload?.to && <span>To: {job.payload.to}</span>}
+                {job.payload?.deliver && <span>{t("detail.deliverDirect")}</span>}
+                {job.payload?.channel && <span>{t("detail.channel", { name: job.payload.channel })}</span>}
+                {job.payload?.to && <span>{t("detail.to", { name: job.payload.to })}</span>}
               </div>
             </div>
           </div>
@@ -175,7 +177,7 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
           {/* Last Error */}
           {job.state?.lastError && (
             <div className="rounded-md border border-destructive/30 bg-destructive/5 p-4 text-sm">
-              <h4 className="mb-1 font-medium text-destructive">Last Error</h4>
+              <h4 className="mb-1 font-medium text-destructive">{t("detail.lastError")}</h4>
               <p className="text-xs text-destructive/80">{job.state.lastError}</p>
             </div>
           )}
@@ -183,9 +185,9 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
           {/* Run History */}
           <div>
             <div className="mb-3 flex items-center justify-between">
-              <h4 className="font-medium">Run History</h4>
+              <h4 className="font-medium">{t("detail.runHistory")}</h4>
               <Button variant="ghost" size="sm" onClick={() => loadRunLog()} className="text-xs">
-                Refresh
+                {t("detail.refresh")}
               </Button>
             </div>
             {runLogLoading && runLog.length === 0 ? (
@@ -193,7 +195,7 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
                 <div className="h-5 w-5 animate-spin rounded-full border-2 border-muted-foreground border-t-transparent" />
               </div>
             ) : runLog.length === 0 ? (
-              <p className="py-8 text-center text-sm text-muted-foreground">No run history yet.</p>
+              <p className="py-8 text-center text-sm text-muted-foreground">{t("detail.noHistory")}</p>
             ) : (
               <>
                 <div className="space-y-2">
@@ -209,7 +211,7 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
                         <div className="flex items-center gap-2">
                           {(entry.inputTokens != null && entry.inputTokens > 0) && (
                             <span className="text-xs text-muted-foreground">
-                              {formatTokens(entry.inputTokens)} in / {formatTokens(entry.outputTokens ?? 0)} out
+                              {t("detail.inOut", { input: formatTokens(entry.inputTokens), output: formatTokens(entry.outputTokens ?? 0) })}
                             </span>
                           )}
                           <Badge variant={entry.status === "ok" || entry.status === "success" ? "success" : "destructive"}>
@@ -244,9 +246,9 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
       <ConfirmDialog
         open={confirmDelete}
         onOpenChange={setConfirmDelete}
-        title="Delete Cron Job"
-        description={`Delete "${job.name}"? This cannot be undone.`}
-        confirmLabel="Delete"
+        title={t("delete.title")}
+        description={t("delete.description", { name: job.name })}
+        confirmLabel={t("delete.confirmLabel")}
         variant="destructive"
         onConfirm={async () => {
           await onDelete(job.id);
@@ -257,13 +259,13 @@ export function CronDetailPage({ job, onBack, onRun, onToggle, onDelete, getRunL
       <ConfirmDialog
         open={confirmToggle}
         onOpenChange={setConfirmToggle}
-        title={job.enabled ? "Disable Cron Job" : "Enable Cron Job"}
+        title={job.enabled ? t("disable.title") : t("enable.title")}
         description={
           job.enabled
-            ? `Disable "${job.name}"? It will stop running until re-enabled.`
-            : `Enable "${job.name}"? It will start running on schedule.`
+            ? t("disable.description", { name: job.name })
+            : t("enable.description", { name: job.name })
         }
-        confirmLabel={job.enabled ? "Disable" : "Enable"}
+        confirmLabel={job.enabled ? t("disable.confirmLabel") : t("enable.confirmLabel")}
         variant={job.enabled ? "destructive" : "default"}
         onConfirm={async () => {
           await onToggle(job.id, !job.enabled);
diff --git a/ui/web/src/pages/cron/cron-form-dialog.tsx b/ui/web/src/pages/cron/cron-form-dialog.tsx
index d28fdb07..40d8c92b 100644
--- a/ui/web/src/pages/cron/cron-form-dialog.tsx
+++ b/ui/web/src/pages/cron/cron-form-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -27,6 +28,7 @@ interface CronFormDialogProps {
 type ScheduleKind = "every" | "cron" | "at";
 
 export function CronFormDialog({ open, onOpenChange, onSubmit }: CronFormDialogProps) {
+  const { t } = useTranslation("cron");
   const [name, setName] = useState("");
   const [message, setMessage] = useState("");
   const [agentId, setAgentId] = useState("");
@@ -68,22 +70,22 @@ export function CronFormDialog({ open, onOpenChange, onSubmit }: CronFormDialogP
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-h-[85vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>Create Cron Job</DialogTitle>
+          <DialogTitle>{t("create.title")}</DialogTitle>
         </DialogHeader>
         <div className="space-y-4 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
           <div className="space-y-2">
-            <Label>Name</Label>
-            <Input value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder="my-daily-task" />
-            <p className="text-xs text-muted-foreground">Lowercase letters, numbers, and hyphens only</p>
+            <Label>{t("create.name")}</Label>
+            <Input value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder={t("create.namePlaceholder")} />
+            <p className="text-xs text-muted-foreground">{t("create.nameHint")}</p>
           </div>
 
           <div className="space-y-2">
-            <Label>Agent ID (optional)</Label>
-            <Input value={agentId} onChange={(e) => setAgentId(e.target.value)} placeholder="default" />
+            <Label>{t("create.agentId")}</Label>
+            <Input value={agentId} onChange={(e) => setAgentId(e.target.value)} placeholder={t("create.agentIdPlaceholder")} />
           </div>
 
           <div className="space-y-2">
-            <Label>Schedule Type</Label>
+            <Label>{t("create.scheduleType")}</Label>
             <div className="flex gap-2">
               {(["every", "cron", "at"] as const).map((kind) => (
                 <Button
@@ -92,7 +94,7 @@ export function CronFormDialog({ open, onOpenChange, onSubmit }: CronFormDialogP
                   size="sm"
                   onClick={() => setScheduleKind(kind)}
                 >
-                  {kind === "every" ? "Every" : kind === "cron" ? "Cron" : "Once"}
+                  {kind === "every" ? t("create.every") : kind === "cron" ? t("create.cron") : t("create.once")}
                 </Button>
               ))}
             </div>
@@ -100,7 +102,7 @@ export function CronFormDialog({ open, onOpenChange, onSubmit }: CronFormDialogP
 
           {scheduleKind === "every" && (
             <div className="space-y-2">
-              <Label>Interval (seconds)</Label>
+              <Label>{t("create.intervalSeconds")}</Label>
               <Input
                 type="number"
                 min={1}
@@ -113,38 +115,38 @@ export function CronFormDialog({ open, onOpenChange, onSubmit }: CronFormDialogP
 
           {scheduleKind === "cron" && (
             <div className="space-y-2">
-              <Label>Cron Expression</Label>
+              <Label>{t("create.cronExpression")}</Label>
               <Input
                 value={cronExpr}
                 onChange={(e) => setCronExpr(e.target.value)}
                 placeholder="0 * * * *"
               />
-              <p className="text-xs text-muted-foreground">Standard 5-field cron: min hour day month weekday</p>
+              <p className="text-xs text-muted-foreground">{t("create.cronHint")}</p>
             </div>
           )}
 
           {scheduleKind === "at" && (
             <p className="text-sm text-muted-foreground">
-              The job will run once, approximately 1 minute from now.
+              {t("create.onceDesc")}
             </p>
           )}
 
           <div className="space-y-2">
-            <Label>Message</Label>
+            <Label>{t("create.message")}</Label>
             <Textarea
               value={message}
               onChange={(e) => setMessage(e.target.value)}
-              placeholder="What should the agent do?"
+              placeholder={t("create.messagePlaceholder")}
               rows={3}
             />
           </div>
         </div>
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={saving}>
-            Cancel
+            {t("create.cancel")}
           </Button>
           <Button onClick={handleSubmit} disabled={saving || !name.trim() || !isValidSlug(name.trim()) || !message.trim()}>
-            {saving ? "Creating..." : "Create"}
+            {saving ? t("create.creating") : t("create.create")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/cron/cron-page.tsx b/ui/web/src/pages/cron/cron-page.tsx
index fb763005..aeb1a0c6 100644
--- a/ui/web/src/pages/cron/cron-page.tsx
+++ b/ui/web/src/pages/cron/cron-page.tsx
@@ -1,5 +1,6 @@
 import { useState } from "react";
 import { useParams, useNavigate } from "react-router";
+import { useTranslation } from "react-i18next";
 import { Clock, Plus, Play, Trash2, History, RefreshCw, Loader2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -31,6 +32,8 @@ function formatSchedule(job: CronJob): string {
 }
 
 export function CronPage() {
+  const { t } = useTranslation("cron");
+  const { t: tc } = useTranslation("common");
   const { id: detailId } = useParams<{ id: string }>();
   const navigate = useNavigate();
   const { jobs, loading, refreshing, refresh, createJob, toggleJob, deleteJob, runJob, getRunLog } = useCron();
@@ -77,15 +80,15 @@ export function CronPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Cron"
-        description="Schedule recurring agent tasks"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex gap-2">
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
             </Button>
             <Button size="sm" onClick={() => setShowCreate(true)} className="gap-1">
-              <Plus className="h-3.5 w-3.5" /> New Job
+              <Plus className="h-3.5 w-3.5" /> {t("newJob")}
             </Button>
           </div>
         }
@@ -97,11 +100,11 @@ export function CronPage() {
         ) : jobs.length === 0 ? (
           <EmptyState
             icon={Clock}
-            title="No cron jobs"
-            description="Create a cron job to schedule recurring agent tasks."
+            title={t("emptyTitle")}
+            description={t("emptyDescription")}
             action={
               <Button size="sm" onClick={() => setShowCreate(true)} className="gap-1">
-                <Plus className="h-3.5 w-3.5" /> New Job
+                <Plus className="h-3.5 w-3.5" /> {t("newJob")}
               </Button>
             }
           />
@@ -110,12 +113,12 @@ export function CronPage() {
             <table className="w-full min-w-[700px] text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Enabled</th>
-                  <th className="px-4 py-3 text-left font-medium">Name</th>
-                  <th className="px-4 py-3 text-left font-medium">Schedule</th>
-                  <th className="px-4 py-3 text-left font-medium">Message</th>
-                  <th className="px-4 py-3 text-left font-medium">Agent</th>
-                  <th className="px-4 py-3 text-right font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.enabled")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.name")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.schedule")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.message")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.agent")}</th>
+                  <th className="px-4 py-3 text-right font-medium">{t("columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -146,7 +149,7 @@ export function CronPage() {
                       {job.agentId ? (
                         <Badge variant="secondary">{job.agentId}</Badge>
                       ) : (
-                        <span className="text-muted-foreground">default</span>
+                        <span className="text-muted-foreground">{t("defaultAgent")}</span>
                       )}
                     </td>
                     <td className="px-4 py-3">
@@ -154,7 +157,7 @@ export function CronPage() {
                         <Button
                           variant="ghost"
                           size="icon"
-                          title={job.state?.lastStatus === "running" ? "Running..." : "Run now"}
+                          title={job.state?.lastStatus === "running" ? t("running") : t("runNow")}
                           disabled={job.state?.lastStatus === "running"}
                           onClick={() => runJob(job.id)}
                         >
@@ -165,7 +168,7 @@ export function CronPage() {
                         <Button
                           variant="ghost"
                           size="icon"
-                          title="Run history"
+                          title={t("runHistory")}
                           onClick={() => handleShowRunLog(job)}
                         >
                           <History className="h-3.5 w-3.5" />
@@ -173,7 +176,7 @@ export function CronPage() {
                         <Button
                           variant="ghost"
                           size="icon"
-                          title="Delete"
+                          title={t("delete.confirmLabel")}
                           onClick={() => setDeleteTarget(job)}
                         >
                           <Trash2 className="h-3.5 w-3.5" />
@@ -206,13 +209,13 @@ export function CronPage() {
         <ConfirmDialog
           open
           onOpenChange={() => setToggleTarget(null)}
-          title={toggleTarget.enabled ? "Enable Cron Job" : "Disable Cron Job"}
+          title={toggleTarget.enabled ? t("enable.title") : t("disable.title")}
           description={
             toggleTarget.enabled
-              ? `Enable "${toggleTarget.job.name}"? It will start running on schedule.`
-              : `Disable "${toggleTarget.job.name}"? It will stop running until re-enabled.`
+              ? t("enable.description", { name: toggleTarget.job.name })
+              : t("disable.description", { name: toggleTarget.job.name })
           }
-          confirmLabel={toggleTarget.enabled ? "Enable" : "Disable"}
+          confirmLabel={toggleTarget.enabled ? t("enable.confirmLabel") : t("disable.confirmLabel")}
           variant={toggleTarget.enabled ? "default" : "destructive"}
           onConfirm={async () => {
             await toggleJob(toggleTarget.job.id, toggleTarget.enabled);
@@ -225,9 +228,9 @@ export function CronPage() {
         <ConfirmDialog
           open
           onOpenChange={() => setDeleteTarget(null)}
-          title="Delete Cron Job"
-          description={`Delete "${deleteTarget.name}"? This cannot be undone.`}
-          confirmLabel="Delete"
+          title={t("delete.title")}
+          description={t("delete.description", { name: deleteTarget.name })}
+          confirmLabel={t("delete.confirmLabel")}
           variant="destructive"
           onConfirm={async () => {
             await deleteJob(deleteTarget.id);
diff --git a/ui/web/src/pages/cron/cron-run-log-dialog.tsx b/ui/web/src/pages/cron/cron-run-log-dialog.tsx
index d3359370..1a54d21e 100644
--- a/ui/web/src/pages/cron/cron-run-log-dialog.tsx
+++ b/ui/web/src/pages/cron/cron-run-log-dialog.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -23,11 +24,13 @@ export function CronRunLogDialog({
   entries,
   loading,
 }: CronRunLogDialogProps) {
+  const { t } = useTranslation("cron");
+
   return (
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-h-[70vh] overflow-y-auto sm:max-w-2xl">
         <DialogHeader>
-          <DialogTitle>Run Log: {jobName}</DialogTitle>
+          <DialogTitle>{t("runLog.title", { name: jobName })}</DialogTitle>
         </DialogHeader>
 
         {loading && entries.length === 0 ? (
@@ -36,7 +39,7 @@ export function CronRunLogDialog({
           </div>
         ) : entries.length === 0 ? (
           <p className="py-8 text-center text-sm text-muted-foreground">
-            No run history yet.
+            {t("runLog.noHistory")}
           </p>
         ) : (
           <div className="space-y-2">
diff --git a/ui/web/src/pages/cron/hooks/use-cron.ts b/ui/web/src/pages/cron/hooks/use-cron.ts
index d0f9c036..677d2146 100644
--- a/ui/web/src/pages/cron/hooks/use-cron.ts
+++ b/ui/web/src/pages/cron/hooks/use-cron.ts
@@ -1,5 +1,6 @@
 import { useCallback } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
+import i18next from "i18next";
 import { useWs } from "@/hooks/use-ws";
 import { useAuthStore } from "@/stores/use-auth-store";
 import { Methods } from "@/api/protocol";
@@ -85,9 +86,9 @@ export function useCron() {
       try {
         await ws.call(Methods.CRON_CREATE, params);
         await invalidate();
-        toast.success("Cron job created", `${params.name} has been added`);
+        toast.success(i18next.t("cron:toast.created"), i18next.t("cron:toast.createdDesc", { name: params.name }));
       } catch (err) {
-        toast.error("Failed to create cron job", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("cron:toast.failedCreate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -99,9 +100,9 @@ export function useCron() {
       try {
         await ws.call(Methods.CRON_TOGGLE, { jobId, enabled });
         await invalidate();
-        toast.success(enabled ? "Cron job enabled" : "Cron job disabled");
+        toast.success(enabled ? i18next.t("cron:toast.enabled") : i18next.t("cron:toast.disabled"));
       } catch (err) {
-        toast.error("Failed to toggle cron job", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("cron:toast.failedToggle"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -113,9 +114,9 @@ export function useCron() {
       try {
         await ws.call(Methods.CRON_DELETE, { jobId });
         await invalidate();
-        toast.success("Cron job deleted");
+        toast.success(i18next.t("cron:toast.deleted"));
       } catch (err) {
-        toast.error("Failed to delete cron job", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("cron:toast.failedDelete"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -126,9 +127,9 @@ export function useCron() {
     async (jobId: string) => {
       try {
         await ws.call(Methods.CRON_RUN, { jobId, mode: "force" });
-        toast.success("Cron job triggered");
+        toast.success(i18next.t("cron:toast.triggered"));
       } catch (err) {
-        toast.error("Failed to run cron job", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("cron:toast.failedRun"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
diff --git a/ui/web/src/pages/custom-tools/custom-tool-form-dialog.tsx b/ui/web/src/pages/custom-tools/custom-tool-form-dialog.tsx
index 28fee1fa..de5cd8f5 100644
--- a/ui/web/src/pages/custom-tools/custom-tool-form-dialog.tsx
+++ b/ui/web/src/pages/custom-tools/custom-tool-form-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -22,6 +23,7 @@ interface CustomToolFormDialogProps {
 }
 
 export function CustomToolFormDialog({ open, onOpenChange, tool, onSubmit }: CustomToolFormDialogProps) {
+  const { t } = useTranslation("tools");
   const [name, setName] = useState("");
   const [description, setDescription] = useState("");
   const [command, setCommand] = useState("");
@@ -49,11 +51,11 @@ export function CustomToolFormDialog({ open, onOpenChange, tool, onSubmit }: Cus
 
   const handleSubmit = async () => {
     if (!name.trim() || !command.trim()) {
-      setError("Name and command are required");
+      setError(t("custom.form.errors.nameRequired"));
       return;
     }
     if (!isValidSlug(name.trim())) {
-      setError("Name must be a valid slug (lowercase letters, numbers, hyphens only)");
+      setError(t("custom.form.errors.nameSlug"));
       return;
     }
 
@@ -62,7 +64,7 @@ export function CustomToolFormDialog({ open, onOpenChange, tool, onSubmit }: Cus
       try {
         parsedParams = JSON.parse(parameters);
       } catch {
-        setError("Parameters must be valid JSON");
+        setError(t("custom.form.errors.invalidJson"));
         return;
       }
     }
@@ -82,7 +84,7 @@ export function CustomToolFormDialog({ open, onOpenChange, tool, onSubmit }: Cus
       });
       onOpenChange(false);
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Failed to save");
+      setError(err instanceof Error ? err.message : t("custom.form.saving"));
     } finally {
       setLoading(false);
     }
@@ -92,23 +94,23 @@ export function CustomToolFormDialog({ open, onOpenChange, tool, onSubmit }: Cus
     <Dialog open={open} onOpenChange={(v) => !loading && onOpenChange(v)}>
       <DialogContent className="max-h-[85vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>{tool ? "Edit Tool" : "Create Custom Tool"}</DialogTitle>
+          <DialogTitle>{tool ? t("custom.form.editTitle") : t("custom.form.createTitle")}</DialogTitle>
         </DialogHeader>
 
         <div className="grid gap-4 py-2 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
           <div className="grid gap-1.5">
-            <Label htmlFor="ct-name">Name *</Label>
-            <Input id="ct-name" value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder="my-tool" />
-            <p className="text-xs text-muted-foreground">Lowercase letters, numbers, and hyphens only</p>
+            <Label htmlFor="ct-name">{t("custom.form.name")}</Label>
+            <Input id="ct-name" value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder={t("custom.form.namePlaceholder")} />
+            <p className="text-xs text-muted-foreground">{t("custom.form.nameHint")}</p>
           </div>
 
           <div className="grid gap-1.5">
-            <Label htmlFor="ct-desc">Description</Label>
-            <Textarea id="ct-desc" value={description} onChange={(e) => setDescription(e.target.value)} placeholder="What this tool does..." rows={2} />
+            <Label htmlFor="ct-desc">{t("custom.form.description")}</Label>
+            <Textarea id="ct-desc" value={description} onChange={(e) => setDescription(e.target.value)} placeholder={t("custom.form.descriptionPlaceholder")} rows={2} />
           </div>
 
           <div className="grid gap-1.5">
-            <Label htmlFor="ct-cmd">Command *</Label>
+            <Label htmlFor="ct-cmd">{t("custom.form.command")}</Label>
             <Textarea
               id="ct-cmd"
               value={command}
@@ -117,11 +119,11 @@ export function CustomToolFormDialog({ open, onOpenChange, tool, onSubmit }: Cus
               className="font-mono text-sm"
               rows={3}
             />
-            <p className="text-xs text-muted-foreground">Shell template. Use {"{{.key}}"} for parameter placeholders.</p>
+            <p className="text-xs text-muted-foreground">{t("custom.form.commandHint")}</p>
           </div>
 
           <div className="grid gap-1.5">
-            <Label htmlFor="ct-params">Parameters (JSON Schema)</Label>
+            <Label htmlFor="ct-params">{t("custom.form.parameters")}</Label>
             <Textarea
               id="ct-params"
               value={parameters}
@@ -134,31 +136,31 @@ export function CustomToolFormDialog({ open, onOpenChange, tool, onSubmit }: Cus
 
           <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
             <div className="grid gap-1.5">
-              <Label htmlFor="ct-wd">Working Directory</Label>
-              <Input id="ct-wd" value={workingDir} onChange={(e) => setWorkingDir(e.target.value)} placeholder="/path/to/dir" />
+              <Label htmlFor="ct-wd">{t("custom.form.workingDir")}</Label>
+              <Input id="ct-wd" value={workingDir} onChange={(e) => setWorkingDir(e.target.value)} placeholder={t("custom.form.workingDirPlaceholder")} />
             </div>
             <div className="grid gap-1.5">
-              <Label htmlFor="ct-timeout">Timeout (seconds)</Label>
+              <Label htmlFor="ct-timeout">{t("custom.form.timeout")}</Label>
               <Input id="ct-timeout" type="number" value={timeout} onChange={(e) => setTimeout(Number(e.target.value))} min={1} />
             </div>
           </div>
 
           <div className="grid gap-1.5">
-            <Label htmlFor="ct-agent">Agent ID (optional)</Label>
-            <Input id="ct-agent" value={agentId} onChange={(e) => setAgentId(e.target.value)} placeholder="Leave blank for global scope" />
+            <Label htmlFor="ct-agent">{t("custom.form.agentId")}</Label>
+            <Input id="ct-agent" value={agentId} onChange={(e) => setAgentId(e.target.value)} placeholder={t("custom.form.agentIdPlaceholder")} />
           </div>
 
           <div className="flex items-center gap-2">
             <Switch id="ct-enabled" checked={enabled} onCheckedChange={setEnabled} />
-            <Label htmlFor="ct-enabled">Enabled</Label>
+            <Label htmlFor="ct-enabled">{t("custom.form.enabled")}</Label>
           </div>
           {error && <p className="text-sm text-destructive">{error}</p>}
         </div>
 
         <DialogFooter>
-          <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>Cancel</Button>
+          <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>{t("custom.form.cancel")}</Button>
           <Button onClick={handleSubmit} disabled={loading}>
-            {loading ? "Saving..." : tool ? "Update" : "Create"}
+            {loading ? t("custom.form.saving") : tool ? t("custom.form.update") : t("custom.form.create")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/custom-tools/custom-tools-page.tsx b/ui/web/src/pages/custom-tools/custom-tools-page.tsx
index 5477a82e..995ca809 100644
--- a/ui/web/src/pages/custom-tools/custom-tools-page.tsx
+++ b/ui/web/src/pages/custom-tools/custom-tools-page.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Wrench, Plus, RefreshCw, Pencil, Trash2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -16,6 +17,8 @@ import { useRef } from "react";
 import { useDebouncedCallback } from "@/hooks/use-debounced-callback";
 
 export function CustomToolsPage() {
+  const { t } = useTranslation("tools");
+  const { t: tc } = useTranslation("common");
   const [search, setSearch] = useState("");
   const [debouncedSearch, setDebouncedSearch] = useState("");
   const [page, setPage] = useState(1);
@@ -69,15 +72,15 @@ export function CustomToolsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Custom Tools"
-        description="Manage custom shell-based tools for agents"
+        title={t("custom.title")}
+        description={t("custom.description")}
         actions={
           <div className="flex gap-2">
             <Button size="sm" onClick={() => { setEditTool(null); setFormOpen(true); }} className="gap-1">
-              <Plus className="h-3.5 w-3.5" /> Create Tool
+              <Plus className="h-3.5 w-3.5" /> {t("custom.createTool")}
             </Button>
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
             </Button>
           </div>
         }
@@ -87,7 +90,7 @@ export function CustomToolsPage() {
         <SearchInput
           value={search}
           onChange={handleSearchChange}
-          placeholder="Search tools..."
+          placeholder={t("custom.searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -98,20 +101,20 @@ export function CustomToolsPage() {
         ) : tools.length === 0 ? (
           <EmptyState
             icon={Wrench}
-            title={debouncedSearch ? "No matching tools" : "No custom tools"}
-            description={debouncedSearch ? "Try a different search term." : "Create your first custom tool to get started."}
+            title={debouncedSearch ? t("custom.noMatchTitle") : t("custom.emptyTitle")}
+            description={debouncedSearch ? t("custom.noMatchDescription") : t("custom.emptyDescription")}
           />
         ) : (
           <div className="rounded-md border">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Name</th>
-                  <th className="px-4 py-3 text-left font-medium">Description</th>
-                  <th className="px-4 py-3 text-left font-medium">Scope</th>
-                  <th className="px-4 py-3 text-left font-medium">Enabled</th>
-                  <th className="px-4 py-3 text-left font-medium">Timeout</th>
-                  <th className="px-4 py-3 text-right font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("custom.columns.name")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("custom.columns.description")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("custom.columns.scope")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("custom.columns.enabled")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("custom.columns.timeout")}</th>
+                  <th className="px-4 py-3 text-right font-medium">{t("custom.columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -124,16 +127,16 @@ export function CustomToolsPage() {
                       </div>
                     </td>
                     <td className="px-4 py-3 text-muted-foreground">
-                      {tool.description || "No description"}
+                      {tool.description || t("custom.noDescription")}
                     </td>
                     <td className="px-4 py-3">
                       <Badge variant={tool.agent_id ? "secondary" : "outline"}>
-                        {tool.agent_id ? "Agent" : "Global"}
+                        {tool.agent_id ? t("custom.scope.agent") : t("custom.scope.global")}
                       </Badge>
                     </td>
                     <td className="px-4 py-3">
                       <Badge variant={tool.enabled ? "default" : "secondary"}>
-                        {tool.enabled ? "Yes" : "No"}
+                        {tool.enabled ? tc("yes") : tc("no")}
                       </Badge>
                     </td>
                     <td className="px-4 py-3 text-muted-foreground">{tool.timeout_seconds}s</td>
@@ -145,7 +148,7 @@ export function CustomToolsPage() {
                           onClick={() => { setEditTool(tool); setFormOpen(true); }}
                           className="gap-1"
                         >
-                          <Pencil className="h-3.5 w-3.5" /> Edit
+                          <Pencil className="h-3.5 w-3.5" /> {tc("edit")}
                         </Button>
                         <Button
                           variant="ghost"
@@ -183,9 +186,9 @@ export function CustomToolsPage() {
       <ConfirmDialog
         open={!!deleteTarget}
         onOpenChange={(open) => !open && setDeleteTarget(null)}
-        title="Delete Custom Tool"
-        description={`Are you sure you want to delete "${deleteTarget?.name}"? This action cannot be undone.`}
-        confirmLabel="Delete"
+        title={t("custom.delete.title")}
+        description={t("custom.delete.description", { name: deleteTarget?.name })}
+        confirmLabel={t("custom.delete.confirmLabel")}
         variant="destructive"
         onConfirm={handleDelete}
         loading={deleteLoading}
diff --git a/ui/web/src/pages/custom-tools/hooks/use-custom-tools.ts b/ui/web/src/pages/custom-tools/hooks/use-custom-tools.ts
index 9b2e9053..8466a68e 100644
--- a/ui/web/src/pages/custom-tools/hooks/use-custom-tools.ts
+++ b/ui/web/src/pages/custom-tools/hooks/use-custom-tools.ts
@@ -1,5 +1,6 @@
 import { useCallback } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
+import i18next from "i18next";
 import { useHttp } from "@/hooks/use-ws";
 import { queryKeys } from "@/lib/query-keys";
 import { toast } from "@/stores/use-toast-store";
@@ -46,10 +47,10 @@ export function useCustomTools(filters: CustomToolFilters = {}) {
       try {
         const res = await http.post<{ id: string }>("/v1/tools/custom", data);
         await invalidate();
-        toast.success("Custom tool created", `${data.name} has been added`);
+        toast.success(i18next.t("tools:custom.toast.created"), i18next.t("tools:custom.toast.createdDesc", { name: data.name }));
         return res;
       } catch (err) {
-        toast.error("Failed to create custom tool", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("tools:custom.toast.failedCreate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -61,9 +62,9 @@ export function useCustomTools(filters: CustomToolFilters = {}) {
       try {
         await http.put(`/v1/tools/custom/${id}`, data);
         await invalidate();
-        toast.success("Custom tool updated");
+        toast.success(i18next.t("tools:custom.toast.updated"));
       } catch (err) {
-        toast.error("Failed to update custom tool", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("tools:custom.toast.failedUpdate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -75,9 +76,9 @@ export function useCustomTools(filters: CustomToolFilters = {}) {
       try {
         await http.delete(`/v1/tools/custom/${id}`);
         await invalidate();
-        toast.success("Custom tool deleted");
+        toast.success(i18next.t("tools:custom.toast.deleted"));
       } catch (err) {
-        toast.error("Failed to delete custom tool", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("tools:custom.toast.failedDelete"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
diff --git a/ui/web/src/pages/delegations/delegation-detail-dialog.tsx b/ui/web/src/pages/delegations/delegation-detail-dialog.tsx
index 26753bf1..d688ab42 100644
--- a/ui/web/src/pages/delegations/delegation-detail-dialog.tsx
+++ b/ui/web/src/pages/delegations/delegation-detail-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -19,6 +20,7 @@ interface DelegationDetailDialogProps {
 }
 
 export function DelegationDetailDialog({ delegationId, onClose, getDelegation, getTrace }: DelegationDetailDialogProps) {
+  const { t } = useTranslation("delegations");
   const [record, setRecord] = useState<DelegationHistoryRecord | null>(null);
   const [loading, setLoading] = useState(true);
   const [viewingTraceId, setViewingTraceId] = useState<string | null>(null);
@@ -43,7 +45,7 @@ export function DelegationDetailDialog({ delegationId, onClose, getDelegation, g
     <Dialog open onOpenChange={() => onClose()}>
       <DialogContent className="max-h-[85vh] overflow-y-auto sm:max-w-4xl">
         <DialogHeader>
-          <DialogTitle>Delegation Detail</DialogTitle>
+          <DialogTitle>{t("detail.title")}</DialogTitle>
         </DialogHeader>
 
         {loading && !record ? (
@@ -51,48 +53,48 @@ export function DelegationDetailDialog({ delegationId, onClose, getDelegation, g
             <div className="h-6 w-6 animate-spin rounded-full border-2 border-muted-foreground border-t-transparent" />
           </div>
         ) : !record ? (
-          <p className="py-8 text-center text-sm text-muted-foreground">Delegation not found.</p>
+          <p className="py-8 text-center text-sm text-muted-foreground">{t("detail.notFound")}</p>
         ) : (
           <div className="space-y-4">
             {/* Summary grid */}
             <div className="grid grid-cols-2 gap-3 text-sm sm:grid-cols-4">
               <div>
-                <span className="text-muted-foreground">Source:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.source")}</span>{" "}
                 <span className="font-medium">{record.source_agent_key || record.source_agent_id.slice(0, 8)}</span>
               </div>
               <div>
-                <span className="text-muted-foreground">Target:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.target")}</span>{" "}
                 <span className="font-medium">{record.target_agent_key || record.target_agent_id.slice(0, 8)}</span>
               </div>
               <div>
-                <span className="text-muted-foreground">Status:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.status")}</span>{" "}
                 <Badge variant={statusVariant} className="text-xs">{record.status}</Badge>
               </div>
               <div>
-                <span className="text-muted-foreground">Mode:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.mode")}</span>{" "}
                 <Badge variant="outline" className="text-xs">{record.mode}</Badge>
               </div>
               <div>
-                <span className="text-muted-foreground">Duration:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.duration")}</span>{" "}
                 {formatDuration(record.duration_ms)}
               </div>
               <div>
-                <span className="text-muted-foreground">Iterations:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.iterations")}</span>{" "}
                 {record.iterations}
               </div>
               <div>
-                <span className="text-muted-foreground">Created:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.created")}</span>{" "}
                 {formatDate(record.created_at)}
               </div>
               <div>
-                <span className="text-muted-foreground">Completed:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.completed")}</span>{" "}
                 {record.completed_at ? formatDate(record.completed_at) : "—"}
               </div>
             </div>
 
             {record.trace_id && (
               <div className="text-sm">
-                <span className="text-muted-foreground">Trace:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.trace")}</span>{" "}
                 <button
                   type="button"
                   onClick={() => setViewingTraceId(record.trace_id!)}
@@ -105,14 +107,14 @@ export function DelegationDetailDialog({ delegationId, onClose, getDelegation, g
 
             {/* Task */}
             <div className="rounded-md border p-3">
-              <p className="mb-1 text-xs font-medium text-muted-foreground">Task</p>
+              <p className="mb-1 text-xs font-medium text-muted-foreground">{t("detail.task")}</p>
               <pre className="whitespace-pre-wrap break-words text-sm">{record.task}</pre>
             </div>
 
             {/* Result */}
             {record.result && (
               <div className="rounded-md border p-3">
-                <p className="mb-1 text-xs font-medium text-muted-foreground">Result</p>
+                <p className="mb-1 text-xs font-medium text-muted-foreground">{t("detail.result")}</p>
                 <pre className="max-h-[50vh] overflow-y-auto whitespace-pre-wrap break-words text-sm">
                   {record.result}
                 </pre>
@@ -122,7 +124,7 @@ export function DelegationDetailDialog({ delegationId, onClose, getDelegation, g
             {/* Error */}
             {record.error && (
               <div className="rounded-md border border-red-400/30 bg-red-500/10 p-3">
-                <p className="mb-1 text-xs font-medium text-muted-foreground">Error</p>
+                <p className="mb-1 text-xs font-medium text-muted-foreground">{t("detail.error")}</p>
                 <p className="break-all text-sm text-red-300">{record.error}</p>
               </div>
             )}
diff --git a/ui/web/src/pages/delegations/delegations-page.tsx b/ui/web/src/pages/delegations/delegations-page.tsx
index ea78a15a..b5554283 100644
--- a/ui/web/src/pages/delegations/delegations-page.tsx
+++ b/ui/web/src/pages/delegations/delegations-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useRef, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { ArrowRightLeft, RefreshCw, Search } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -27,6 +28,8 @@ import type { AgentEventPayload } from "@/types/chat";
 import type { DelegationHistoryRecord } from "@/types/delegation";
 
 export function DelegationsPage() {
+  const { t } = useTranslation("delegations");
+  const { t: tc } = useTranslation("common");
   const { delegations, total, loading, load, getDelegation } = useDelegations();
   const { getTrace } = useTraces();
   const spinning = useMinLoading(loading);
@@ -89,11 +92,11 @@ export function DelegationsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Delegations"
-        description="Agent delegation history and results"
+        title={t("title")}
+        description={t("description")}
         actions={
           <Button variant="outline" size="sm" onClick={handleRefresh} disabled={spinning} className="gap-1">
-            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
           </Button>
         }
       />
@@ -104,7 +107,7 @@ export function DelegationsPage() {
           <Input
             value={sourceFilter}
             onChange={(e) => setSourceFilter(e.target.value)}
-            placeholder="Source agent..."
+            placeholder={t("sourceFilterPlaceholder")}
             className="pl-9"
           />
         </div>
@@ -113,7 +116,7 @@ export function DelegationsPage() {
           <Input
             value={targetFilter}
             onChange={(e) => setTargetFilter(e.target.value)}
-            placeholder="Target agent..."
+            placeholder={t("targetFilterPlaceholder")}
             className="pl-9"
           />
         </div>
@@ -122,16 +125,16 @@ export function DelegationsPage() {
             <SelectValue placeholder="Status" />
           </SelectTrigger>
           <SelectContent>
-            <SelectItem value="all">All</SelectItem>
-            <SelectItem value="pending">Pending</SelectItem>
-            <SelectItem value="running">Running</SelectItem>
-            <SelectItem value="completed">Completed</SelectItem>
-            <SelectItem value="failed">Failed</SelectItem>
-            <SelectItem value="cancelled">Cancelled</SelectItem>
+            <SelectItem value="all">{t("statusFilter.all")}</SelectItem>
+            <SelectItem value="pending">{t("statusFilter.pending")}</SelectItem>
+            <SelectItem value="running">{t("statusFilter.running")}</SelectItem>
+            <SelectItem value="completed">{t("statusFilter.completed")}</SelectItem>
+            <SelectItem value="failed">{t("statusFilter.failed")}</SelectItem>
+            <SelectItem value="cancelled">{t("statusFilter.cancelled")}</SelectItem>
           </SelectContent>
         </Select>
         <Button type="submit" variant="outline" size="sm">
-          Filter
+          {t("filter")}
         </Button>
       </form>
 
@@ -141,20 +144,20 @@ export function DelegationsPage() {
         ) : delegations.length === 0 ? (
           <EmptyState
             icon={ArrowRightLeft}
-            title="No delegations"
-            description="No delegation records found. Delegations are recorded when agents delegate tasks to other agents."
+            title={t("emptyTitle")}
+            description={t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Source / Target</th>
-                  <th className="px-4 py-3 text-left font-medium">Task</th>
-                  <th className="px-4 py-3 text-left font-medium">Status</th>
-                  <th className="px-4 py-3 text-left font-medium">Mode</th>
-                  <th className="px-4 py-3 text-left font-medium">Duration</th>
-                  <th className="px-4 py-3 text-left font-medium">Time</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.sourceTarget")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.task")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.status")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.mode")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.duration")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.time")}</th>
                 </tr>
               </thead>
               <tbody>
diff --git a/ui/web/src/pages/events/event-sections/event-detail-dialog.tsx b/ui/web/src/pages/events/event-sections/event-detail-dialog.tsx
index 2e66bbe4..09972be8 100644
--- a/ui/web/src/pages/events/event-sections/event-detail-dialog.tsx
+++ b/ui/web/src/pages/events/event-sections/event-detail-dialog.tsx
@@ -8,6 +8,7 @@ import {
   DialogFooter,
 } from "@/components/ui/dialog";
 import { Badge } from "@/components/ui/badge";
+import { useTranslation } from "react-i18next";
 import { useClipboard } from "@/hooks/use-clipboard";
 import type { TeamEventEntry } from "@/stores/use-team-event-store";
 
@@ -17,6 +18,7 @@ interface EventDetailDialogProps {
 }
 
 export function EventDetailDialog({ entry, onClose }: EventDetailDialogProps) {
+  const { t } = useTranslation("events");
   const json = JSON.stringify(entry.payload, null, 2);
   const { copied, copy } = useClipboard();
 
@@ -46,7 +48,7 @@ export function EventDetailDialog({ entry, onClose }: EventDetailDialogProps) {
             ) : (
               <Copy className="h-3 w-3" />
             )}
-            {copied ? "Copied" : "Copy"}
+            {copied ? t("detail.copied") : t("detail.copy")}
           </Button>
           <pre className="max-h-[60vh] overflow-auto whitespace-pre-wrap break-words rounded-md bg-muted p-4 text-sm leading-relaxed">
             <code>
diff --git a/ui/web/src/pages/events/events-page.tsx b/ui/web/src/pages/events/events-page.tsx
index 8dc4b67c..c6c75537 100644
--- a/ui/web/src/pages/events/events-page.tsx
+++ b/ui/web/src/pages/events/events-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useRef, useEffect, useMemo, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Radar, Trash2, Pause, Play, ArrowDown } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -10,17 +11,20 @@ import { Methods } from "@/api/protocol";
 import { EventCard } from "./event-sections";
 import type { TeamData } from "@/types/team";
 
-const EVENT_CATEGORIES = [
-  { label: "All", value: "all" },
-  { label: "Delegation", value: "delegation" },
-  { label: "Task", value: "team.task" },
-  { label: "Message", value: "team.message" },
-  { label: "Agent", value: "agent" },
-  { label: "Team CRUD", value: "team.crud" },
-  { label: "Agent Link", value: "agent_link" },
-] as const;
+const EVENT_CATEGORY_VALUES = ["all", "delegation", "team.task", "team.message", "agent", "team.crud", "agent_link"] as const;
+
+const CATEGORY_KEY_MAP: Record<string, string> = {
+  "all": "categories.all",
+  "delegation": "categories.delegation",
+  "team.task": "categories.task",
+  "team.message": "categories.message",
+  "agent": "categories.agent",
+  "team.crud": "categories.teamCrud",
+  "agent_link": "categories.agentLink",
+};
 
 export function EventsPage() {
+  const { t } = useTranslation("events");
   const allEvents = useTeamEventStore((s) => s.events);
   const paused = useTeamEventStore((s) => s.paused);
   const setPaused = useTeamEventStore((s) => s.setPaused);
@@ -52,7 +56,7 @@ export function EventsPage() {
 
   const resolveTeam = useCallback(
     (teamId: string | null): string => {
-      if (!teamId) return "Global";
+      if (!teamId) return t("global");
       return teamMap.get(teamId) ?? teamId.slice(0, 8);
     },
     [teamMap],
@@ -141,15 +145,15 @@ export function EventsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Realtime Events"
-        description="Live WebSocket events across all teams and agents"
+        title={t("title")}
+        description={t("description")}
         actions={
           <>
             <Badge variant={paused ? "warning" : "success"} className="text-xs">
-              {paused ? "Paused" : "Live"}
+              {paused ? t("paused") : t("live")}
             </Badge>
             <span className="text-xs text-muted-foreground">
-              {filteredEvents.length} event{filteredEvents.length !== 1 ? "s" : ""}
+              {filteredEvents.length !== 1 ? t("eventCountPlural", { count: filteredEvents.length }) : t("eventCount", { count: filteredEvents.length })}
             </span>
             <Button
               variant="outline"
@@ -158,7 +162,7 @@ export function EventsPage() {
               className="h-8 gap-1.5"
             >
               {paused ? <Play className="h-3.5 w-3.5" /> : <Pause className="h-3.5 w-3.5" />}
-              {paused ? "Resume" : "Pause"}
+              {paused ? t("resume") : t("pause")}
             </Button>
             <Button
               variant="outline"
@@ -166,7 +170,7 @@ export function EventsPage() {
               onClick={clear}
               className="h-8 gap-1.5"
             >
-              <Trash2 className="h-3.5 w-3.5" /> Clear
+              <Trash2 className="h-3.5 w-3.5" /> {t("clear")}
             </Button>
           </>
         }
@@ -176,18 +180,18 @@ export function EventsPage() {
       <div className="mt-4 flex flex-wrap items-center gap-3">
         {/* Category pills */}
         <div className="flex flex-wrap items-center gap-1.5">
-          {EVENT_CATEGORIES.map((cat) => (
+          {EVENT_CATEGORY_VALUES.map((val) => (
             <button
-              key={cat.value}
+              key={val}
               type="button"
-              onClick={() => setCategoryFilter(cat.value)}
+              onClick={() => setCategoryFilter(val)}
               className={`rounded-full px-2.5 py-0.5 text-xs transition-colors ${
-                categoryFilter === cat.value
+                categoryFilter === val
                   ? "bg-primary text-primary-foreground"
                   : "text-muted-foreground hover:bg-muted"
               }`}
             >
-              {cat.label}
+              {t(CATEGORY_KEY_MAP[val] ?? val)}
             </button>
           ))}
         </div>
@@ -199,7 +203,7 @@ export function EventsPage() {
             onChange={(e) => setTeamFilter(e.target.value)}
             className="h-7 rounded-md border bg-background px-2 text-xs"
           >
-            <option value="all">All teams</option>
+            <option value="all">{t("filters.allTeams")}</option>
             {uniqueTeams.map((id) => (
               <option key={id} value={id}>
                 {resolveTeam(id)}
@@ -214,7 +218,7 @@ export function EventsPage() {
           onChange={(e) => setUserFilter(e.target.value)}
           className="h-7 rounded-md border bg-background px-2 text-xs"
         >
-          <option value="all">All users</option>
+          <option value="all">{t("filters.allUsers")}</option>
           {uniqueUsers.map((uid) => (
             <option key={uid} value={uid}>
               {uid}
@@ -228,7 +232,7 @@ export function EventsPage() {
           onChange={(e) => setChatFilter(e.target.value)}
           className="h-7 rounded-md border bg-background px-2 text-xs"
         >
-          <option value="all">All chats</option>
+          <option value="all">{t("filters.allChats")}</option>
           {uniqueChats.map((cid) => (
             <option key={cid} value={cid}>
               {cid}
@@ -243,12 +247,8 @@ export function EventsPage() {
           <div className="px-4 py-12">
             <EmptyState
               icon={Radar}
-              title="No events yet"
-              description={
-                paused
-                  ? "Event capture is paused. Resume to see new events."
-                  : "Waiting for real-time events... Events will appear as agents work."
-              }
+              title={t("emptyTitle")}
+              description={paused ? t("emptyPaused") : t("emptyWaiting")}
             />
           </div>
         ) : (
@@ -269,7 +269,7 @@ export function EventsPage() {
                 type="button"
                 onClick={scrollToBottom}
                 className="absolute bottom-4 right-4 flex h-8 w-8 items-center justify-center rounded-full border bg-background shadow-md transition-colors hover:bg-muted"
-                title="Scroll to bottom"
+                title={t("scrollToBottom")}
               >
                 <ArrowDown className="h-4 w-4" />
               </button>
diff --git a/ui/web/src/pages/login/login-page.tsx b/ui/web/src/pages/login/login-page.tsx
index 18e37bdf..8f44e480 100644
--- a/ui/web/src/pages/login/login-page.tsx
+++ b/ui/web/src/pages/login/login-page.tsx
@@ -1,5 +1,6 @@
 import { useState } from "react";
 import { useNavigate, useLocation } from "react-router";
+import { useTranslation } from "react-i18next";
 import { useAuthStore } from "@/stores/use-auth-store";
 import { ROUTES } from "@/lib/constants";
 import { LoginLayout } from "./login-layout";
@@ -8,6 +9,7 @@ import { TokenForm } from "./token-form";
 import { PairingForm } from "./pairing-form";
 
 export function LoginPage() {
+  const { t } = useTranslation("login");
   const [mode, setMode] = useState<LoginMode>("token");
 
   const setCredentials = useAuthStore((s) => s.setCredentials);
@@ -30,7 +32,7 @@ export function LoginPage() {
   }
 
   return (
-    <LoginLayout subtitle="Sign in to the gateway dashboard">
+    <LoginLayout subtitle={t("subtitle")}>
       <LoginTabs mode={mode} onModeChange={setMode} />
       {mode === "token" ? (
         <TokenForm onSubmit={handleTokenLogin} />
diff --git a/ui/web/src/pages/login/login-tabs.tsx b/ui/web/src/pages/login/login-tabs.tsx
index d05bd907..9ea67ff3 100644
--- a/ui/web/src/pages/login/login-tabs.tsx
+++ b/ui/web/src/pages/login/login-tabs.tsx
@@ -1,3 +1,5 @@
+import { useTranslation } from "react-i18next";
+
 export type LoginMode = "token" | "pairing";
 
 interface LoginTabsProps {
@@ -6,6 +8,7 @@ interface LoginTabsProps {
 }
 
 export function LoginTabs({ mode, onModeChange }: LoginTabsProps) {
+  const { t } = useTranslation("login");
   return (
     <div className="flex rounded-md border bg-muted p-1">
       <button
@@ -17,7 +20,7 @@ export function LoginTabs({ mode, onModeChange }: LoginTabsProps) {
             : "text-muted-foreground hover:text-foreground"
         }`}
       >
-        Token
+        {t("tabs.token")}
       </button>
       <button
         type="button"
@@ -28,7 +31,7 @@ export function LoginTabs({ mode, onModeChange }: LoginTabsProps) {
             : "text-muted-foreground hover:text-foreground"
         }`}
       >
-        Pairing
+        {t("tabs.pairing")}
       </button>
     </div>
   );
diff --git a/ui/web/src/pages/login/pairing-form.tsx b/ui/web/src/pages/login/pairing-form.tsx
index fb71f3ff..d33e13ea 100644
--- a/ui/web/src/pages/login/pairing-form.tsx
+++ b/ui/web/src/pages/login/pairing-form.tsx
@@ -1,4 +1,5 @@
 import { useState, useRef, useEffect, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Methods, PROTOCOL_VERSION } from "@/api/protocol";
 import { generateId } from "@/lib/utils";
 
@@ -9,6 +10,7 @@ interface PairingFormProps {
 }
 
 export function PairingForm({ onApproved }: PairingFormProps) {
+  const { t } = useTranslation("login");
   const [userId, setUserId] = useState("");
   const [code, setCode] = useState<string | null>(null);
   const [senderID, setSenderID] = useState<string | null>(null);
@@ -98,11 +100,11 @@ export function PairingForm({ onApproved }: PairingFormProps) {
 
     ws.onclose = () => {
       if (status === "pending") {
-        setError("Connection lost. Please try again.");
+        setError(t("pairing.errorConnectionLost"));
         setStatus("idle");
         setCode(null);
       } else if (status === "connecting") {
-        setError("Could not connect to gateway.");
+        setError(t("pairing.errorCannotConnect"));
         setStatus("idle");
       }
     };
@@ -144,7 +146,7 @@ export function PairingForm({ onApproved }: PairingFormProps) {
   if (status === "approved") {
     return (
       <p className="text-center text-sm text-green-600">
-        Access approved! Redirecting...
+        {t("pairing.approved")}
       </p>
     );
   }
@@ -158,22 +160,21 @@ export function PairingForm({ onApproved }: PairingFormProps) {
 
       <div className="space-y-2">
         <label htmlFor="pairingUserId" className="text-sm font-medium">
-          User ID
+          {t("pairing.userId")}
         </label>
         <input
           id="pairingUserId"
           type="text"
           value={userId}
           onChange={(e) => setUserId(e.target.value)}
-          placeholder="your-user-id"
+          placeholder={t("pairing.userIdPlaceholder")}
           className="flex h-9 w-full rounded-md border border-input bg-transparent px-3 py-1 text-sm shadow-sm transition-colors placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
           autoFocus
         />
       </div>
 
       <p className="text-xs text-muted-foreground">
-        No token needed. A pairing code will be generated for an admin to
-        approve.
+        {t("pairing.noTokenNeeded")}
       </p>
 
       <button
@@ -181,7 +182,7 @@ export function PairingForm({ onApproved }: PairingFormProps) {
         disabled={!userId.trim() || status === "connecting"}
         className="inline-flex h-9 w-full items-center justify-center rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground shadow transition-colors hover:bg-primary/90 disabled:pointer-events-none disabled:opacity-50"
       >
-        {status === "connecting" ? "Connecting..." : "Request Access"}
+        {status === "connecting" ? t("pairing.connecting") : t("pairing.requestAccess")}
       </button>
     </form>
   );
@@ -194,10 +195,11 @@ function PairingCodeDisplay({
   code: string;
   onCancel: () => void;
 }) {
+  const { t } = useTranslation("login");
   return (
     <div className="space-y-4">
       <p className="text-center text-sm text-muted-foreground">
-        Ask an admin to approve this code:
+        {t("pairing.askAdmin")}
       </p>
 
       <div className="flex justify-center gap-1.5">
@@ -212,7 +214,7 @@ function PairingCodeDisplay({
       </div>
 
       <p className="text-center text-xs text-muted-foreground">
-        Or run:{" "}
+        {t("pairing.orRun")}{" "}
         <code className="rounded bg-muted px-1.5 py-0.5">
           goclaw pairing approve {code}
         </code>
@@ -220,7 +222,7 @@ function PairingCodeDisplay({
 
       <div className="flex items-center justify-center gap-2 text-sm text-muted-foreground">
         <span className="inline-block h-2 w-2 animate-pulse rounded-full bg-amber-500" />
-        Waiting for approval...
+        {t("pairing.waitingForApproval")}
       </div>
 
       <button
@@ -228,7 +230,7 @@ function PairingCodeDisplay({
         onClick={onCancel}
         className="inline-flex h-9 w-full items-center justify-center rounded-md border px-4 py-2 text-sm font-medium transition-colors hover:bg-accent"
       >
-        Cancel
+        {t("pairing.cancel")}
       </button>
     </div>
   );
diff --git a/ui/web/src/pages/login/token-form.tsx b/ui/web/src/pages/login/token-form.tsx
index d4801f6a..56279c31 100644
--- a/ui/web/src/pages/login/token-form.tsx
+++ b/ui/web/src/pages/login/token-form.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { AlertCircle } from "lucide-react";
 
 interface TokenFormProps {
@@ -6,6 +7,7 @@ interface TokenFormProps {
 }
 
 export function TokenForm({ onSubmit }: TokenFormProps) {
+  const { t } = useTranslation("login");
   const [userId, setUserId] = useState("");
   const [token, setToken] = useState("");
   const [connecting, setConnecting] = useState(false);
@@ -28,18 +30,18 @@ export function TokenForm({ onSubmit }: TokenFormProps) {
       });
 
       if (res.status === 401) {
-        setError("Invalid credentials. Check your token and user ID.");
+        setError(t("token.errorInvalidCredentials"));
         return;
       }
 
       if (!res.ok) {
-        setError(`Server returned ${res.status}. Please try again.`);
+        setError(t("token.errorServer", { status: res.status }));
         return;
       }
 
       onSubmit(userId.trim(), token.trim());
     } catch {
-      setError("Cannot connect to gateway. Check if the server is running.");
+      setError(t("token.errorCannotConnect"));
     } finally {
       setConnecting(false);
     }
@@ -49,14 +51,14 @@ export function TokenForm({ onSubmit }: TokenFormProps) {
     <form onSubmit={handleSubmit} className="space-y-4">
       <div className="space-y-2">
         <label htmlFor="userId" className="text-sm font-medium">
-          User ID
+          {t("token.userId")}
         </label>
         <input
           id="userId"
           type="text"
           value={userId}
           onChange={(e) => { setUserId(e.target.value); setError(null); }}
-          placeholder="your-user-id"
+          placeholder={t("token.userIdPlaceholder")}
           className="flex h-9 w-full rounded-md border border-input bg-transparent px-3 py-1 text-sm shadow-sm transition-colors placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
           autoFocus
           disabled={connecting}
@@ -65,14 +67,14 @@ export function TokenForm({ onSubmit }: TokenFormProps) {
 
       <div className="space-y-2">
         <label htmlFor="token" className="text-sm font-medium">
-          Gateway Token
+          {t("token.gatewayToken")}
         </label>
         <input
           id="token"
           type="password"
           value={token}
           onChange={(e) => { setToken(e.target.value); setError(null); }}
-          placeholder="Bearer token"
+          placeholder={t("token.tokenPlaceholder")}
           className="flex h-9 w-full rounded-md border border-input bg-transparent px-3 py-1 text-sm shadow-sm transition-colors placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-ring"
           disabled={connecting}
         />
@@ -90,7 +92,7 @@ export function TokenForm({ onSubmit }: TokenFormProps) {
         disabled={!token.trim() || !userId.trim() || connecting}
         className="inline-flex h-9 w-full items-center justify-center rounded-md bg-primary px-4 py-2 text-sm font-medium text-primary-foreground shadow transition-colors hover:bg-primary/90 disabled:pointer-events-none disabled:opacity-50"
       >
-        {connecting ? "Connecting..." : "Connect"}
+        {connecting ? t("token.connecting") : t("token.connect")}
       </button>
     </form>
   );
diff --git a/ui/web/src/pages/logs/logs-page.tsx b/ui/web/src/pages/logs/logs-page.tsx
index ca62251b..1fb56c99 100644
--- a/ui/web/src/pages/logs/logs-page.tsx
+++ b/ui/web/src/pages/logs/logs-page.tsx
@@ -1,5 +1,6 @@
 import { useEffect, useRef, useState, useMemo } from "react";
 import { Terminal, Play, Square, Trash2, Search } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { PageHeader } from "@/components/shared/page-header";
@@ -15,6 +16,7 @@ const levelColors: Record<string, string> = {
 const levels: LogLevel[] = ["debug", "info", "warn", "error"];
 
 export function LogsPage() {
+  const { t } = useTranslation("logs");
   const { logs, tailing, level, error, startTail, stopTail, clearLogs } =
     useLogs();
   const scrollRef = useRef<HTMLDivElement>(null);
@@ -45,15 +47,15 @@ export function LogsPage() {
   return (
     <div className="flex h-full flex-col p-6">
       <PageHeader
-        title="Logs"
+        title={t("title")}
         description={
           tailing
-            ? `Live tailing at ${level} level`
-            : "Live log tailing"
+            ? t("descriptionLive", { level })
+            : t("description")
         }
         actions={
           <div className="flex items-center gap-2">
-            {tailing && <Badge variant="success">Live</Badge>}
+            {tailing && <Badge variant="success">{t("live")}</Badge>}
             {tailing ? (
               <Button
                 variant="outline"
@@ -61,7 +63,7 @@ export function LogsPage() {
                 onClick={stopTail}
                 className="gap-1"
               >
-                <Square className="h-3.5 w-3.5" /> Stop
+                <Square className="h-3.5 w-3.5" /> {t("stop")}
               </Button>
             ) : (
               <div className="flex items-center gap-1">
@@ -69,7 +71,7 @@ export function LogsPage() {
                   value={level}
                   onChange={(e) => startTail(e.target.value as LogLevel)}
                   className="h-8 cursor-pointer rounded-md border bg-background px-2 text-xs"
-                  title="Log level"
+                  title={t("logLevelTitle")}
                 >
                   {levels.map((l) => (
                     <option key={l} value={l}>
@@ -82,7 +84,7 @@ export function LogsPage() {
                   onClick={() => startTail()}
                   className="gap-1"
                 >
-                  <Play className="h-3.5 w-3.5" /> Start
+                  <Play className="h-3.5 w-3.5" /> {t("start")}
                 </Button>
               </div>
             )}
@@ -93,7 +95,7 @@ export function LogsPage() {
               disabled={logs.length === 0}
               className="gap-1"
             >
-              <Trash2 className="h-3.5 w-3.5" /> Clear
+              <Trash2 className="h-3.5 w-3.5" /> {t("clear")}
             </Button>
           </div>
         }
@@ -107,7 +109,7 @@ export function LogsPage() {
             type="text"
             value={search}
             onChange={(e) => setSearch(e.target.value)}
-            placeholder="Filter logs..."
+            placeholder={t("filterPlaceholder")}
             className="h-7 w-full rounded-md border bg-background pl-8 pr-3 text-xs placeholder:text-muted-foreground focus:outline-none focus:ring-1 focus:ring-ring"
           />
         </div>
@@ -127,7 +129,7 @@ export function LogsPage() {
           ))}
         </div>
         <span className="text-xs text-muted-foreground">
-          {filtered.length}/{logs.length}
+          {t("count", { filtered: filtered.length, total: logs.length })}
         </span>
       </div>
 
@@ -150,9 +152,9 @@ export function LogsPage() {
               <p>
                 {tailing
                   ? search
-                    ? "No logs match filter."
-                    : "Waiting for logs..."
-                  : 'Click "Start" to begin streaming logs.'}
+                    ? t("emptyFilter")
+                    : t("emptyWaiting")
+                  : t("emptyStart")}
               </p>
             </div>
           </div>
diff --git a/ui/web/src/pages/mcp/hooks/use-mcp.ts b/ui/web/src/pages/mcp/hooks/use-mcp.ts
index 2369345f..66e39572 100644
--- a/ui/web/src/pages/mcp/hooks/use-mcp.ts
+++ b/ui/web/src/pages/mcp/hooks/use-mcp.ts
@@ -1,5 +1,6 @@
 import { useCallback } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
+import i18next from "i18next";
 import { useHttp } from "@/hooks/use-ws";
 import { queryKeys } from "@/lib/query-keys";
 import { toast } from "@/stores/use-toast-store";
@@ -29,10 +30,10 @@ export function useMCP() {
       try {
         const res = await http.post<MCPServerData>("/v1/mcp/servers", data);
         await invalidate();
-        toast.success("MCP server created", `${data.name} has been added`);
+        toast.success(i18next.t("mcp:toast.created"));
         return res;
       } catch (err) {
-        toast.error("Failed to create MCP server", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("mcp:toast.failedCreate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -44,9 +45,9 @@ export function useMCP() {
       try {
         await http.put(`/v1/mcp/servers/${id}`, data);
         await invalidate();
-        toast.success("MCP server updated");
+        toast.success(i18next.t("mcp:toast.updated"));
       } catch (err) {
-        toast.error("Failed to update MCP server", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("mcp:toast.failedUpdate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -58,9 +59,9 @@ export function useMCP() {
       try {
         await http.delete(`/v1/mcp/servers/${id}`);
         await invalidate();
-        toast.success("MCP server deleted");
+        toast.success(i18next.t("mcp:toast.deleted"));
       } catch (err) {
-        toast.error("Failed to delete MCP server", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("mcp:toast.failedDelete"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
diff --git a/ui/web/src/pages/mcp/mcp-form-dialog.tsx b/ui/web/src/pages/mcp/mcp-form-dialog.tsx
index accaa723..adf29678 100644
--- a/ui/web/src/pages/mcp/mcp-form-dialog.tsx
+++ b/ui/web/src/pages/mcp/mcp-form-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Loader2, CheckCircle2, XCircle } from "lucide-react";
 import {
   Dialog,
@@ -30,6 +31,7 @@ const TRANSPORTS = [
 ];
 
 export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }: MCPFormDialogProps) {
+  const { t } = useTranslation("mcp");
   const [name, setName] = useState("");
   const [displayName, setDisplayName] = useState("");
   const [transport, setTransport] = useState("stdio");
@@ -84,11 +86,11 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
 
   const handleTest = async () => {
     if (isStdio && !command.trim()) {
-      setError("Command is required for stdio transport");
+      setError(t("form.errors.commandRequired"));
       return;
     }
     if (!isStdio && !url.trim()) {
-      setError("URL is required for SSE/HTTP transport");
+      setError(t("form.errors.urlRequired"));
       return;
     }
 
@@ -99,7 +101,7 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
       const result = await onTest(buildConnectionData());
       setTestResult(result);
     } catch (err: unknown) {
-      setTestResult({ success: false, error: err instanceof Error ? err.message : "Connection failed" });
+      setTestResult({ success: false, error: err instanceof Error ? err.message : t("form.errors.connectionFailed") });
     } finally {
       setTesting(false);
     }
@@ -107,19 +109,19 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
 
   const handleSubmit = async () => {
     if (!name.trim() || !transport) {
-      setError("Name and transport are required");
+      setError(t("form.errors.nameRequired"));
       return;
     }
     if (!isValidSlug(name.trim())) {
-      setError("Name must be a valid slug (lowercase letters, numbers, hyphens only)");
+      setError(t("form.errors.nameSlug"));
       return;
     }
     if (isStdio && !command.trim()) {
-      setError("Command is required for stdio transport");
+      setError(t("form.errors.commandRequired"));
       return;
     }
     if (!isStdio && !url.trim()) {
-      setError("URL is required for SSE/HTTP transport");
+      setError(t("form.errors.urlRequired"));
       return;
     }
 
@@ -137,7 +139,7 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
       });
       onOpenChange(false);
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Failed to save");
+      setError(err instanceof Error ? err.message : t("form.saving"));
     } finally {
       setLoading(false);
     }
@@ -147,33 +149,33 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
     <Dialog open={open} onOpenChange={(v) => !loading && onOpenChange(v)}>
       <DialogContent className="max-h-[85vh] flex flex-col sm:max-w-xl">
         <DialogHeader>
-          <DialogTitle>{server ? "Edit MCP Server" : "Add MCP Server"}</DialogTitle>
+          <DialogTitle>{server ? t("form.editTitle") : t("form.createTitle")}</DialogTitle>
         </DialogHeader>
 
         <div className="grid gap-4 py-2 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
           <div className="grid gap-1.5">
-            <Label htmlFor="mcp-name">Name *</Label>
+            <Label htmlFor="mcp-name">{t("form.name")}</Label>
             <Input id="mcp-name" value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder="my-mcp-server" />
-            <p className="text-xs text-muted-foreground">Lowercase letters, numbers, and hyphens only</p>
+            <p className="text-xs text-muted-foreground">{t("form.nameHint")}</p>
           </div>
 
           <div className="grid gap-1.5">
-            <Label htmlFor="mcp-display">Display Name</Label>
+            <Label htmlFor="mcp-display">{t("form.displayName")}</Label>
             <Input id="mcp-display" value={displayName} onChange={(e) => setDisplayName(e.target.value)} placeholder="My MCP Server" />
           </div>
 
           <div className="grid gap-1.5">
-            <Label>Transport *</Label>
+            <Label>{t("form.transport")}</Label>
             <div className="flex gap-2">
-              {TRANSPORTS.map((t) => (
+              {TRANSPORTS.map((tr) => (
                 <Button
-                  key={t.value}
+                  key={tr.value}
                   type="button"
-                  variant={transport === t.value ? "default" : "outline"}
+                  variant={transport === tr.value ? "default" : "outline"}
                   size="sm"
-                  onClick={() => setTransport(t.value)}
+                  onClick={() => setTransport(tr.value)}
                 >
-                  {t.label}
+                  {tr.label}
                 </Button>
               ))}
             </div>
@@ -182,61 +184,61 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
           {isStdio ? (
             <>
               <div className="grid gap-1.5">
-                <Label htmlFor="mcp-cmd">Command *</Label>
+                <Label htmlFor="mcp-cmd">{t("form.command")}</Label>
                 <Input id="mcp-cmd" value={command} onChange={(e) => setCommand(e.target.value)} placeholder="npx -y @modelcontextprotocol/server-everything" className="font-mono text-sm" />
               </div>
               <div className="grid gap-1.5">
-                <Label htmlFor="mcp-args">Args (comma-separated)</Label>
-                <Input id="mcp-args" value={args} onChange={(e) => setArgs(e.target.value)} placeholder="--flag1, --flag2" className="font-mono text-sm" />
+                <Label htmlFor="mcp-args">{t("form.args")}</Label>
+                <Input id="mcp-args" value={args} onChange={(e) => setArgs(e.target.value)} placeholder={t("form.argsPlaceholder")} className="font-mono text-sm" />
               </div>
             </>
           ) : (
             <>
               <div className="grid gap-1.5">
-                <Label htmlFor="mcp-url">URL *</Label>
+                <Label htmlFor="mcp-url">{t("form.url")}</Label>
                 <Input id="mcp-url" value={url} onChange={(e) => setUrl(e.target.value)} placeholder="http://localhost:3001/sse" className="font-mono text-sm" />
               </div>
               <div className="grid gap-1.5">
-                <Label>Headers</Label>
+                <Label>{t("form.headers")}</Label>
                 <KeyValueEditor
                   value={headers}
                   onChange={setHeaders}
-                  keyPlaceholder="Header name"
-                  valuePlaceholder="Header value"
-                  addLabel="Add Header"
+                  keyPlaceholder={t("form.headerKeyPlaceholder")}
+                  valuePlaceholder={t("form.headerValuePlaceholder")}
+                  addLabel={t("form.addHeader")}
                 />
               </div>
             </>
           )}
 
           <div className="grid gap-1.5">
-            <Label>Environment Variables</Label>
+            <Label>{t("form.env")}</Label>
             <KeyValueEditor
               value={env}
               onChange={setEnv}
-              keyPlaceholder="Variable name"
-              valuePlaceholder="Value"
-              addLabel="Add Variable"
+              keyPlaceholder={t("form.envKeyPlaceholder")}
+              valuePlaceholder={t("form.envValuePlaceholder")}
+              addLabel={t("form.addVariable")}
             />
           </div>
 
           <div className="grid gap-1.5">
-            <Label htmlFor="mcp-prefix">Tool Prefix</Label>
+            <Label htmlFor="mcp-prefix">{t("form.toolPrefix")}</Label>
             <div className="flex">
               <span className="inline-flex items-center px-2.5 rounded-l-md border border-r-0 border-input bg-muted text-muted-foreground text-sm font-mono">mcp_</span>
               <Input id="mcp-prefix" value={toolPrefix} onChange={(e) => setToolPrefix(e.target.value.replace(/[^a-z0-9_]/g, ""))} placeholder={name.replace(/-/g, "_") || "auto"} className="rounded-l-none font-mono text-sm" />
             </div>
-            <p className="text-xs text-muted-foreground">Auto-derived from name if empty. Tools: <code className="text-[10px]">mcp_&#123;prefix&#125;__&#123;tool&#125;</code></p>
+            <p className="text-xs text-muted-foreground">{t("form.toolPrefixHint")} Tools: <code className="text-[10px]">mcp_&#123;prefix&#125;__&#123;tool&#125;</code></p>
           </div>
 
           <div className="grid gap-1.5">
-            <Label htmlFor="mcp-timeout">Timeout (seconds)</Label>
+            <Label htmlFor="mcp-timeout">{t("form.timeout")}</Label>
             <Input id="mcp-timeout" type="number" value={timeout} onChange={(e) => setTimeout(Number(e.target.value))} min={1} />
           </div>
 
           <div className="flex items-center gap-2">
             <Switch id="mcp-enabled" checked={enabled} onCheckedChange={setEnabled} />
-            <Label htmlFor="mcp-enabled">Enabled</Label>
+            <Label htmlFor="mcp-enabled">{t("form.enabled")}</Label>
           </div>
           {error && <p className="text-sm text-destructive">{error}</p>}
         </div>
@@ -244,12 +246,12 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
         <DialogFooter className="flex-col sm:flex-row gap-2">
           <div className="flex items-center gap-2 mr-auto">
             <Button type="button" variant="secondary" size="sm" onClick={handleTest} disabled={loading || testing}>
-              {testing ? <><Loader2 className="h-3.5 w-3.5 animate-spin mr-1" /> Testing...</> : "Test Connection"}
+              {testing ? <><Loader2 className="h-3.5 w-3.5 animate-spin mr-1" /> {t("form.testing")}</> : t("form.testConnection")}
             </Button>
             {testResult && (
               <span className={`flex items-center gap-1 text-xs ${testResult.success ? "text-emerald-600 dark:text-emerald-400" : "text-destructive"}`}>
                 {testResult.success ? (
-                  <><CheckCircle2 className="h-3.5 w-3.5" /> {testResult.tool_count} tools found</>
+                  <><CheckCircle2 className="h-3.5 w-3.5" /> {t("form.toolsFound", { count: testResult.tool_count })}</>
                 ) : (
                   <><XCircle className="h-3.5 w-3.5" /> {testResult.error}</>
                 )}
@@ -257,9 +259,9 @@ export function MCPFormDialog({ open, onOpenChange, server, onSubmit, onTest }:
             )}
           </div>
           <div className="flex gap-2">
-            <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>Cancel</Button>
+            <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>{t("form.cancel")}</Button>
             <Button onClick={handleSubmit} disabled={loading}>
-              {loading ? "Saving..." : server ? "Update" : "Create"}
+              {loading ? t("form.saving") : server ? t("form.update") : t("form.create")}
             </Button>
           </div>
         </DialogFooter>
diff --git a/ui/web/src/pages/mcp/mcp-grants-dialog.tsx b/ui/web/src/pages/mcp/mcp-grants-dialog.tsx
index 4250dc3b..ceee42f6 100644
--- a/ui/web/src/pages/mcp/mcp-grants-dialog.tsx
+++ b/ui/web/src/pages/mcp/mcp-grants-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useMemo, useRef, useLayoutEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { createPortal } from "react-dom";
 import { Trash2, Plus, X, ChevronDownIcon, Pencil } from "lucide-react";
 import {
@@ -40,6 +41,7 @@ export function MCPGrantsDialog({
   onLoadGrants,
   onLoadTools,
 }: MCPGrantsDialogProps) {
+  const { t } = useTranslation("mcp");
   const { agents } = useAgents();
   const portalRef = useRef<HTMLDivElement>(null);
   const [agentId, setAgentId] = useState("");
@@ -98,7 +100,7 @@ export function MCPGrantsDialog({
 
   const handleGrant = async () => {
     if (!agentId) {
-      setError("Agent is required");
+      setError(t("grants.agentRequired"));
       return;
     }
 
@@ -136,7 +138,7 @@ export function MCPGrantsDialog({
       }
       clearForm();
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Failed to grant");
+      setError(err instanceof Error ? err.message : t("grants.failedGrant"));
     } finally {
       setLoading(false);
     }
@@ -148,7 +150,7 @@ export function MCPGrantsDialog({
       await onRevoke(grant.agent_id);
       setGrants((prev) => prev.filter((g) => g.agent_id !== grant.agent_id));
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Failed to revoke");
+      setError(err instanceof Error ? err.message : t("grants.failedRevoke"));
     } finally {
       setLoading(false);
     }
@@ -158,14 +160,14 @@ export function MCPGrantsDialog({
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-h-[85vh] flex flex-col sm:max-w-xl">
         <DialogHeader>
-          <DialogTitle>Agent Grants - {server.display_name || server.name}</DialogTitle>
+          <DialogTitle>{t("grants.title", { name: server.display_name || server.name })}</DialogTitle>
         </DialogHeader>
 
         <div className="space-y-4 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
           {/* Existing grants */}
           {grants.length > 0 && (
             <div className="space-y-2">
-              <Label>Current Grants</Label>
+              <Label>{t("grants.currentGrants")}</Label>
               <div className="grid gap-2">
                 {grants.map((grant) => {
                   const hasAllow = Array.isArray(grant.tool_allow) && grant.tool_allow.length > 0;
@@ -209,7 +211,7 @@ export function MCPGrantsDialog({
                             </div>
                           )}
                           {!hasAllow && !hasDeny && (
-                            <p className="text-xs text-muted-foreground mt-0.5">All tools allowed</p>
+                            <p className="text-xs text-muted-foreground mt-0.5">{t("grants.allToolsAllowed")}</p>
                           )}
                         </div>
                         <Button
@@ -233,18 +235,18 @@ export function MCPGrantsDialog({
           <div className="space-y-3 rounded-md border p-3">
             <div className="flex items-center justify-between">
               <Label className="text-sm font-medium">
-                {isEditing ? "Edit Grant" : "Add Agent Grant"}
+                {isEditing ? t("grants.editGrant") : t("grants.addGrant")}
               </Label>
               {isEditing && (
                 <Button variant="ghost" size="sm" onClick={clearForm} className="h-6 px-2 text-xs text-muted-foreground">
-                  Cancel
+                  {t("grants.cancel")}
                 </Button>
               )}
             </div>
             <div className="grid gap-2">
               <Select value={agentId} onValueChange={setAgentId} disabled={isEditing}>
                 <SelectTrigger>
-                  <SelectValue placeholder="Select agent..." />
+                  <SelectValue placeholder={t("grants.selectAgent")} />
                 </SelectTrigger>
                 <SelectContent>
                   {agents.map((a) => (
@@ -257,32 +259,32 @@ export function MCPGrantsDialog({
               </Select>
 
               <div className="grid gap-1">
-                <Label className="text-xs text-muted-foreground">Tool allow list (optional)</Label>
+                <Label className="text-xs text-muted-foreground">{t("grants.toolAllowList")}</Label>
                 <ToolMultiSelect
                   value={toolAllow}
                   onChange={setToolAllow}
                   options={serverTools}
-                  placeholder="Select tools to allow..."
+                  placeholder={t("grants.allowPlaceholder")}
                   portalContainer={portalRef}
                 />
               </div>
 
               <div className="grid gap-1">
-                <Label className="text-xs text-muted-foreground">Tool deny list (optional)</Label>
+                <Label className="text-xs text-muted-foreground">{t("grants.toolDenyList")}</Label>
                 <ToolMultiSelect
                   value={toolDeny}
                   onChange={setToolDeny}
                   options={serverTools}
-                  placeholder="Select tools to deny..."
+                  placeholder={t("grants.denyPlaceholder")}
                   portalContainer={portalRef}
                 />
               </div>
             </div>
             <Button size="sm" onClick={handleGrant} disabled={loading || !agentId} className="gap-1">
               {isEditing ? (
-                <><Pencil className="h-3.5 w-3.5" /> Update</>
+                <><Pencil className="h-3.5 w-3.5" /> {t("grants.update")}</>
               ) : (
-                <><Plus className="h-3.5 w-3.5" /> Grant</>
+                <><Plus className="h-3.5 w-3.5" /> {t("grants.grant")}</>
               )}
             </Button>
           </div>
diff --git a/ui/web/src/pages/mcp/mcp-page.tsx b/ui/web/src/pages/mcp/mcp-page.tsx
index c19e3990..3ad18b5e 100644
--- a/ui/web/src/pages/mcp/mcp-page.tsx
+++ b/ui/web/src/pages/mcp/mcp-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Plug, Plus, RefreshCw, Pencil, Trash2, Users, Wrench } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -23,6 +24,8 @@ const transportBadge: Record<string, string> = {
 };
 
 export function MCPPage() {
+  const { t } = useTranslation("mcp");
+  const { t: tc } = useTranslation("common");
   const { servers, loading, refresh, createServer, updateServer, deleteServer, grantAgent, revokeAgent, listAgentGrants, testConnection, listServerTools } = useMCP();
   const spinning = useMinLoading(loading);
   const showSkeleton = useDeferredLoading(loading && servers.length === 0);
@@ -67,15 +70,15 @@ export function MCPPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="MCP Servers"
-        description="Manage Model Context Protocol server connections"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex gap-2">
             <Button size="sm" onClick={() => { setEditServer(null); setFormOpen(true); }} className="gap-1">
-              <Plus className="h-3.5 w-3.5" /> Add Server
+              <Plus className="h-3.5 w-3.5" /> {t("addServer")}
             </Button>
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
             </Button>
           </div>
         }
@@ -85,7 +88,7 @@ export function MCPPage() {
         <SearchInput
           value={search}
           onChange={setSearch}
-          placeholder="Search servers..."
+          placeholder={t("searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -96,20 +99,20 @@ export function MCPPage() {
         ) : filtered.length === 0 ? (
           <EmptyState
             icon={Plug}
-            title={search ? "No matching servers" : "No MCP servers"}
-            description={search ? "Try a different search term." : "Add your first MCP server to get started."}
+            title={search ? t("noMatchTitle") : t("emptyTitle")}
+            description={search ? t("noMatchDescription") : t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Name</th>
-                  <th className="px-4 py-3 text-left font-medium">Transport</th>
-                  <th className="px-4 py-3 text-center font-medium">Tools</th>
-                  <th className="px-4 py-3 text-left font-medium">Enabled</th>
-                  <th className="px-4 py-3 text-left font-medium">Created By</th>
-                  <th className="px-4 py-3 text-right font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.name")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.transport")}</th>
+                  <th className="px-4 py-3 text-center font-medium">{t("columns.tools")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.enabled")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.createdBy")}</th>
+                  <th className="px-4 py-3 text-right font-medium">{t("columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -141,14 +144,14 @@ export function MCPPage() {
                         variant="ghost"
                         size="sm"
                         onClick={() => setToolsServer(srv)}
-                        title="View tools"
+                        title={t("viewTools")}
                       >
                         <Wrench className="h-3.5 w-3.5" />
                       </Button>
                     </td>
                     <td className="px-4 py-3">
                       <Badge variant={srv.enabled ? "default" : "secondary"}>
-                        {srv.enabled ? "Yes" : "No"}
+                        {srv.enabled ? tc("yes") : tc("no")}
                       </Badge>
                     </td>
                     <td className="px-4 py-3 text-muted-foreground">{srv.created_by || "-"}</td>
@@ -159,7 +162,7 @@ export function MCPPage() {
                           size="sm"
                           onClick={() => setGrantsServer(srv)}
                           className="gap-1"
-                          title="Manage grants"
+                          title={t("manageGrants")}
                         >
                           <Users className="h-3.5 w-3.5" />
                         </Button>
@@ -229,10 +232,10 @@ export function MCPPage() {
       <ConfirmDeleteDialog
         open={!!deleteTarget}
         onOpenChange={(open) => !open && setDeleteTarget(null)}
-        title="Delete MCP Server"
-        description={`Are you sure you want to delete "${deleteTarget?.display_name || deleteTarget?.name}"? This will also remove all associated grants.`}
+        title={t("delete.title")}
+        description={t("delete.description", { name: deleteTarget?.display_name || deleteTarget?.name })}
         confirmValue={deleteTarget?.display_name || deleteTarget?.name || ""}
-        confirmLabel="Delete"
+        confirmLabel={t("delete.confirmLabel")}
         onConfirm={handleDelete}
         loading={deleteLoading}
       />
diff --git a/ui/web/src/pages/mcp/mcp-tools-dialog.tsx b/ui/web/src/pages/mcp/mcp-tools-dialog.tsx
index 193d70aa..502322ce 100644
--- a/ui/web/src/pages/mcp/mcp-tools-dialog.tsx
+++ b/ui/web/src/pages/mcp/mcp-tools-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Loader2, Wrench, Search } from "lucide-react";
 import {
   Dialog,
@@ -18,6 +19,7 @@ interface MCPToolsDialogProps {
 }
 
 export function MCPToolsDialog({ open, onOpenChange, server, onLoadTools }: MCPToolsDialogProps) {
+  const { t } = useTranslation("mcp");
   const [tools, setTools] = useState<MCPToolInfo[]>([]);
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState("");
@@ -30,7 +32,7 @@ export function MCPToolsDialog({ open, onOpenChange, server, onLoadTools }: MCPT
     setSearch("");
     onLoadTools(server.id)
       .then(setTools)
-      .catch(() => setError("Failed to load tools"))
+      .catch(() => setError(t("tools.failedLoad")))
       .finally(() => setLoading(false));
   }, [open, server.id, onLoadTools]);
 
@@ -46,17 +48,17 @@ export function MCPToolsDialog({ open, onOpenChange, server, onLoadTools }: MCPT
         <DialogHeader>
           <DialogTitle className="flex items-center gap-2">
             <Wrench className="h-4 w-4" />
-            Tools — {server.display_name || server.name}
+            {t("tools.title", { name: server.display_name || server.name })}
           </DialogTitle>
           <p className="text-xs text-muted-foreground font-mono mt-1">
-            prefix: {prefix}
+            {t("tools.prefix")} {prefix}
           </p>
         </DialogHeader>
 
         {loading ? (
           <div className="flex flex-col items-center justify-center py-12 gap-2 text-muted-foreground">
             <Loader2 className="h-6 w-6 animate-spin" />
-            <span className="text-sm">Discovering tools...</span>
+            <span className="text-sm">{t("tools.discovering")}</span>
           </div>
         ) : error ? (
           <div className="flex flex-col items-center justify-center py-12 gap-2">
@@ -65,8 +67,8 @@ export function MCPToolsDialog({ open, onOpenChange, server, onLoadTools }: MCPT
         ) : tools.length === 0 ? (
           <div className="flex flex-col items-center justify-center py-12 gap-2 text-muted-foreground">
             <Wrench className="h-8 w-8 opacity-40" />
-            <p className="text-sm">No tools discovered</p>
-            <p className="text-xs">The server may be offline or has no tools registered.</p>
+            <p className="text-sm">{t("tools.noToolsTitle")}</p>
+            <p className="text-xs">{t("tools.noToolsDescription")}</p>
           </div>
         ) : (
           <div className="flex flex-col gap-3 min-h-0">
@@ -76,7 +78,7 @@ export function MCPToolsDialog({ open, onOpenChange, server, onLoadTools }: MCPT
                 <Input
                   value={search}
                   onChange={(e) => setSearch(e.target.value)}
-                  placeholder="Filter tools..."
+                  placeholder={t("tools.filterPlaceholder")}
                   className="pl-8 h-8 text-sm"
                 />
               </div>
@@ -87,7 +89,7 @@ export function MCPToolsDialog({ open, onOpenChange, server, onLoadTools }: MCPT
 
             <div className="overflow-y-auto min-h-0 -mx-1 px-1 max-h-[50vh]">
               {filtered.length === 0 ? (
-                <p className="text-sm text-muted-foreground text-center py-6">No matching tools</p>
+                <p className="text-sm text-muted-foreground text-center py-6">{t("tools.noMatch")}</p>
               ) : (
                 <div className="grid gap-1.5">
                   {filtered.map((tool) => (
diff --git a/ui/web/src/pages/memory/kg-entities-tab.tsx b/ui/web/src/pages/memory/kg-entities-tab.tsx
index ec07a31a..a1a885cc 100644
--- a/ui/web/src/pages/memory/kg-entities-tab.tsx
+++ b/ui/web/src/pages/memory/kg-entities-tab.tsx
@@ -6,6 +6,7 @@ import { Badge } from "@/components/ui/badge";
 import { EmptyState } from "@/components/shared/empty-state";
 import { TableSkeleton } from "@/components/shared/loading-skeleton";
 import { ConfirmDialog } from "@/components/shared/confirm-dialog";
+import { useTranslation } from "react-i18next";
 import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 import { useKnowledgeGraph, useKGStats, useKGGraph } from "./hooks/use-knowledge-graph";
 import { KGEntityDetailDialog } from "./kg-entity-detail-dialog";
@@ -21,6 +22,7 @@ interface KGEntitiesTabProps {
 type ViewMode = "table" | "graph";
 
 export function KGEntitiesTab({ agentId, userId }: KGEntitiesTabProps) {
+  const { t } = useTranslation("memory");
   const [searchQuery, setSearchQuery] = useState("");
   const [appliedQuery, setAppliedQuery] = useState("");
   const [viewEntity, setViewEntity] = useState<KGEntity | null>(null);
@@ -62,8 +64,8 @@ export function KGEntitiesTab({ agentId, userId }: KGEntitiesTabProps) {
       {/* Stats bar */}
       {stats && (
         <div className="flex gap-4 text-xs text-muted-foreground mb-3">
-          <span>Entities: {stats.entity_count}</span>
-          <span>Relations: {stats.relation_count}</span>
+          <span>{t("kg.stats.entities", { count: stats.entity_count })}</span>
+          <span>{t("kg.stats.relations", { count: stats.relation_count })}</span>
           {Object.entries(stats.entity_types).map(([type, count]) => (
             <span key={type}>{type}: {count}</span>
           ))}
@@ -76,15 +78,15 @@ export function KGEntitiesTab({ agentId, userId }: KGEntitiesTabProps) {
           value={searchQuery}
           onChange={(e) => setSearchQuery(e.target.value)}
           onKeyDown={handleKeyDown}
-          placeholder="Search entities..."
+          placeholder={t("kg.search.placeholder")}
           className="max-w-sm"
         />
         <Button variant="outline" size="sm" onClick={handleSearch} disabled={fetching} className="gap-1 h-9">
-          <Search className="h-3.5 w-3.5" /> Search
+          <Search className="h-3.5 w-3.5" /> {t("kg.search.button")}
         </Button>
         {appliedQuery && (
           <Button variant="ghost" size="sm" onClick={() => { setAppliedQuery(""); setSearchQuery(""); }} className="h-9">
-            Clear
+            {t("kg.search.clear")}
           </Button>
         )}
         <div className="flex-1" />
@@ -110,10 +112,10 @@ export function KGEntitiesTab({ agentId, userId }: KGEntitiesTabProps) {
         </div>
 
         <Button variant="outline" size="sm" onClick={() => refresh()} disabled={fetching} className="gap-1 h-9">
-          <RefreshCw className={"h-3.5 w-3.5" + (fetching ? " animate-spin" : "")} /> Refresh
+          <RefreshCw className={"h-3.5 w-3.5" + (fetching ? " animate-spin" : "")} /> {t("kg.refresh")}
         </Button>
         <Button variant="outline" size="sm" onClick={() => setExtractOpen(true)} className="gap-1 h-9">
-          <Sparkles className="h-3.5 w-3.5" /> Extract
+          <Sparkles className="h-3.5 w-3.5" /> {t("kg.extract")}
         </Button>
       </div>
 
@@ -129,19 +131,19 @@ export function KGEntitiesTab({ agentId, userId }: KGEntitiesTabProps) {
       ) : entities.length === 0 ? (
         <EmptyState
           icon={Network}
-          title="No entities"
-          description={appliedQuery ? "No entities match your search." : "No knowledge graph entities for this agent yet."}
+          title={t("kg.emptyTitle")}
+          description={appliedQuery ? t("kg.emptySearchDescription") : t("kg.emptyDescription")}
         />
       ) : (
         <div className="rounded-md border">
           <table className="w-full text-sm">
             <thead>
               <tr className="border-b bg-muted/50">
-                <th className="px-4 py-3 text-left font-medium">Name</th>
-                <th className="px-4 py-3 text-left font-medium">Type</th>
-                <th className="px-4 py-3 text-left font-medium">Description</th>
-                <th className="px-4 py-3 text-left font-medium">Confidence</th>
-                <th className="px-4 py-3 text-right font-medium">Actions</th>
+                <th className="px-4 py-3 text-left font-medium">{t("kg.columns.name")}</th>
+                <th className="px-4 py-3 text-left font-medium">{t("kg.columns.type")}</th>
+                <th className="px-4 py-3 text-left font-medium">{t("kg.columns.description")}</th>
+                <th className="px-4 py-3 text-left font-medium">{t("kg.columns.confidence")}</th>
+                <th className="px-4 py-3 text-right font-medium">{t("kg.columns.actions")}</th>
               </tr>
             </thead>
             <tbody>
@@ -207,9 +209,9 @@ export function KGEntitiesTab({ agentId, userId }: KGEntitiesTabProps) {
       <ConfirmDialog
         open={!!deleteTarget}
         onOpenChange={(open) => !open && setDeleteTarget(null)}
-        title="Delete Entity"
-        description={`Delete "${deleteTarget?.name}"? This will also delete all associated relations.`}
-        confirmLabel="Delete"
+        title={t("kg.deleteEntity.title")}
+        description={t("kg.deleteEntity.description", { name: deleteTarget?.name ?? "" })}
+        confirmLabel={t("kg.deleteEntity.confirmLabel")}
         variant="destructive"
         onConfirm={handleDelete}
         loading={deleteLoading}
diff --git a/ui/web/src/pages/memory/kg-entity-detail-dialog.tsx b/ui/web/src/pages/memory/kg-entity-detail-dialog.tsx
index bc927aaf..32cc8d7a 100644
--- a/ui/web/src/pages/memory/kg-entity-detail-dialog.tsx
+++ b/ui/web/src/pages/memory/kg-entity-detail-dialog.tsx
@@ -8,6 +8,7 @@ import {
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import { GitFork } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { useKGTraversal } from "./hooks/use-knowledge-graph";
 import type { KGEntity, KGRelation } from "@/types/knowledge-graph";
 
@@ -20,6 +21,7 @@ interface KGEntityDetailDialogProps {
 }
 
 export function KGEntityDetailDialog({ open, onOpenChange, agentId, entity, getEntityWithRelations }: KGEntityDetailDialogProps) {
+  const { t } = useTranslation("memory");
   const [relations, setRelations] = useState<KGRelation[]>([]);
   const [loadingRels, setLoadingRels] = useState(false);
   const { results: traversalResults, traversing, traverse } = useKGTraversal(agentId);
@@ -66,17 +68,29 @@ export function KGEntityDetailDialog({ open, onOpenChange, agentId, entity, getE
           {/* Entity info */}
           {entity && (
             <div className="grid grid-cols-2 gap-2 text-xs">
-              <div><span className="text-muted-foreground">External ID:</span> <span className="font-mono">{entity.external_id}</span></div>
-              <div><span className="text-muted-foreground">Confidence:</span> {Math.round(entity.confidence * 100)}%</div>
+              <div>
+                <span className="text-muted-foreground">{t("kg.entity.externalId")}</span>{" "}
+                <span className="font-mono">{entity.external_id}</span>
+              </div>
+              <div>
+                <span className="text-muted-foreground">{t("kg.entity.confidence")}</span>{" "}
+                {Math.round(entity.confidence * 100)}%
+              </div>
               {entity.description && (
-                <div className="col-span-2"><span className="text-muted-foreground">Description:</span> {entity.description}</div>
+                <div className="col-span-2">
+                  <span className="text-muted-foreground">{t("kg.entity.description")}</span>{" "}
+                  {entity.description}
+                </div>
               )}
               {entity.source_id && (
-                <div className="col-span-2"><span className="text-muted-foreground">Source:</span> <span className="font-mono">{entity.source_id}</span></div>
+                <div className="col-span-2">
+                  <span className="text-muted-foreground">{t("kg.entity.source")}</span>{" "}
+                  <span className="font-mono">{entity.source_id}</span>
+                </div>
               )}
               {entity.properties && Object.keys(entity.properties).length > 0 && (
                 <div className="col-span-2">
-                  <span className="text-muted-foreground">Properties:</span>
+                  <span className="text-muted-foreground">{t("kg.entity.properties")}</span>
                   <pre className="mt-1 text-xs bg-muted/50 rounded p-2 whitespace-pre-wrap">{JSON.stringify(entity.properties, null, 2)}</pre>
                 </div>
               )}
@@ -86,32 +100,34 @@ export function KGEntityDetailDialog({ open, onOpenChange, agentId, entity, getE
           {/* Relations */}
           <div>
             <div className="flex items-center justify-between mb-2">
-              <h4 className="text-sm font-medium">Relations</h4>
+              <h4 className="text-sm font-medium">{t("kg.entity.relations")}</h4>
               <Button variant="outline" size="sm" onClick={handleTraverse} disabled={traversing} className="gap-1">
                 <GitFork className="h-3.5 w-3.5" />
-                {traversing ? "Traversing..." : "Traverse (2-hop)"}
+                {traversing ? t("kg.entity.traversing") : t("kg.entity.traverse")}
               </Button>
             </div>
             {loadingRels ? (
-              <p className="text-xs text-muted-foreground">Loading...</p>
+              <p className="text-xs text-muted-foreground">{t("kg.entity.loading")}</p>
             ) : relations.length === 0 ? (
-              <p className="text-xs text-muted-foreground">No relations found.</p>
+              <p className="text-xs text-muted-foreground">{t("kg.entity.noRelations")}</p>
             ) : (
               <div className="rounded-md border">
                 <table className="w-full text-xs">
                   <thead>
                     <tr className="border-b bg-muted/50">
-                      <th className="px-3 py-2 text-left font-medium">Direction</th>
-                      <th className="px-3 py-2 text-left font-medium">Relation</th>
-                      <th className="px-3 py-2 text-left font-medium">Target</th>
-                      <th className="px-3 py-2 text-left font-medium">Confidence</th>
+                      <th className="px-3 py-2 text-left font-medium">{t("kg.entity.columns.direction")}</th>
+                      <th className="px-3 py-2 text-left font-medium">{t("kg.entity.columns.relation")}</th>
+                      <th className="px-3 py-2 text-left font-medium">{t("kg.entity.columns.target")}</th>
+                      <th className="px-3 py-2 text-left font-medium">{t("kg.entity.columns.confidence")}</th>
                     </tr>
                   </thead>
                   <tbody>
                     {relations.map((rel) => (
                       <tr key={rel.id} className="border-b last:border-0 hover:bg-muted/30">
                         <td className="px-3 py-2">
-                          {rel.source_entity_id === entity?.id ? "→ outgoing" : "← incoming"}
+                          {rel.source_entity_id === entity?.id
+                            ? t("kg.entity.direction.outgoing")
+                            : t("kg.entity.direction.incoming")}
                         </td>
                         <td className="px-3 py-2 font-mono">{rel.relation_type}</td>
                         <td className="px-3 py-2 font-mono text-muted-foreground">
@@ -129,7 +145,9 @@ export function KGEntityDetailDialog({ open, onOpenChange, agentId, entity, getE
           {/* Traversal results */}
           {traversalResults.length > 0 && (
             <div>
-              <h4 className="text-sm font-medium mb-2">Traversal Results ({traversalResults.length})</h4>
+              <h4 className="text-sm font-medium mb-2">
+                {t("kg.entity.traversalResults", { count: traversalResults.length })}
+              </h4>
               <div className="space-y-1">
                 {traversalResults.map((tr, i) => (
                   <div key={i} className="flex items-center gap-2 text-xs rounded border p-2">
diff --git a/ui/web/src/pages/memory/kg-extract-dialog.tsx b/ui/web/src/pages/memory/kg-extract-dialog.tsx
index 044b9009..fa9a1d35 100644
--- a/ui/web/src/pages/memory/kg-extract-dialog.tsx
+++ b/ui/web/src/pages/memory/kg-extract-dialog.tsx
@@ -8,6 +8,7 @@ import {
 } from "@/components/ui/dialog";
 import { Button } from "@/components/ui/button";
 import { Textarea } from "@/components/ui/textarea";
+import { useTranslation } from "react-i18next";
 import { ProviderModelSelect } from "@/components/shared/provider-model-select";
 
 interface KGExtractDialogProps {
@@ -17,6 +18,7 @@ interface KGExtractDialogProps {
 }
 
 export function KGExtractDialog({ open, onOpenChange, onExtract }: KGExtractDialogProps) {
+  const { t } = useTranslation("memory");
   const [text, setText] = useState("");
   const [provider, setProvider] = useState("");
   const [model, setModel] = useState("");
@@ -38,7 +40,7 @@ export function KGExtractDialog({ open, onOpenChange, onExtract }: KGExtractDial
     <Dialog open={open} onOpenChange={(v) => !loading && onOpenChange(v)}>
       <DialogContent className="max-w-2xl max-h-[85vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>Extract Entities from Text</DialogTitle>
+          <DialogTitle>{t("kg.extractDialog.title")}</DialogTitle>
         </DialogHeader>
 
         <div className="flex-1 min-h-0 overflow-y-auto py-2 px-1 -mx-1 space-y-4">
@@ -47,16 +49,16 @@ export function KGExtractDialog({ open, onOpenChange, onExtract }: KGExtractDial
             onProviderChange={setProvider}
             model={model}
             onModelChange={setModel}
-            providerLabel="Extraction Provider"
-            modelLabel="Extraction Model"
+            providerLabel={t("kg.extractDialog.providerLabel")}
+            modelLabel={t("kg.extractDialog.modelLabel")}
           />
 
           <div className="grid gap-1.5">
-            <label className="text-xs font-medium">Text to extract from</label>
+            <label className="text-xs font-medium">{t("kg.extractDialog.textLabel")}</label>
             <Textarea
               value={text}
               onChange={(e) => setText(e.target.value)}
-              placeholder="Paste conversation text, notes, or any content to extract entities and relations from..."
+              placeholder={t("kg.extractDialog.textPlaceholder")}
               rows={10}
             />
           </div>
@@ -64,10 +66,10 @@ export function KGExtractDialog({ open, onOpenChange, onExtract }: KGExtractDial
 
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>
-            Cancel
+            {t("kg.extractDialog.cancel")}
           </Button>
           <Button onClick={handleSubmit} disabled={loading || !text.trim() || !provider || !model}>
-            {loading ? "Extracting..." : "Extract"}
+            {loading ? t("kg.extractDialog.extracting") : t("kg.extractDialog.extract")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/memory/kg-graph-view.tsx b/ui/web/src/pages/memory/kg-graph-view.tsx
index 12087887..54001b8c 100644
--- a/ui/web/src/pages/memory/kg-graph-view.tsx
+++ b/ui/web/src/pages/memory/kg-graph-view.tsx
@@ -13,6 +13,7 @@ import {
 } from "@xyflow/react";
 import { forceSimulation, forceLink, forceManyBody, forceCenter, forceCollide, forceX, forceY, type SimulationNodeDatum } from "d3-force";
 import "@xyflow/react/dist/style.css";
+import { useTranslation } from "react-i18next";
 import type { KGEntity, KGRelation } from "@/types/knowledge-graph";
 
 // Color mapping for entity types
@@ -125,6 +126,7 @@ interface KGGraphViewProps {
 }
 
 export function KGGraphView({ entities, relations, onEntityClick }: KGGraphViewProps) {
+  const { t } = useTranslation("memory");
   const { nodes: initialNodes, edges: initialEdges } = useMemo(
     () => buildGraph(entities, relations),
     [entities, relations],
@@ -154,7 +156,7 @@ export function KGGraphView({ entities, relations, onEntityClick }: KGGraphViewP
   if (entities.length === 0) {
     return (
       <div className="flex items-center justify-center h-[400px] text-sm text-muted-foreground">
-        No entities to visualize
+        {t("kg.graphView.empty")}
       </div>
     );
   }
diff --git a/ui/web/src/pages/memory/memory-create-dialog.tsx b/ui/web/src/pages/memory/memory-create-dialog.tsx
index e55d5e93..724fcc22 100644
--- a/ui/web/src/pages/memory/memory-create-dialog.tsx
+++ b/ui/web/src/pages/memory/memory-create-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -26,6 +27,8 @@ interface MemoryCreateDialogProps {
 }
 
 export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId, knownUserIds = [] }: MemoryCreateDialogProps) {
+  const { t } = useTranslation("memory");
+  const { t: tc } = useTranslation("common");
   const { agents } = useAgents();
   const [selectedAgentId, setSelectedAgentId] = useState("");
   const [path, setPath] = useState("");
@@ -63,15 +66,15 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
 
   const handleSubmit = async () => {
     if (!effectiveAgentId) {
-      setError("Please select an agent");
+      setError(t("createDialog.agentRequired") ?? "Please select an agent");
       return;
     }
     if (!path.trim()) {
-      setError("Path is required");
+      setError(t("createDialog.pathRequired") ?? "Path is required");
       return;
     }
     if (!content.trim()) {
-      setError("Content is required");
+      setError(t("createDialog.contentRequired") ?? "Content is required");
       return;
     }
 
@@ -85,7 +88,7 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
       }
       onOpenChange(false);
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to create");
+      setError(err instanceof Error ? err.message : t("toast.failedCreate"));
     } finally {
       setLoading(false);
     }
@@ -95,20 +98,20 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
     <Dialog open={open} onOpenChange={(v) => !loading && onOpenChange(v)}>
       <DialogContent className="max-w-3xl max-h-[85vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>Create Memory Document</DialogTitle>
+          <DialogTitle>{t("createDialog.title")}</DialogTitle>
         </DialogHeader>
 
         <div className="grid gap-4 py-2 px-1 -mx-1 overflow-y-auto min-h-0">
           {/* Agent selector */}
           <div className="grid gap-1.5">
-            <Label htmlFor="mc-agent">Agent *</Label>
+            <Label htmlFor="mc-agent">{t("createDialog.agentId")}</Label>
             <select
               id="mc-agent"
               value={selectedAgentId || parentAgentId || ""}
               onChange={(e) => setSelectedAgentId(e.target.value)}
               className="h-9 rounded-md border bg-background px-3 text-sm"
             >
-              <option value="">Select agent...</option>
+              <option value="">{t("createDialog.agentIdPlaceholder")}</option>
               {agents.map((a) => (
                 <option key={a.id} value={a.id}>
                   {a.display_name || a.agent_key}
@@ -122,7 +125,7 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
 
           {/* Scope selector */}
           <div className="grid gap-1.5">
-            <Label>Scope</Label>
+            <Label>{t("createDialog.scope")}</Label>
             <div className="flex gap-2">
               <Button
                 type="button"
@@ -130,7 +133,7 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
                 size="sm"
                 onClick={() => setScopeMode("global")}
               >
-                Global
+                {t("scopeLabel.global")}
               </Button>
               {knownUserIds.length > 0 && (
                 <Button
@@ -139,7 +142,7 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
                   size="sm"
                   onClick={() => setScopeMode("existing")}
                 >
-                  Existing scope
+                  {t("createDialog.existingScope")}
                 </Button>
               )}
               <Button
@@ -148,7 +151,7 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
                 size="sm"
                 onClick={() => setScopeMode("custom")}
               >
-                Custom
+                {t("createDialog.customScope")}
               </Button>
             </div>
             {scopeMode === "existing" && knownUserIds.length > 0 && (
@@ -157,7 +160,7 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
                 onChange={(e) => setSelectedUserId(e.target.value)}
                 className="h-9 rounded-md border bg-background px-3 text-sm"
               >
-                <option value="">Select group/user...</option>
+                <option value="">{t("createDialog.selectGroupUser")}</option>
                 {knownUserIds.map((uid) => (
                   <option key={uid} value={uid}>
                     {formatScopeLabel(uid)}
@@ -174,30 +177,30 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
               />
             )}
             <p className="text-xs text-muted-foreground">
-              Global = shared across all users. Personal = scoped to a specific user or group chat.
+              {t("createDialog.scopeHint")}
             </p>
           </div>
 
           {/* Path */}
           <div className="grid gap-1.5">
-            <Label htmlFor="mc-path">Path *</Label>
+            <Label htmlFor="mc-path">{t("createDialog.path")}</Label>
             <Input
               id="mc-path"
               value={path}
               onChange={(e) => setPath(e.target.value)}
-              placeholder="e.g. notes/project-overview.md"
+              placeholder={t("createDialog.pathPlaceholder")}
               className="font-mono text-sm"
             />
           </div>
 
           {/* Content */}
           <div className="grid gap-1.5">
-            <Label htmlFor="mc-content">Content *</Label>
+            <Label htmlFor="mc-content">{t("createDialog.content")}</Label>
             <Textarea
               id="mc-content"
               value={content}
               onChange={(e) => setContent(e.target.value)}
-              placeholder="Document content..."
+              placeholder={t("createDialog.contentPlaceholder")}
               className="font-mono text-xs min-h-[200px]"
               rows={10}
             />
@@ -205,7 +208,7 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
 
           <div className="flex items-center gap-2">
             <Switch id="mc-index" checked={autoIndex} onCheckedChange={setAutoIndex} />
-            <Label htmlFor="mc-index">Auto-index after creation</Label>
+            <Label htmlFor="mc-index">{t("createDialog.autoIndex")}</Label>
           </div>
 
           {error && <p className="text-sm text-destructive">{error}</p>}
@@ -213,10 +216,10 @@ export function MemoryCreateDialog({ open, onOpenChange, agentId: parentAgentId,
 
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>
-            Cancel
+            {tc("cancel")}
           </Button>
           <Button onClick={handleSubmit} disabled={loading}>
-            {loading ? "Creating..." : "Create"}
+            {loading ? t("createDialog.creating") : t("createDialog.create")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/memory/memory-document-dialog.tsx b/ui/web/src/pages/memory/memory-document-dialog.tsx
index 295ddc95..b7528a9f 100644
--- a/ui/web/src/pages/memory/memory-document-dialog.tsx
+++ b/ui/web/src/pages/memory/memory-document-dialog.tsx
@@ -1,4 +1,6 @@
 import { useState, useEffect, useCallback } from "react";
+import { useTranslation } from "react-i18next";
+import i18next from "i18next";
 import {
   Dialog,
   DialogContent,
@@ -22,6 +24,8 @@ interface MemoryDocumentDialogProps {
 }
 
 export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }: MemoryDocumentDialogProps) {
+  const { t } = useTranslation("memory");
+  const { t: tc } = useTranslation("common");
   const http = useHttp();
   const [tab, setTab] = useState<"content" | "chunks">("content");
   const [detail, setDetail] = useState<MemoryDocumentDetail | null>(null);
@@ -44,7 +48,7 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
       setDetail(res);
       setContent(res.content);
     } catch {
-      toast.error("Failed to load document");
+      toast.error(i18next.t("memory:toast.failedCreate"));
     } finally {
       setLoadingDetail(false);
     }
@@ -91,10 +95,10 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
         content,
         user_id: document.user_id || "",
       });
-      toast.success("Document updated", document.path);
+      toast.success(i18next.t("memory:documentDialog.title"), document.path);
       onOpenChange(false);
     } catch (err) {
-      toast.error("Failed to save", err instanceof Error ? err.message : "Unknown error");
+      toast.error(i18next.t("memory:toast.failedCreate"), err instanceof Error ? err.message : "");
     } finally {
       setSaving(false);
     }
@@ -109,9 +113,9 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
           <DialogTitle className="flex items-center gap-2">
             <span className="font-mono text-sm">{document?.path}</span>
             {document?.user_id ? (
-              <Badge variant="secondary">Personal</Badge>
+              <Badge variant="secondary">{t("scopeLabel.personal")}</Badge>
             ) : (
-              <Badge variant="outline">Global</Badge>
+              <Badge variant="outline">{t("scopeLabel.global")}</Badge>
             )}
           </DialogTitle>
         </DialogHeader>
@@ -122,13 +126,13 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
             className={`px-4 py-2 text-sm font-medium border-b-2 -mb-px ${tab === "content" ? "border-primary text-primary" : "border-transparent text-muted-foreground hover:text-foreground"}`}
             onClick={() => setTab("content")}
           >
-            Content
+            {t("documentDialog.content")}
           </button>
           <button
             className={`px-4 py-2 text-sm font-medium border-b-2 -mb-px ${tab === "chunks" ? "border-primary text-primary" : "border-transparent text-muted-foreground hover:text-foreground"}`}
             onClick={() => setTab("chunks")}
           >
-            Chunks {detail && `(${detail.chunk_count})`}
+            {detail ? t("documentDialog.chunks", { count: detail.chunk_count }) : t("documentDialog.noChunks")}
           </button>
         </div>
 
@@ -137,15 +141,15 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
             <div className="grid gap-3">
               {detail && (
                 <div className="flex gap-4 text-xs text-muted-foreground">
-                  <span>Chunks: {detail.chunk_count}</span>
-                  <span>Embedded: {detail.embedded_count}/{detail.chunk_count}</span>
-                  <span>Created: {new Date(detail.created_at).toLocaleString()}</span>
+                  <span>{t("documentDialog.path")} {detail.chunk_count}</span>
+                  <span>{detail.embedded_count}/{detail.chunk_count}</span>
+                  <span>{new Date(detail.created_at).toLocaleString()}</span>
                 </div>
               )}
               <div className="grid gap-1.5">
-                <Label>Content</Label>
+                <Label>{t("documentDialog.content")}</Label>
                 {loadingDetail ? (
-                  <div className="h-48 flex items-center justify-center text-muted-foreground">Loading...</div>
+                  <div className="h-48 flex items-center justify-center text-muted-foreground">{tc("loading")}</div>
                 ) : (
                   <Textarea
                     value={content}
@@ -161,9 +165,9 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
           {tab === "chunks" && (
             <div>
               {loadingChunks ? (
-                <div className="py-8 text-center text-muted-foreground">Loading chunks...</div>
+                <div className="py-8 text-center text-muted-foreground">{tc("loading")}</div>
               ) : chunks.length === 0 ? (
-                <div className="py-8 text-center text-muted-foreground">No chunks. Index this document first.</div>
+                <div className="py-8 text-center text-muted-foreground">{t("documentDialog.noChunks")}</div>
               ) : (
                 <div className="space-y-2">
                   {chunks.map((chunk) => (
@@ -173,7 +177,7 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
                           Lines {chunk.start_line}-{chunk.end_line}
                         </span>
                         <Badge variant={chunk.has_embedding ? "default" : "secondary"} className="text-[10px]">
-                          {chunk.has_embedding ? "Embedded" : "No embedding"}
+                          {chunk.has_embedding ? t("documentDialog.embedded") : t("documentDialog.noEmbedding")}
                         </Badge>
                       </div>
                       <pre className="text-xs text-muted-foreground whitespace-pre-wrap break-words">
@@ -189,11 +193,11 @@ export function MemoryDocumentDialog({ open, onOpenChange, agentId, document }:
 
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={saving}>
-            Close
+            {tc("close")}
           </Button>
           {tab === "content" && (
             <Button onClick={handleSave} disabled={saving || !hasChanges}>
-              {saving ? "Saving..." : "Save"}
+              {saving ? tc("saving") : tc("save")}
             </Button>
           )}
         </DialogFooter>
diff --git a/ui/web/src/pages/memory/memory-page.tsx b/ui/web/src/pages/memory/memory-page.tsx
index ef214da3..9f65acaf 100644
--- a/ui/web/src/pages/memory/memory-page.tsx
+++ b/ui/web/src/pages/memory/memory-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useMemo } from "react";
+import { useTranslation } from "react-i18next";
 import { Brain, Plus, RefreshCw, Search, Database, Trash2, RotateCw, Network } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -19,6 +20,8 @@ import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 import type { MemoryDocument } from "@/types/memory";
 
 export function MemoryPage() {
+  const { t } = useTranslation("memory");
+  const { t: tc } = useTranslation("common");
   const { agents } = useAgents();
   const [agentId, setAgentId] = useState("");
   const [userIdFilter, setUserIdFilter] = useState("");
@@ -100,22 +103,22 @@ export function MemoryPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Memory"
-        description="Browse and manage agent memory documents, chunks, and embeddings"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex gap-2">
             {agentId && (
               <>
                 <Button size="sm" onClick={() => setSearchOpen(true)} className="gap-1" variant="outline">
-                  <Search className="h-3.5 w-3.5" /> Search
+                  <Search className="h-3.5 w-3.5" /> {t("search")}
                 </Button>
                 <Button size="sm" onClick={() => setCreateOpen(true)} className="gap-1">
-                  <Plus className="h-3.5 w-3.5" /> Create
+                  <Plus className="h-3.5 w-3.5" /> {t("create")}
                 </Button>
               </>
             )}
             <Button variant="outline" size="sm" onClick={() => refresh()} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
             </Button>
           </div>
         }
@@ -124,14 +127,14 @@ export function MemoryPage() {
       {/* Filters */}
       <div className="mt-4 flex flex-wrap items-end gap-3">
         <div className="grid gap-1.5">
-          <Label htmlFor="mem-agent" className="text-xs">Agent</Label>
+          <Label htmlFor="mem-agent" className="text-xs">{t("filters.agent")}</Label>
           <select
             id="mem-agent"
             value={agentId}
             onChange={(e) => { setAgentId(e.target.value); setUserIdFilter(""); setPage(1); }}
             className="h-9 rounded-md border bg-background px-3 text-sm"
           >
-            <option value="">All agents</option>
+            <option value="">{t("filters.allAgents")}</option>
             {agents.map((a) => (
               <option key={a.id} value={a.id}>
                 {a.display_name || a.agent_key}
@@ -140,14 +143,14 @@ export function MemoryPage() {
           </select>
         </div>
         <div className="grid gap-1.5">
-          <Label htmlFor="mem-scope" className="text-xs">Scope</Label>
+          <Label htmlFor="mem-scope" className="text-xs">{t("filters.scope")}</Label>
           <select
             id="mem-scope"
             value={userIdFilter}
             onChange={(e) => { setUserIdFilter(e.target.value); setPage(1); }}
             className="h-9 rounded-md border bg-background px-3 text-sm min-w-[180px]"
           >
-            <option value="">All (global + personal)</option>
+            <option value="">{t("filters.allScope")}</option>
             {userIds.map((uid) => (
               <option key={uid} value={uid}>
                 {formatScopeLabel(uid)}
@@ -164,7 +167,7 @@ export function MemoryPage() {
             className="h-9 gap-1"
           >
             <Database className="h-3.5 w-3.5" />
-            {indexAllLoading ? "Indexing..." : "Index All"}
+            {indexAllLoading ? t("indexing") : t("indexAll")}
           </Button>
         )}
       </div>
@@ -176,13 +179,13 @@ export function MemoryPage() {
             className={`px-4 py-2 text-sm font-medium border-b-2 -mb-px ${activeTab === "documents" ? "border-primary text-primary" : "border-transparent text-muted-foreground hover:text-foreground"}`}
             onClick={() => setActiveTab("documents")}
           >
-            <Brain className="inline h-3.5 w-3.5 mr-1.5" />Documents
+            <Brain className="inline h-3.5 w-3.5 mr-1.5" />{t("tabs.documents")}
           </button>
           <button
             className={`px-4 py-2 text-sm font-medium border-b-2 -mb-px ${activeTab === "kg" ? "border-primary text-primary" : "border-transparent text-muted-foreground hover:text-foreground"}`}
             onClick={() => setActiveTab("kg")}
           >
-            <Network className="inline h-3.5 w-3.5 mr-1.5" />Knowledge Graph
+            <Network className="inline h-3.5 w-3.5 mr-1.5" />{t("tabs.knowledgeGraph")}
           </button>
         </div>
       )}
@@ -201,20 +204,20 @@ export function MemoryPage() {
         ) : documents.length === 0 ? (
           <EmptyState
             icon={Brain}
-            title="No memory documents"
-            description={agentId ? "This agent has no memory documents yet." : "No memory documents found across any agent."}
+            title={t("emptyTitle")}
+            description={agentId ? t("emptyAgentDescription") : t("emptyGlobalDescription")}
           />
         ) : (
           <div className="rounded-md border">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Path</th>
-                  {!agentId && <th className="px-4 py-3 text-left font-medium">Agent</th>}
-                  <th className="px-4 py-3 text-left font-medium">Scope</th>
-                  <th className="px-4 py-3 text-left font-medium">Hash</th>
-                  <th className="px-4 py-3 text-left font-medium">Updated</th>
-                  <th className="px-4 py-3 text-right font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.path")}</th>
+                  {!agentId && <th className="px-4 py-3 text-left font-medium">{t("columns.agent")}</th>}
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.scope")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.hash")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.updated")}</th>
+                  <th className="px-4 py-3 text-right font-medium">{t("columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -241,7 +244,7 @@ export function MemoryPage() {
                     )}
                     <td className="px-4 py-3">
                       <Badge variant={doc.user_id ? "secondary" : "outline"}>
-                        {doc.user_id ? "Personal" : "Global"}
+                        {doc.user_id ? t("scopeLabel.personal") : t("scopeLabel.global")}
                       </Badge>
                       {doc.user_id && (
                         <span className="ml-1 text-xs text-muted-foreground">{formatScopeLabel(doc.user_id)}</span>
@@ -308,9 +311,9 @@ export function MemoryPage() {
       <ConfirmDialog
         open={!!deleteTarget}
         onOpenChange={(open) => !open && setDeleteTarget(null)}
-        title="Delete Memory Document"
-        description={`Are you sure you want to delete "${deleteTarget?.path}"? This will also delete all associated chunks and embeddings.`}
-        confirmLabel="Delete"
+        title={t("delete.title")}
+        description={t("delete.description", { path: deleteTarget?.path })}
+        confirmLabel={t("delete.confirmLabel")}
         variant="destructive"
         onConfirm={handleDelete}
         loading={deleteLoading}
diff --git a/ui/web/src/pages/memory/memory-search-dialog.tsx b/ui/web/src/pages/memory/memory-search-dialog.tsx
index f47b2046..fd97d4c9 100644
--- a/ui/web/src/pages/memory/memory-search-dialog.tsx
+++ b/ui/web/src/pages/memory/memory-search-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Search } from "lucide-react";
 import {
   Dialog,
@@ -18,6 +19,7 @@ interface MemorySearchDialogProps {
 }
 
 export function MemorySearchDialog({ open, onOpenChange, agentId }: MemorySearchDialogProps) {
+  const { t } = useTranslation("memory");
   const [query, setQuery] = useState("");
   const [userId, setUserId] = useState("");
   const { results, searching, search } = useMemorySearch(agentId);
@@ -37,7 +39,7 @@ export function MemorySearchDialog({ open, onOpenChange, agentId }: MemorySearch
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-w-2xl max-h-[85vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>Search Memory</DialogTitle>
+          <DialogTitle>{t("searchDialog.title")}</DialogTitle>
         </DialogHeader>
 
         <div className="flex gap-2">
@@ -46,7 +48,7 @@ export function MemorySearchDialog({ open, onOpenChange, agentId }: MemorySearch
               value={query}
               onChange={(e) => setQuery(e.target.value)}
               onKeyDown={handleKeyDown}
-              placeholder="Search query..."
+              placeholder={t("searchDialog.queryPlaceholder")}
               autoFocus
             />
           </div>
@@ -54,23 +56,23 @@ export function MemorySearchDialog({ open, onOpenChange, agentId }: MemorySearch
             <Input
               value={userId}
               onChange={(e) => setUserId(e.target.value)}
-              placeholder="User ID (opt.)"
+              placeholder={t("searchDialog.agentIdPlaceholder")}
             />
           </div>
           <Button onClick={handleSearch} disabled={searching || !query.trim()} className="gap-1">
             <Search className="h-3.5 w-3.5" />
-            {searching ? "..." : "Search"}
+            {searching ? "..." : t("searchDialog.search")}
           </Button>
         </div>
 
         <div className="flex-1 min-h-0 overflow-y-auto mt-2">
           {results.length === 0 ? (
             <div className="py-12 text-center text-muted-foreground text-sm">
-              {searching ? "Searching..." : "Enter a query and press Search."}
+              {searching ? t("searchDialog.searching") : t("searchDialog.noResults")}
             </div>
           ) : (
             <div className="space-y-2">
-              <p className="text-xs text-muted-foreground">{results.length} result(s)</p>
+              <p className="text-xs text-muted-foreground">{t("searchDialog.results")}: {results.length}</p>
               {results.map((r, i) => (
                 <div key={i} className="rounded-md border p-3">
                   <div className="flex items-center gap-2 mb-1">
diff --git a/ui/web/src/pages/nodes/nodes-page.tsx b/ui/web/src/pages/nodes/nodes-page.tsx
index c90bad4c..513918c8 100644
--- a/ui/web/src/pages/nodes/nodes-page.tsx
+++ b/ui/web/src/pages/nodes/nodes-page.tsx
@@ -1,5 +1,6 @@
 import { useState } from "react";
 import { Link as LinkIcon, RefreshCw, Check, X, Trash2 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { PageHeader } from "@/components/shared/page-header";
@@ -16,6 +17,7 @@ import { useMinLoading } from "@/hooks/use-min-loading";
 import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 
 export function NodesPage() {
+  const { t } = useTranslation("nodes");
   const { pendingPairings, pairedDevices, loading, refresh, approvePairing, denyPairing, revokePairing } = useNodes();
   const spinning = useMinLoading(loading);
   const isEmpty = pendingPairings.length === 0 && pairedDevices.length === 0;
@@ -27,11 +29,11 @@ export function NodesPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Nodes"
-        description="Manage paired devices and pending pairing requests"
+        title={t("title")}
+        description={t("description")}
         actions={
           <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("common:refresh", "Refresh")}
           </Button>
         }
       />
@@ -42,8 +44,8 @@ export function NodesPage() {
         ) : isEmpty ? (
           <EmptyState
             icon={LinkIcon}
-            title="No devices"
-            description="No paired devices or pending pairing requests."
+            title={t("emptyTitle")}
+            description={t("emptyDescription")}
           />
         ) : (
           <div className="space-y-6">
@@ -51,7 +53,7 @@ export function NodesPage() {
             {pendingPairings.length > 0 && (
               <div>
                 <h3 className="mb-3 text-sm font-medium">
-                  Pending Requests ({pendingPairings.length})
+                  {t("pendingRequests", { count: pendingPairings.length })}
                 </h3>
                 <div className="space-y-2">
                   {pendingPairings.map((p: PendingPairing) => (
@@ -62,8 +64,8 @@ export function NodesPage() {
                           <span className="font-mono text-sm font-medium">{p.code}</span>
                         </div>
                         <div className="mt-1 text-xs text-muted-foreground">
-                          Sender: {p.sender_id}
-                          {p.chat_id && ` | Chat: ${p.chat_id}`}
+                          {t("sender")}{p.sender_id}
+                          {p.chat_id && ` | ${t("chat")}${p.chat_id}`}
                           {" | "}
                           {formatRelativeTime(new Date(p.created_at))}
                         </div>
@@ -75,14 +77,14 @@ export function NodesPage() {
                           onClick={() => setDenyTarget(p)}
                           className="gap-1"
                         >
-                          <X className="h-3.5 w-3.5" /> Deny
+                          <X className="h-3.5 w-3.5" /> {t("deny")}
                         </Button>
                         <Button
                           size="sm"
                           onClick={() => setApproveTarget(p)}
                           className="gap-1"
                         >
-                          <Check className="h-3.5 w-3.5" /> Approve
+                          <Check className="h-3.5 w-3.5" /> {t("approve")}
                         </Button>
                       </div>
                     </div>
@@ -95,17 +97,17 @@ export function NodesPage() {
             {pairedDevices.length > 0 && (
               <div>
                 <h3 className="mb-3 text-sm font-medium">
-                  Paired Devices ({pairedDevices.length})
+                  {t("pairedDevices", { count: pairedDevices.length })}
                 </h3>
                 <div className="rounded-md border overflow-x-auto">
                   <table className="w-full min-w-[600px] text-sm">
                     <thead>
                       <tr className="border-b bg-muted/50">
-                        <th className="px-4 py-3 text-left font-medium">Channel</th>
-                        <th className="px-4 py-3 text-left font-medium">Sender ID</th>
-                        <th className="px-4 py-3 text-left font-medium">Paired</th>
-                        <th className="px-4 py-3 text-left font-medium">By</th>
-                        <th className="px-4 py-3 text-right font-medium">Actions</th>
+                        <th className="px-4 py-3 text-left font-medium">{t("columns.channel")}</th>
+                        <th className="px-4 py-3 text-left font-medium">{t("columns.senderId")}</th>
+                        <th className="px-4 py-3 text-left font-medium">{t("columns.paired")}</th>
+                        <th className="px-4 py-3 text-left font-medium">{t("columns.by")}</th>
+                        <th className="px-4 py-3 text-right font-medium">{t("columns.actions")}</th>
                       </tr>
                     </thead>
                     <tbody>
@@ -126,7 +128,7 @@ export function NodesPage() {
                               onClick={() => setRevokeTarget(d)}
                               className="gap-1"
                             >
-                              <Trash2 className="h-3.5 w-3.5" /> Revoke
+                              <Trash2 className="h-3.5 w-3.5" /> {t("revoke")}
                             </Button>
                           </td>
                         </tr>
@@ -144,9 +146,9 @@ export function NodesPage() {
         <ConfirmDialog
           open
           onOpenChange={() => setApproveTarget(null)}
-          title="Approve Pairing"
-          description={`Approve pairing request from ${approveTarget.channel}:${approveTarget.sender_id} (code: ${approveTarget.code})? This device will be able to interact with agents.`}
-          confirmLabel="Approve"
+          title={t("confirmApprove.title")}
+          description={t("confirmApprove.description", { channel: approveTarget.channel, senderId: approveTarget.sender_id, code: approveTarget.code })}
+          confirmLabel={t("confirmApprove.confirmLabel")}
           onConfirm={async () => {
             await approvePairing(approveTarget.code);
             setApproveTarget(null);
@@ -158,9 +160,9 @@ export function NodesPage() {
         <ConfirmDialog
           open
           onOpenChange={() => setDenyTarget(null)}
-          title="Deny Pairing"
-          description={`Deny pairing request from ${denyTarget.channel}:${denyTarget.sender_id} (code: ${denyTarget.code})? The request will be removed.`}
-          confirmLabel="Deny"
+          title={t("confirmDeny.title")}
+          description={t("confirmDeny.description", { channel: denyTarget.channel, senderId: denyTarget.sender_id, code: denyTarget.code })}
+          confirmLabel={t("confirmDeny.confirmLabel")}
           variant="destructive"
           onConfirm={async () => {
             await denyPairing(denyTarget.code);
@@ -173,9 +175,9 @@ export function NodesPage() {
         <ConfirmDialog
           open
           onOpenChange={() => setRevokeTarget(null)}
-          title="Revoke Device"
-          description={`Revoke pairing for ${revokeTarget.channel}:${revokeTarget.sender_id}? The device will need to re-pair.`}
-          confirmLabel="Revoke"
+          title={t("confirmRevoke.title")}
+          description={t("confirmRevoke.description", { channel: revokeTarget.channel, senderId: revokeTarget.sender_id })}
+          confirmLabel={t("confirmRevoke.confirmLabel")}
           variant="destructive"
           onConfirm={async () => {
             await revokePairing(revokeTarget.sender_id, revokeTarget.channel);
diff --git a/ui/web/src/pages/overview/connected-clients-card.tsx b/ui/web/src/pages/overview/connected-clients-card.tsx
index fe9297ca..d19b6bc4 100644
--- a/ui/web/src/pages/overview/connected-clients-card.tsx
+++ b/ui/web/src/pages/overview/connected-clients-card.tsx
@@ -1,4 +1,5 @@
 import { Users } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Badge } from "@/components/ui/badge";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import type { ClientInfo } from "./types";
@@ -11,11 +12,12 @@ export function ConnectedClientsCard({
   clients: ClientInfo[];
   currentId?: string;
 }) {
+  const { t } = useTranslation("overview");
   return (
     <Card>
       <CardHeader className="pb-3">
         <CardTitle className="text-base flex items-center gap-2">
-          <Users className="h-4 w-4" /> Connected Clients
+          <Users className="h-4 w-4" /> {t("connectedClients.title")}
           {clients.length > 0 && (
             <Badge variant="secondary" className="ml-1">
               {clients.length}
@@ -26,17 +28,17 @@ export function ConnectedClientsCard({
       <CardContent>
         {clients.length === 0 ? (
           <p className="py-6 text-center text-sm text-muted-foreground">
-            No clients connected
+            {t("connectedClients.noClients")}
           </p>
         ) : (
           <div className="overflow-x-auto">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b text-left text-muted-foreground">
-                  <th className="pb-2 pr-3 font-medium">IP</th>
-                  <th className="pb-2 px-3 font-medium">User</th>
-                  <th className="pb-2 px-3 font-medium">Role</th>
-                  <th className="pb-2 pl-3 font-medium">Connected</th>
+                  <th className="pb-2 pr-3 font-medium">{t("connectedClients.columns.ip")}</th>
+                  <th className="pb-2 px-3 font-medium">{t("connectedClients.columns.user")}</th>
+                  <th className="pb-2 px-3 font-medium">{t("connectedClients.columns.role")}</th>
+                  <th className="pb-2 pl-3 font-medium">{t("connectedClients.columns.connected")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -54,7 +56,7 @@ export function ConnectedClientsCard({
                             variant="info"
                             className="ml-1.5 text-[10px] px-1 py-0"
                           >
-                            you
+                            {t("connectedClients.you")}
                           </Badge>
                         )}
                       </td>
diff --git a/ui/web/src/pages/overview/cron-jobs-card.tsx b/ui/web/src/pages/overview/cron-jobs-card.tsx
index 72d031cb..1904a22f 100644
--- a/ui/web/src/pages/overview/cron-jobs-card.tsx
+++ b/ui/web/src/pages/overview/cron-jobs-card.tsx
@@ -1,28 +1,30 @@
 import { ArrowRight, Timer } from "lucide-react";
 import { Link } from "react-router";
+import { useTranslation } from "react-i18next";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { ROUTES } from "@/lib/constants";
 import { formatRelativeTime } from "@/lib/format";
 import type { CronJob } from "./types";
 
 export function CronJobsCard({ jobs }: { jobs: CronJob[] }) {
+  const { t } = useTranslation("overview");
   return (
     <Card>
       <CardHeader className="flex flex-row items-center justify-between pb-3">
-        <CardTitle className="text-base">Cron Jobs</CardTitle>
+        <CardTitle className="text-base">{t("cronJobs.title")}</CardTitle>
         {jobs.length > 0 && (
           <Link
             to={ROUTES.CRON}
             className="flex items-center gap-1 text-xs text-muted-foreground hover:text-foreground transition-colors"
           >
-            Manage <ArrowRight className="h-3 w-3" />
+            {t("cronJobs.manage")} <ArrowRight className="h-3 w-3" />
           </Link>
         )}
       </CardHeader>
       <CardContent>
         {jobs.length === 0 ? (
           <p className="py-6 text-center text-sm text-muted-foreground">
-            No cron jobs configured
+            {t("cronJobs.noJobs")}
           </p>
         ) : (
           <div className="space-y-2.5">
@@ -57,7 +59,7 @@ export function CronJobsCard({ jobs }: { jobs: CronJob[] }) {
                       ).replace(" ago", "")}
                     </>
                   ) : !job.enabled ? (
-                    "disabled"
+                    t("cronJobs.disabled")
                   ) : (
                     "--"
                   )}
diff --git a/ui/web/src/pages/overview/overview-page.tsx b/ui/web/src/pages/overview/overview-page.tsx
index 697a3736..753dc591 100644
--- a/ui/web/src/pages/overview/overview-page.tsx
+++ b/ui/web/src/pages/overview/overview-page.tsx
@@ -1,6 +1,7 @@
 import { useEffect, useCallback } from "react";
 import { Activity, Bot, Hash, Radio, AlertTriangle } from "lucide-react";
 import { Link } from "react-router";
+import { useTranslation } from "react-i18next";
 import { PageHeader } from "@/components/shared/page-header";
 import { StatusBadge } from "@/components/shared/status-badge";
 import { Alert, AlertTitle, AlertDescription } from "@/components/ui/alert";
@@ -31,6 +32,7 @@ import { QuotaUsageCard } from "./quota-usage-card";
 const REFRESH_INTERVAL = 30_000;
 
 export function OverviewPage() {
+  const { t } = useTranslation("overview");
   const connected = useAuthStore((s) => s.connected);
   const { call: fetchHealth, data: health } =
     useWsCall<HealthPayload>(Methods.HEALTH);
@@ -89,8 +91,8 @@ export function OverviewPage() {
     <div className="space-y-6 p-4 sm:p-6">
       {/* Header */}
       <PageHeader
-        title="Dashboard"
-        description="Gateway overview and quota usage"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex items-center gap-2">
             {health?.version && (
@@ -100,7 +102,7 @@ export function OverviewPage() {
             )}
             <StatusBadge
               status={connected ? "success" : "error"}
-              label={connected ? "Connected" : "Disconnected"}
+              label={connected ? t("common:connected", "Connected") : t("common:disconnected", "Disconnected")}
             />
           </div>
         }
@@ -112,18 +114,18 @@ export function OverviewPage() {
           <AlertTriangle className="h-4 w-4" />
           <AlertTitle>
             {hasNoProviders
-              ? "No LLM providers configured"
-              : "No LLM providers enabled"}
+              ? t("providers.noProvidersTitle")
+              : t("providers.noEnabledTitle")}
           </AlertTitle>
           <AlertDescription>
             {hasNoProviders
-              ? "You need to add at least one LLM provider before agents can work. "
-              : "All providers are currently disabled. Enable at least one to start using agents. "}
+              ? t("providers.noProvidersDesc")
+              : t("providers.noEnabledDesc")}
             <Link
               to={ROUTES.PROVIDERS}
               className="font-medium underline underline-offset-4 hover:text-foreground"
             >
-              Go to Provider Settings
+              {t("providers.goToSettings")}
             </Link>
           </AlertDescription>
         </Alert>
@@ -133,45 +135,45 @@ export function OverviewPage() {
       <div className="grid gap-4 sm:grid-cols-2 lg:grid-cols-4">
         <StatCard
           icon={Activity}
-          label="Requests Today"
+          label={t("statCards.requestsToday")}
           value={quota?.requestsToday ?? 0}
           sub={
             quota?.uniqueUsersToday
-              ? `${quota.uniqueUsersToday} users`
+              ? t("statCards.users", { count: quota.uniqueUsersToday })
               : undefined
           }
         />
         <StatCard
           icon={Hash}
-          label="Tokens Today"
+          label={t("statCards.tokensToday")}
           value={formatTokens(
             (quota?.inputTokensToday ?? 0) + (quota?.outputTokensToday ?? 0),
           )}
           sub={
             quota
-              ? `${formatTokens(quota.inputTokensToday)} in / ${formatTokens(quota.outputTokensToday)} out`
+              ? t("statCards.inOut", { input: formatTokens(quota.inputTokensToday), output: formatTokens(quota.outputTokensToday) })
               : undefined
           }
         />
         <StatCard
           icon={Bot}
-          label="Agents"
+          label={t("statCards.agents")}
           value={
             agentTotal > 0
               ? `${runningAgents} / ${agentTotal}`
               : "0"
           }
-          sub={agentTotal > 0 ? "running" : undefined}
+          sub={agentTotal > 0 ? t("statCards.running") : undefined}
         />
         <StatCard
           icon={Radio}
-          label="Channels"
+          label={t("statCards.channels")}
           value={
             channelEntries.length > 0
               ? `${channelsOnline} / ${channelEntries.length}`
               : "0"
           }
-          sub={channelEntries.length > 0 ? "online" : undefined}
+          sub={channelEntries.length > 0 ? t("statCards.online") : undefined}
         />
       </div>
 
diff --git a/ui/web/src/pages/overview/quota-usage-card.tsx b/ui/web/src/pages/overview/quota-usage-card.tsx
index ed9e6521..60bbadf8 100644
--- a/ui/web/src/pages/overview/quota-usage-card.tsx
+++ b/ui/web/src/pages/overview/quota-usage-card.tsx
@@ -1,10 +1,12 @@
+import { useTranslation } from "react-i18next";
 import { StatusBadge } from "@/components/shared/status-badge";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import type { QuotaUsage, QuotaUsageResult } from "./types";
 
 function QuotaBar({ used, limit }: { used: number; limit: number }) {
+  const { t } = useTranslation("overview");
   if (limit === 0) {
-    return <span className="text-xs text-muted-foreground">no limit</span>;
+    return <span className="text-xs text-muted-foreground">{t("quotaUsage.noLimit")}</span>;
   }
   const pct = Math.min((used / limit) * 100, 100);
   const color =
@@ -37,21 +39,22 @@ function QuotaCell({ usage }: { usage: QuotaUsage }) {
 }
 
 export function QuotaUsageCard({ quota }: { quota: QuotaUsageResult }) {
+  const { t } = useTranslation("overview");
   return (
     <Card>
       <CardHeader className="flex flex-row items-center justify-between pb-3">
-        <CardTitle className="text-base">Quota Usage</CardTitle>
-        <StatusBadge status="success" label="Enabled" />
+        <CardTitle className="text-base">{t("quotaUsage.title")}</CardTitle>
+        <StatusBadge status="success" label={t("common:enabled", "Enabled")} />
       </CardHeader>
       <CardContent>
         <div className="overflow-x-auto">
           <table className="w-full text-sm">
             <thead>
               <tr className="border-b text-left text-muted-foreground">
-                <th className="pb-2 pr-4 font-medium">User / Group</th>
-                <th className="pb-2 px-4 font-medium w-36">Hour</th>
-                <th className="pb-2 px-4 font-medium w-36">Day</th>
-                <th className="pb-2 pl-4 font-medium w-36">Week</th>
+                <th className="pb-2 pr-4 font-medium">{t("quotaUsage.columns.userGroup")}</th>
+                <th className="pb-2 px-4 font-medium w-36">{t("quotaUsage.columns.hour")}</th>
+                <th className="pb-2 px-4 font-medium w-36">{t("quotaUsage.columns.day")}</th>
+                <th className="pb-2 pl-4 font-medium w-36">{t("quotaUsage.columns.week")}</th>
               </tr>
             </thead>
             <tbody>
diff --git a/ui/web/src/pages/overview/recent-requests-card.tsx b/ui/web/src/pages/overview/recent-requests-card.tsx
index cf489359..00d096c1 100644
--- a/ui/web/src/pages/overview/recent-requests-card.tsx
+++ b/ui/web/src/pages/overview/recent-requests-card.tsx
@@ -1,5 +1,6 @@
 import { ArrowRight } from "lucide-react";
 import { Link } from "react-router";
+import { useTranslation } from "react-i18next";
 import { StatusBadge } from "@/components/shared/status-badge";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { ROUTES } from "@/lib/constants";
@@ -22,38 +23,39 @@ interface Trace {
 }
 
 export function RecentRequestsCard({ traces }: { traces: Trace[] }) {
+  const { t } = useTranslation("overview");
   return (
     <Card>
       <CardHeader className="flex flex-row items-center justify-between pb-3">
-        <CardTitle className="text-base">Recent Requests</CardTitle>
+        <CardTitle className="text-base">{t("recentRequests.title")}</CardTitle>
         {traces.length > 0 && (
           <Link
             to={ROUTES.TRACES}
             className="flex items-center gap-1 text-xs text-muted-foreground hover:text-foreground transition-colors"
           >
-            View All <ArrowRight className="h-3 w-3" />
+            {t("recentRequests.viewAll")} <ArrowRight className="h-3 w-3" />
           </Link>
         )}
       </CardHeader>
       <CardContent>
         {traces.length === 0 ? (
           <p className="py-6 text-center text-sm text-muted-foreground">
-            No recent requests
+            {t("recentRequests.noRequests")}
           </p>
         ) : (
           <div className="overflow-x-auto">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b text-left text-muted-foreground">
-                  <th className="pb-2 pr-4 font-medium">Time</th>
-                  <th className="pb-2 px-4 font-medium">Name</th>
-                  <th className="pb-2 px-4 font-medium">User</th>
-                  <th className="pb-2 px-4 font-medium">Channel</th>
-                  <th className="pb-2 px-4 font-medium text-right">Tokens</th>
+                  <th className="pb-2 pr-4 font-medium">{t("recentRequests.columns.time")}</th>
+                  <th className="pb-2 px-4 font-medium">{t("recentRequests.columns.name")}</th>
+                  <th className="pb-2 px-4 font-medium">{t("recentRequests.columns.user")}</th>
+                  <th className="pb-2 px-4 font-medium">{t("recentRequests.columns.channel")}</th>
+                  <th className="pb-2 px-4 font-medium text-right">{t("recentRequests.columns.tokens")}</th>
                   <th className="pb-2 px-4 font-medium text-right">
-                    Duration
+                    {t("recentRequests.columns.duration")}
                   </th>
-                  <th className="pb-2 pl-4 font-medium">Status</th>
+                  <th className="pb-2 pl-4 font-medium">{t("recentRequests.columns.status")}</th>
                 </tr>
               </thead>
               <tbody>
diff --git a/ui/web/src/pages/overview/system-health-card.tsx b/ui/web/src/pages/overview/system-health-card.tsx
index e888d654..7fee95f5 100644
--- a/ui/web/src/pages/overview/system-health-card.tsx
+++ b/ui/web/src/pages/overview/system-health-card.tsx
@@ -9,6 +9,7 @@ import {
   XCircle,
   Minus,
 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import type { HealthPayload, ChannelStatusEntry } from "./types";
 import { formatUptime } from "./hooks/use-live-uptime";
@@ -65,54 +66,55 @@ export function SystemHealthCard({
   clientCount: number;
   channelEntries: [string, ChannelStatusEntry][];
 }) {
+  const { t } = useTranslation("overview");
   return (
     <Card className="gap-4">
       <CardHeader>
         <CardTitle className="text-base flex items-center gap-2">
-          <Monitor className="h-4 w-4" /> System Health
+          <Monitor className="h-4 w-4" /> {t("systemHealth.title")}
         </CardTitle>
       </CardHeader>
       <CardContent className="space-y-4">
         <div className="grid gap-3 sm:grid-cols-2 lg:grid-cols-3">
           <HealthCell
-            label="Uptime"
+            label={t("systemHealth.uptime")}
             icon={Timer}
             value={formatUptime(liveUptime)}
           />
           {health?.database && (
             <HealthCell
-              label="Database"
+              label={t("systemHealth.database")}
               icon={Database}
               value={
                 health.database === "ok"
-                  ? "Connected"
+                  ? t("common:connected", "Connected")
                   : health.database
               }
               statusOk={health.database === "ok"}
             />
           )}
           <HealthCell
-            label="Providers"
+            label={t("systemHealth.providers")}
             icon={Radio}
             value={
               enabledProviderCount > 0
-                ? `${enabledProviderCount} active`
-                : "none"
+                ? t("systemHealth.active", { count: enabledProviderCount })
+                : t("systemHealth.none")
             }
             statusOk={enabledProviderCount > 0}
           />
           <HealthCell
-            label="Tools"
+            label={t("systemHealth.tools")}
             icon={Wrench}
             value={String(health?.tools ?? 0)}
           />
           <HealthCell
-            label="Sessions"
+            label={t("systemHealth.sessions")}
             icon={Monitor}
             value={String(sessions)}
           />
           <HealthCell
-            label="Clients"
+            label={t("systemHealth.clients")}
             icon={Users}
             value={String(clientCount)}
           />
@@ -121,7 +123,7 @@ export function SystemHealthCard({
         {channelEntries.length > 0 && (
           <div className="border-t pt-4">
             <p className="mb-2 text-xs font-medium text-muted-foreground uppercase tracking-wider">
-              Channels
+              {t("systemHealth.channels")}
             </p>
             <div className="flex flex-wrap gap-1.5">
               {channelEntries.map(([name, ch]) => (
diff --git a/ui/web/src/pages/pending-messages/message-list-dialog.tsx b/ui/web/src/pages/pending-messages/message-list-dialog.tsx
index 35df9768..597147b1 100644
--- a/ui/web/src/pages/pending-messages/message-list-dialog.tsx
+++ b/ui/web/src/pages/pending-messages/message-list-dialog.tsx
@@ -1,4 +1,5 @@
 import { useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -24,6 +25,7 @@ export function MessageListDialog({
   onClose,
   onLoad,
 }: MessageListDialogProps) {
+  const { t } = useTranslation("pending-messages");
   useEffect(() => {
     onLoad(group.channel_name, group.history_key);
   }, [group.channel_name, group.history_key, onLoad]);
@@ -33,7 +35,7 @@ export function MessageListDialog({
       <DialogContent className="max-h-[85vh] overflow-y-auto sm:max-w-2xl">
         <DialogHeader>
           <DialogTitle className="flex items-center gap-2 truncate">
-            Messages — {group.group_title || group.history_key}
+            {t("dialog.title", { name: group.group_title || group.history_key })}
             <Badge variant="outline" className="text-xs">{group.channel_name}</Badge>
           </DialogTitle>
         </DialogHeader>
@@ -43,7 +45,7 @@ export function MessageListDialog({
             <div className="h-6 w-6 animate-spin rounded-full border-2 border-muted-foreground border-t-transparent" />
           </div>
         ) : messages.length === 0 ? (
-          <p className="py-8 text-center text-sm text-muted-foreground">No messages found.</p>
+          <p className="py-8 text-center text-sm text-muted-foreground">{t("dialog.noMessages")}</p>
         ) : (
           <div className="space-y-3">
             {messages.map((msg) => (
@@ -58,7 +60,7 @@ export function MessageListDialog({
                   <span className="font-medium">{msg.sender}</span>
                   <span className="text-xs text-muted-foreground">({msg.sender_id})</span>
                   {msg.is_summary && (
-                    <Badge variant="warning" className="text-xs">Summary</Badge>
+                    <Badge variant="warning" className="text-xs">{t("dialog.summary")}</Badge>
                   )}
                   <span className="ml-auto text-xs text-muted-foreground">
                     {formatDate(msg.created_at)}
diff --git a/ui/web/src/pages/pending-messages/pending-messages-page.tsx b/ui/web/src/pages/pending-messages/pending-messages-page.tsx
index 537f059c..cc89ef20 100644
--- a/ui/web/src/pages/pending-messages/pending-messages-page.tsx
+++ b/ui/web/src/pages/pending-messages/pending-messages-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Inbox, RefreshCw, Trash2, Archive } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -13,6 +14,8 @@ import { MessageListDialog } from "./message-list-dialog";
 import type { PendingMessageGroup } from "./types";
 
 export function PendingMessagesPage() {
+  const { t } = useTranslation("pending-messages");
+  const { t: tc } = useTranslation("common");
   const {
     groups,
     messages,
@@ -57,11 +60,11 @@ export function PendingMessagesPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Pending Messages"
-        description="Buffered channel messages awaiting agent processing"
+        title={t("title")}
+        description={t("description")}
         actions={
           <Button variant="outline" size="sm" onClick={handleRefresh} disabled={spinning} className="gap-1">
-            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
           </Button>
         }
       />
@@ -72,20 +75,20 @@ export function PendingMessagesPage() {
         ) : groups.length === 0 ? (
           <EmptyState
             icon={Inbox}
-            title="No pending messages"
-            description="No buffered message groups found. Messages appear here when channels buffer incoming messages before agent processing."
+            title={t("emptyTitle")}
+            description={t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Channel</th>
-                  <th className="px-4 py-3 text-left font-medium">Group</th>
-                  <th className="px-4 py-3 text-left font-medium">Messages</th>
-                  <th className="px-4 py-3 text-left font-medium">Status</th>
-                  <th className="px-4 py-3 text-left font-medium">Last Activity</th>
-                  <th className="px-4 py-3 text-left font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.channel")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.group")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.messages")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.status")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.lastActivity")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -109,9 +112,9 @@ export function PendingMessagesPage() {
                       <td className="px-4 py-3">{g.message_count}</td>
                       <td className="px-4 py-3">
                         {g.has_summary ? (
-                          <Badge variant="success" className="text-xs">Compacted</Badge>
+                          <Badge variant="success" className="text-xs">{t("status.compacted")}</Badge>
                         ) : (
-                          <Badge variant="secondary" className="text-xs">Raw</Badge>
+                          <Badge variant="secondary" className="text-xs">{t("status.raw")}</Badge>
                         )}
                       </td>
                       <td className="px-4 py-3 text-muted-foreground">
@@ -126,7 +129,7 @@ export function PendingMessagesPage() {
                             disabled={busy || g.has_summary}
                             onClick={(e) => handleCompact(e, g)}
                           >
-                            <Archive className="h-3 w-3" /> Compact
+                            <Archive className="h-3 w-3" /> {t("compact")}
                           </Button>
                           <Button
                             variant="outline"
@@ -135,7 +138,7 @@ export function PendingMessagesPage() {
                             disabled={busy}
                             onClick={(e) => { e.stopPropagation(); setConfirmClear(g); }}
                           >
-                            <Trash2 className="h-3 w-3" /> Clear
+                            <Trash2 className="h-3 w-3" /> {t("clear")}
                           </Button>
                         </div>
                       </td>
@@ -178,18 +181,18 @@ function ConfirmClearDialog({
   onConfirm: () => void;
   onCancel: () => void;
 }) {
+  const { t } = useTranslation("pending-messages");
+  const { t: tc } = useTranslation("common");
   return (
     <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50">
       <div className="w-full max-w-sm rounded-lg border bg-background p-6 shadow-lg">
-        <h3 className="mb-2 font-semibold">Clear messages?</h3>
+        <h3 className="mb-2 font-semibold">{t("confirmClear.title")}</h3>
         <p className="mb-4 text-sm text-muted-foreground">
-          This will permanently delete all messages in{" "}
-          <span className="font-mono text-xs">{group.channel_name} / {group.history_key}</span>.
-          This action cannot be undone.
+          {t("confirmClear.description", { channel: group.channel_name, key: group.history_key })}
         </p>
         <div className="flex justify-end gap-2">
-          <Button variant="outline" size="sm" onClick={onCancel}>Cancel</Button>
-          <Button variant="destructive" size="sm" onClick={onConfirm}>Clear</Button>
+          <Button variant="outline" size="sm" onClick={onCancel}>{tc("cancel")}</Button>
+          <Button variant="destructive" size="sm" onClick={onConfirm}>{t("confirmClear.confirm")}</Button>
         </div>
       </div>
     </div>
diff --git a/ui/web/src/pages/providers/hooks/use-providers.ts b/ui/web/src/pages/providers/hooks/use-providers.ts
index 592f6a2d..d116bba4 100644
--- a/ui/web/src/pages/providers/hooks/use-providers.ts
+++ b/ui/web/src/pages/providers/hooks/use-providers.ts
@@ -1,5 +1,6 @@
 import { useCallback } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
+import i18next from "i18next";
 import { useHttp } from "@/hooks/use-ws";
 import { queryKeys } from "@/lib/query-keys";
 import { toast } from "@/stores/use-toast-store";
@@ -30,10 +31,13 @@ export function useProviders() {
       try {
         const res = await http.post<ProviderData>("/v1/providers", data);
         await invalidate();
-        toast.success("Provider created", `${data.name} has been added`);
+        toast.success(
+          i18next.t("providers:toast.created"),
+          i18next.t("providers:toast.createdDesc", { name: data.name }),
+        );
         return res;
       } catch (err) {
-        toast.error("Failed to create provider", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("providers:toast.failedCreate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -45,9 +49,9 @@ export function useProviders() {
       try {
         await http.put(`/v1/providers/${id}`, data);
         await invalidate();
-        toast.success("Provider updated");
+        toast.success(i18next.t("providers:toast.updated"));
       } catch (err) {
-        toast.error("Failed to update provider", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("providers:toast.failedUpdate"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
@@ -59,9 +63,9 @@ export function useProviders() {
       try {
         await http.delete(`/v1/providers/${id}`);
         await invalidate();
-        toast.success("Provider deleted");
+        toast.success(i18next.t("providers:toast.deleted"));
       } catch (err) {
-        toast.error("Failed to delete provider", err instanceof Error ? err.message : "Unknown error");
+        toast.error(i18next.t("providers:toast.failedDelete"), err instanceof Error ? err.message : "");
         throw err;
       }
     },
diff --git a/ui/web/src/pages/providers/provider-cli-section.tsx b/ui/web/src/pages/providers/provider-cli-section.tsx
index dd0e60a3..7444968c 100644
--- a/ui/web/src/pages/providers/provider-cli-section.tsx
+++ b/ui/web/src/pages/providers/provider-cli-section.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Loader2, CheckCircle2, AlertTriangle, RefreshCw } from "lucide-react";
 import { useHttp } from "@/hooks/use-ws";
@@ -11,6 +12,7 @@ interface CLIAuthStatus {
 }
 
 export function CLISection({ open }: { open: boolean }) {
+  const { t } = useTranslation("providers");
   const http = useHttp();
   const [cliAuth, setCliAuth] = useState<CLIAuthStatus | null>(null);
   const [loading, setLoading] = useState(false);
@@ -35,12 +37,12 @@ export function CLISection({ open }: { open: boolean }) {
   return (
     <div className="space-y-3">
       <p className="text-sm text-muted-foreground">
-        Claude CLI uses your local <code className="rounded bg-muted px-1 py-0.5">claude</code> binary. No API key needed.
+        {t("cli.description")} <code className="rounded bg-muted px-1 py-0.5">claude</code> {t("cli.descriptionSuffix")}
       </p>
       {loading ? (
         <div className="flex items-center gap-2 text-sm text-muted-foreground">
           <Loader2 className="h-3.5 w-3.5 animate-spin" />
-          Checking authentication...
+          {t("cli.checkingAuth")}
         </div>
       ) : cliAuth?.logged_in ? (
         <div className="space-y-2">
@@ -48,7 +50,7 @@ export function CLISection({ open }: { open: boolean }) {
             <div className="flex items-center gap-2">
               <CheckCircle2 className="h-4 w-4 text-green-600 dark:text-green-400" />
               <p className="text-sm text-green-700 dark:text-green-300">
-                Authenticated as <strong>{cliAuth.email}</strong>
+                {t("cli.authenticatedAs")} <strong>{cliAuth.email}</strong>
                 {cliAuth.subscription_type && (
                   <span className="ml-1 text-xs opacity-75">({cliAuth.subscription_type})</span>
                 )}
@@ -65,11 +67,11 @@ export function CLISection({ open }: { open: boolean }) {
             </Button>
           </div>
           <details className="text-xs text-muted-foreground">
-            <summary className="cursor-pointer hover:text-foreground">Switch account?</summary>
+            <summary className="cursor-pointer hover:text-foreground">{t("cli.switchAccount")}</summary>
             <div className="mt-1.5 space-y-1 rounded-md border bg-muted/50 px-3 py-2">
-              <p>Run on the server terminal:</p>
+              <p>{t("cli.switchAccountInstructions")}</p>
               <code className="block rounded bg-muted px-2 py-1 font-mono">claude auth logout && claude auth login</code>
-              <p>Then click <RefreshCw className="inline h-3 w-3" /> to re-check.</p>
+              <p>{t("cli.switchAccountRecheck")} <RefreshCw className="inline h-3 w-3" /> {t("cli.switchAccountRecheckSuffix")}</p>
             </div>
           </details>
         </div>
@@ -78,7 +80,7 @@ export function CLISection({ open }: { open: boolean }) {
           <div className="flex items-center justify-between">
             <div className="flex items-center gap-2">
               <AlertTriangle className="h-4 w-4 text-amber-600 dark:text-amber-400" />
-              <p className="text-sm font-medium text-amber-700 dark:text-amber-300">Not authenticated</p>
+              <p className="text-sm font-medium text-amber-700 dark:text-amber-300">{t("cli.notAuthenticated")}</p>
             </div>
             <Button
               type="button"
@@ -88,11 +90,11 @@ export function CLISection({ open }: { open: boolean }) {
               onClick={checkAuth}
             >
               <RefreshCw className="h-3.5 w-3.5 mr-1" />
-              <span className="text-xs">Re-check</span>
+              <span className="text-xs">{t("cli.recheckButton")}</span>
             </Button>
           </div>
           <p className="mt-1 text-sm text-amber-600 dark:text-amber-400">
-            Run on the server terminal:
+            {t("cli.runOnServer")}
           </p>
           <code className="mt-1 block rounded bg-amber-100 px-2 py-1 text-xs font-mono dark:bg-amber-900 dark:text-amber-300">
             claude auth login
diff --git a/ui/web/src/pages/providers/provider-form-dialog.tsx b/ui/web/src/pages/providers/provider-form-dialog.tsx
index 05117854..d9207468 100644
--- a/ui/web/src/pages/providers/provider-form-dialog.tsx
+++ b/ui/web/src/pages/providers/provider-form-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { useQueryClient } from "@tanstack/react-query";
 import {
   Dialog,
@@ -34,6 +35,7 @@ interface ProviderFormDialogProps {
 }
 
 export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, existingProviders = [] }: ProviderFormDialogProps) {
+  const { t } = useTranslation("providers");
   const isEdit = !!provider;
   const queryClient = useQueryClient();
   const [name, setName] = useState("");
@@ -92,7 +94,7 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
       await onSubmit(data);
       onOpenChange(false);
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to save provider");
+      setError(err instanceof Error ? err.message : t("form.saving"));
     } finally {
       setLoading(false);
     }
@@ -102,8 +104,8 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-h-[85vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>{isEdit ? "Edit Provider" : "Add Provider"}</DialogTitle>
-          <DialogDescription>Configure an LLM provider connection.</DialogDescription>
+          <DialogTitle>{isEdit ? t("form.editTitle") : t("form.createTitle")}</DialogTitle>
+          <DialogDescription>{t("form.configure")}</DialogDescription>
         </DialogHeader>
         <div className="space-y-4 py-4 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
           {/* Provider type selector — always shown in create mode */}
@@ -111,9 +113,11 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
             <ProviderTypeSelect
               value={providerType}
               hasClaudeCLI={hasClaudeCLI}
+              alreadyAddedLabel={t("form.alreadyAdded")}
+              providerTypeLabel={t("form.providerType")}
               onChange={(v) => {
                 setProviderType(v);
-                const preset = PROVIDER_TYPES.find((t) => t.value === v);
+                const preset = PROVIDER_TYPES.find((pt) => pt.value === v);
                 setApiBase(preset?.apiBase || "");
                 if (v === "chatgpt_oauth") {
                   setName("openai-codex");
@@ -130,11 +134,11 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
             <>
               <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
                 <div className="space-y-2">
-                  <Label>Name</Label>
+                  <Label>{t("form.nameFixed")}</Label>
                   <Input value="openai-codex" disabled />
                 </div>
                 <div className="space-y-2">
-                  <Label>Display Name</Label>
+                  <Label>{t("form.displayName")}</Label>
                   <Input value="ChatGPT (OAuth)" disabled />
                 </div>
               </div>
@@ -144,38 +148,38 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
             <>
               <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
                 <div className="space-y-2">
-                  <Label htmlFor="name">Name *</Label>
+                  <Label htmlFor="name">{t("form.name")}</Label>
                   <Input
                     id="name"
                     value={name}
                     onChange={(e) => setName(slugify(e.target.value))}
-                    placeholder="e.g. openrouter"
+                    placeholder={t("form.namePlaceholder")}
                     disabled={isEdit}
                   />
-                  <p className="text-xs text-muted-foreground">Lowercase, numbers, hyphens</p>
+                  <p className="text-xs text-muted-foreground">{t("form.nameHint")}</p>
                 </div>
                 <div className="space-y-2">
-                  <Label htmlFor="displayName">Display Name</Label>
+                  <Label htmlFor="displayName">{t("form.displayName")}</Label>
                   <Input
                     id="displayName"
                     value={displayName}
                     onChange={(e) => setDisplayName(e.target.value)}
-                    placeholder="OpenRouter"
+                    placeholder={t("form.displayNamePlaceholder")}
                   />
                 </div>
               </div>
 
               {isEdit && (
                 <div className="space-y-2">
-                  <Label>Provider Type *</Label>
+                  <Label>{t("form.providerType")}</Label>
                   <Select value={providerType} onValueChange={setProviderType}>
                     <SelectTrigger>
                       <SelectValue />
                     </SelectTrigger>
                     <SelectContent>
-                      {PROVIDER_TYPES.filter((t) => t.value !== "chatgpt_oauth").map((t) => (
-                        <SelectItem key={t.value} value={t.value}>
-                          {t.label}
+                      {PROVIDER_TYPES.filter((pt) => pt.value !== "chatgpt_oauth").map((pt) => (
+                        <SelectItem key={pt.value} value={pt.value}>
+                          {pt.label}
                         </SelectItem>
                       ))}
                     </SelectContent>
@@ -190,27 +194,27 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
               {!isCLI && (
                 <>
                   <div className="space-y-2">
-                    <Label htmlFor="apiBase">API Base URL</Label>
+                    <Label htmlFor="apiBase">{t("form.apiBase")}</Label>
                     <Input
                       id="apiBase"
                       value={apiBase}
                       onChange={(e) => setApiBase(e.target.value)}
-                      placeholder={PROVIDER_TYPES.find((t) => t.value === providerType)?.placeholder || PROVIDER_TYPES.find((t) => t.value === providerType)?.apiBase || "https://api.example.com/v1"}
+                      placeholder={PROVIDER_TYPES.find((pt) => pt.value === providerType)?.placeholder || PROVIDER_TYPES.find((pt) => pt.value === providerType)?.apiBase || "https://api.example.com/v1"}
                     />
                   </div>
 
                   <div className="space-y-2">
-                    <Label htmlFor="apiKey">API Key</Label>
+                    <Label htmlFor="apiKey">{t("form.apiKey")}</Label>
                     <Input
                       id="apiKey"
                       type="password"
                       value={apiKey}
                       onChange={(e) => setApiKey(e.target.value)}
-                      placeholder={isEdit ? "Leave as-is or enter new key" : "sk-..."}
+                      placeholder={isEdit ? t("form.apiKeyEditPlaceholder") : t("form.apiKeyPlaceholder")}
                     />
                     {isEdit && apiKey === "***" && (
                       <p className="text-xs text-muted-foreground">
-                        API key is set. Clear and type a new value to change it.
+                        {t("form.apiKeySetHint")}
                       </p>
                     )}
                   </div>
@@ -218,7 +222,7 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
               )}
 
               <div className="flex items-center justify-between">
-                <Label htmlFor="enabled">Enabled</Label>
+                <Label htmlFor="enabled">{t("form.enabled")}</Label>
                 <Switch id="enabled" checked={enabled} onCheckedChange={setEnabled} />
               </div>
               {error && (
@@ -229,14 +233,16 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
         </div>
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>
-            {isOAuth ? "Close" : "Cancel"}
+            {isOAuth ? t("form.close") : t("form.cancel")}
           </Button>
           {!isOAuth && (
             <Button
               onClick={handleSubmit}
               disabled={!name.trim() || !isValidSlug(name) || !providerType || loading}
             >
-              {loading ? (isEdit ? "Saving..." : "Creating...") : isEdit ? "Save" : "Create"}
+              {loading
+                ? (isEdit ? t("form.saving") : t("form.creating"))
+                : isEdit ? t("form.save") : t("form.create")}
             </Button>
           )}
         </DialogFooter>
@@ -247,28 +253,30 @@ export function ProviderFormDialog({ open, onOpenChange, provider, onSubmit, exi
 
 // --- Provider type select dropdown ---
 
-function ProviderTypeSelect({ value, hasClaudeCLI, onChange }: {
+function ProviderTypeSelect({ value, hasClaudeCLI, alreadyAddedLabel, providerTypeLabel, onChange }: {
   value: string;
   hasClaudeCLI: boolean;
+  alreadyAddedLabel: string;
+  providerTypeLabel: string;
   onChange: (value: string) => void;
 }) {
   return (
     <div className="space-y-2">
-      <Label>Provider Type *</Label>
+      <Label>{providerTypeLabel}</Label>
       <Select value={value} onValueChange={onChange}>
         <SelectTrigger>
           <SelectValue />
         </SelectTrigger>
         <SelectContent>
-          {PROVIDER_TYPES.map((t) => (
+          {PROVIDER_TYPES.map((pt) => (
             <SelectItem
-              key={t.value}
-              value={t.value}
-              disabled={t.value === "claude_cli" && hasClaudeCLI}
+              key={pt.value}
+              value={pt.value}
+              disabled={pt.value === "claude_cli" && hasClaudeCLI}
             >
-              {t.label}
-              {t.value === "claude_cli" && hasClaudeCLI && (
-                <span className="ml-1 text-xs opacity-60">(already added)</span>
+              {pt.label}
+              {pt.value === "claude_cli" && hasClaudeCLI && (
+                <span className="ml-1 text-xs opacity-60">{alreadyAddedLabel}</span>
               )}
             </SelectItem>
           ))}
diff --git a/ui/web/src/pages/providers/provider-oauth-section.tsx b/ui/web/src/pages/providers/provider-oauth-section.tsx
index 17b45b8f..e10b4592 100644
--- a/ui/web/src/pages/providers/provider-oauth-section.tsx
+++ b/ui/web/src/pages/providers/provider-oauth-section.tsx
@@ -1,9 +1,11 @@
 import { useState, useEffect, useRef, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Loader2, ExternalLink, CheckCircle, ClipboardPaste } from "lucide-react";
 import { useHttp } from "@/hooks/use-ws";
 import { toast } from "@/stores/use-toast-store";
+import i18next from "i18next";
 
 interface OAuthStatus {
   authenticated: boolean;
@@ -17,6 +19,7 @@ interface StartResponse {
 }
 
 export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
+  const { t } = useTranslation("providers");
   const http = useHttp();
   const [status, setStatus] = useState<OAuthStatus | null>(null);
   const [loading, setLoading] = useState(true);
@@ -100,7 +103,7 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
         }, 6 * 60 * 1000);
       }
     } catch (err) {
-      toast.error("OAuth failed", err instanceof Error ? err.message : "Unknown error");
+      toast.error(i18next.t("providers:oauth.oauthFailed"), err instanceof Error ? err.message : "");
     } finally {
       setStarting(false);
     }
@@ -117,7 +120,7 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
       await fetchStatus();
       showSuccess();
     } catch (err) {
-      toast.error("Exchange failed", err instanceof Error ? err.message : "Invalid redirect URL");
+      toast.error(i18next.t("providers:oauth.exchangeFailed"), err instanceof Error ? err.message : "");
     } finally {
       setSubmitting(false);
     }
@@ -127,16 +130,16 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
     try {
       await http.post("/v1/auth/openai/logout");
       setStatus({ authenticated: false });
-      toast.success("Logged out", "OpenAI OAuth token removed");
+      toast.success(i18next.t("providers:oauth.loggedOut"), i18next.t("providers:oauth.loggedOutDesc"));
     } catch (err) {
-      toast.error("Logout failed", err instanceof Error ? err.message : "Unknown error");
+      toast.error("Logout failed", err instanceof Error ? err.message : "");
     }
   };
 
   if (loading) {
     return (
       <div className="flex items-center gap-2 py-4 text-sm text-muted-foreground">
-        <Loader2 className="h-4 w-4 animate-spin" /> Checking authentication status...
+        <Loader2 className="h-4 w-4 animate-spin" /> {t("oauth.checkingStatus")}
       </div>
     );
   }
@@ -148,10 +151,10 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
         <div className="flex items-center gap-2 rounded-md border border-green-500/30 bg-green-500/5 px-4 py-3 text-sm text-green-700 dark:text-green-400">
           <CheckCircle className="h-5 w-5 shrink-0" />
           <div>
-            <p className="font-medium">Authentication successful!</p>
+            <p className="font-medium">{t("oauth.authSuccessful")}</p>
             <p className="text-xs mt-0.5 opacity-80">
-              Provider <code className="rounded bg-muted px-1 font-mono text-xs">openai-codex</code> is
-              now active. Closing in {countdown}s...
+              {t("oauth.activeProvider")} <code className="rounded bg-muted px-1 font-mono text-xs">openai-codex</code>{" "}
+              {t("oauth.closingIn", { count: countdown })}
             </p>
           </div>
         </div>
@@ -166,15 +169,15 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
         <div className="flex items-center gap-2 rounded-md border border-green-500/30 bg-green-500/5 px-3 py-2 text-sm text-green-700 dark:text-green-400">
           <CheckCircle className="h-4 w-4 shrink-0" />
           <span>
-            Authenticated — provider <code className="rounded bg-muted px-1 font-mono text-xs">openai-codex</code> active
+            {t("oauth.authenticated")} <code className="rounded bg-muted px-1 font-mono text-xs">openai-codex</code> {t("oauth.active")}
           </span>
         </div>
         <p className="text-xs text-muted-foreground">
-          Use model prefix <code className="rounded bg-muted px-1 font-mono">openai-codex/</code> in
-          agent config (e.g. openai-codex/gpt-4o). Token refreshes automatically.
+          {t("oauth.modelPrefixHint")} <code className="rounded bg-muted px-1 font-mono">openai-codex/</code>{" "}
+          {t("oauth.modelPrefixExample")}
         </p>
         <Button variant="outline" size="sm" onClick={handleLogout} className="gap-1.5">
-          Remove Token
+          {t("oauth.removeToken")}
         </Button>
       </div>
     );
@@ -182,26 +185,21 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
 
   return (
     <div className="space-y-3">
-      <p className="text-sm text-muted-foreground">
-        Sign in with your ChatGPT account to use your subscription's models
-        without a separate API key.
-      </p>
+      <p className="text-sm text-muted-foreground">{t("oauth.signInDesc")}</p>
       {waitingCallback ? (
         <div className="space-y-3">
           <div className="flex items-center gap-2 rounded-md border border-blue-500/30 bg-blue-500/5 px-3 py-2 text-sm text-blue-700 dark:text-blue-400">
             <Loader2 className="h-4 w-4 shrink-0 animate-spin" />
-            <span>Waiting for authentication... Complete sign-in in the opened window.</span>
+            <span>{t("oauth.waiting")}</span>
           </div>
           <div className="rounded-md border border-amber-500/30 bg-amber-500/5 p-3 space-y-2">
             <p className="text-xs text-amber-700 dark:text-amber-400">
-              <strong>Remote/VPS?</strong> After signing in, your browser will try to open{" "}
-              <code className="text-xs">localhost:1455</code> and show a{" "}
-              <strong>&quot;Can&apos;t reach this page&quot;</strong> error.
-              That&apos;s normal — <strong>copy the full URL from the browser address bar</strong> and paste it below.
+              <strong>{t("oauth.remoteVps")}</strong>{" "}{t("oauth.remoteVpsHint")}{" "}
+              <code className="text-xs">localhost:1455</code>{" "}{t("oauth.remoteVpsError")}
             </p>
             <div className="flex gap-2">
               <Input
-                placeholder="http://localhost:1455/auth/callback?code=...&state=..."
+                placeholder={t("oauth.pasteUrlPlaceholder")}
                 value={pasteUrl}
                 onChange={(e) => setPasteUrl(e.target.value)}
                 onKeyDown={(e) => e.key === "Enter" && handlePasteSubmit()}
@@ -214,7 +212,7 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
                 className="gap-1.5 shrink-0 h-8"
               >
                 {submitting ? <Loader2 className="h-3.5 w-3.5 animate-spin" /> : <ClipboardPaste className="h-3.5 w-3.5" />}
-                Submit
+                {t("oauth.submit")}
               </Button>
             </div>
           </div>
@@ -222,7 +220,7 @@ export function OAuthSection({ onSuccess }: { onSuccess: () => void }) {
       ) : (
         <Button size="sm" onClick={handleStart} disabled={starting} className="gap-1.5">
           {starting ? <Loader2 className="h-3.5 w-3.5 animate-spin" /> : <ExternalLink className="h-3.5 w-3.5" />}
-          {starting ? "Starting..." : "Sign in with ChatGPT"}
+          {starting ? t("oauth.starting") : t("oauth.signInWithChatGPT")}
         </Button>
       )}
     </div>
diff --git a/ui/web/src/pages/providers/providers-page.tsx b/ui/web/src/pages/providers/providers-page.tsx
index 8e8221ce..777976e5 100644
--- a/ui/web/src/pages/providers/providers-page.tsx
+++ b/ui/web/src/pages/providers/providers-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Cpu, Plus, RefreshCw, Pencil, Trash2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -31,6 +32,8 @@ const typeBadge: Record<string, { label: string; variant: "default" | "secondary
 };
 
 export function ProvidersPage() {
+  const { t } = useTranslation("providers");
+  const { t: tc } = useTranslation("common");
   const {
     providers, loading, refresh,
     createProvider, updateProvider, deleteProvider,
@@ -76,15 +79,15 @@ export function ProvidersPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Providers"
-        description="Manage LLM providers"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex gap-2">
             <Button size="sm" onClick={() => { setEditProvider(null); setFormOpen(true); }} className="gap-1">
-              <Plus className="h-3.5 w-3.5" /> Add Provider
+              <Plus className="h-3.5 w-3.5" /> {t("addProvider")}
             </Button>
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
             </Button>
           </div>
         }
@@ -94,7 +97,7 @@ export function ProvidersPage() {
         <SearchInput
           value={search}
           onChange={setSearch}
-          placeholder="Search providers..."
+          placeholder={t("searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -105,20 +108,20 @@ export function ProvidersPage() {
         ) : filtered.length === 0 ? (
           <EmptyState
             icon={Cpu}
-            title={search ? "No matching providers" : "No providers"}
-            description={search ? "Try a different search term." : "Add your first LLM provider to get started."}
+            title={search ? t("noMatchTitle") : t("emptyTitle")}
+            description={search ? t("noMatchDescription") : t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border overflow-x-auto">
             <table className="w-full min-w-[700px] text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Name</th>
-                  <th className="px-4 py-3 text-left font-medium">Type</th>
-                  <th className="px-4 py-3 text-left font-medium">API Base</th>
-                  <th className="px-4 py-3 text-left font-medium">API Key</th>
-                  <th className="px-4 py-3 text-left font-medium">Status</th>
-                  <th className="px-4 py-3 text-right font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.name")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.type")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.apiBase")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.apiKey")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.status")}</th>
+                  <th className="px-4 py-3 text-right font-medium">{t("columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -145,16 +148,16 @@ export function ProvidersPage() {
                       </td>
                       <td className="px-4 py-3">
                         {p.provider_type === "chatgpt_oauth" ? (
-                          <Badge variant="outline" className="text-xs">OAuth Token</Badge>
+                          <Badge variant="outline" className="text-xs">{t("apiKey.oauthToken")}</Badge>
                         ) : p.api_key === "***" ? (
                           <Badge variant="outline" className="font-mono text-xs">***</Badge>
                         ) : (
-                          <span className="text-xs text-muted-foreground">Not set</span>
+                          <span className="text-xs text-muted-foreground">{t("apiKey.notSet")}</span>
                         )}
                       </td>
                       <td className="px-4 py-3">
                         <Badge variant={p.enabled ? "default" : "secondary"}>
-                          {p.enabled ? "Enabled" : "Disabled"}
+                          {p.enabled ? tc("enabled") : tc("disabled")}
                         </Badge>
                       </td>
                       <td className="px-4 py-3 text-right">
@@ -206,10 +209,10 @@ export function ProvidersPage() {
       <ConfirmDeleteDialog
         open={!!deleteTarget}
         onOpenChange={(v) => !v && setDeleteTarget(null)}
-        title="Delete Provider"
-        description={`Are you sure you want to delete "${deleteTarget?.display_name || deleteTarget?.name}"? This action cannot be undone.`}
+        title={t("delete.title")}
+        description={t("delete.description", { name: deleteTarget?.display_name || deleteTarget?.name })}
         confirmValue={deleteTarget?.display_name || deleteTarget?.name || ""}
-        confirmLabel="Delete"
+        confirmLabel={t("delete.confirmLabel")}
         onConfirm={handleDelete}
         loading={deleteLoading}
       />
diff --git a/ui/web/src/pages/sessions/session-detail-page.tsx b/ui/web/src/pages/sessions/session-detail-page.tsx
index a3768570..774defe7 100644
--- a/ui/web/src/pages/sessions/session-detail-page.tsx
+++ b/ui/web/src/pages/sessions/session-detail-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback, useRef, useLayoutEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { ArrowLeft, Trash2, RotateCcw, Info, Eye, Pencil, Check, X } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -44,6 +45,7 @@ export function SessionDetailPage({
   onReset,
   onPatch,
 }: SessionDetailPageProps) {
+  const { t } = useTranslation("sessions");
   const [messages, setMessages] = useState<ChatMessage[]>([]);
   const [summary, setSummary] = useState<string | null>(null);
   const [loading, setLoading] = useState(true);
@@ -187,7 +189,7 @@ export function SessionDetailPage({
               {session.metadata?.peer_kind && (
                 <Badge variant="outline">{session.metadata.peer_kind}</Badge>
               )}
-              <span>{session.messageCount} messages</span>
+              <span>{session.messageCount} {t("detail.messages")}</span>
               <span>{formatDate(session.updated)}</span>
               {session.inputTokens != null && (
                 <span>
@@ -199,10 +201,10 @@ export function SessionDetailPage({
         </div>
         <div className="flex gap-2">
           <Button variant="outline" size="sm" onClick={() => setConfirmReset(true)} className="gap-1">
-            <RotateCcw className="h-3.5 w-3.5" /> Reset
+            <RotateCcw className="h-3.5 w-3.5" /> {t("detail.reset")}
           </Button>
           <Button variant="destructive" size="sm" onClick={() => setConfirmDelete(true)} className="gap-1">
-            <Trash2 className="h-3.5 w-3.5" /> Delete
+            <Trash2 className="h-3.5 w-3.5" /> {t("detail.delete")}
           </Button>
         </div>
       </div>
@@ -220,7 +222,7 @@ export function SessionDetailPage({
           </div>
         ) : messages.length === 0 ? (
           <div className="py-12 text-center text-sm text-muted-foreground">
-            No messages in this session
+            {t("detail.noMessages")}
           </div>
         ) : (
           <div className="mx-auto max-w-3xl space-y-4">
@@ -238,9 +240,9 @@ export function SessionDetailPage({
       <ConfirmDialog
         open={confirmDelete}
         onOpenChange={setConfirmDelete}
-        title="Delete Session"
-        description="This will permanently delete all messages in this session."
-        confirmLabel="Delete"
+        title={t("detail.deleteTitle")}
+        description={t("detail.deleteDescription")}
+        confirmLabel={t("detail.confirmDelete")}
         variant="destructive"
         onConfirm={async () => {
           await onDelete(session.key);
@@ -252,9 +254,9 @@ export function SessionDetailPage({
       <ConfirmDialog
         open={confirmReset}
         onOpenChange={setConfirmReset}
-        title="Reset Session"
-        description="This will clear all messages but keep the session."
-        confirmLabel="Reset"
+        title={t("detail.resetTitle")}
+        description={t("detail.resetDescription")}
+        confirmLabel={t("detail.confirmReset")}
         onConfirm={async () => {
           await onReset(session.key);
           setConfirmReset(false);
@@ -266,6 +268,7 @@ export function SessionDetailPage({
 }
 
 function SystemMessageBlock({ content }: { content: string }) {
+  const { t } = useTranslation("sessions");
   const [expanded, setExpanded] = useState(false);
   // Extract the first line as title, rest as body
   const lines = content.split("\n");
@@ -276,7 +279,7 @@ function SystemMessageBlock({ content }: { content: string }) {
     <div className="mx-auto flex max-w-3xl items-start gap-2 rounded-md border border-dashed border-muted-foreground/30 bg-muted/30 px-4 py-2">
       <Info className="mt-0.5 h-4 w-4 shrink-0 text-muted-foreground" />
       <div className="min-w-0 text-xs text-muted-foreground">
-        <span className="font-medium">{title || "System Message"}</span>
+        <span className="font-medium">{title || t("detail.systemMessage")}</span>
         {body && (
           <>
             <button
@@ -284,7 +287,7 @@ function SystemMessageBlock({ content }: { content: string }) {
               onClick={() => setExpanded((v) => !v)}
               className="ml-1 cursor-pointer text-primary hover:underline"
             >
-              {expanded ? "hide" : "show details"}
+              {expanded ? t("detail.hide") : t("detail.showDetails")}
             </button>
             {expanded && (
               <div className="mt-2">
@@ -301,6 +304,7 @@ function SystemMessageBlock({ content }: { content: string }) {
 const SUMMARY_MAX_HEIGHT = 72; // ~3 lines of text
 
 function SummaryBlock({ text }: { text: string }) {
+  const { t } = useTranslation("sessions");
   const [expanded, setExpanded] = useState(false);
   const [needsTruncation, setNeedsTruncation] = useState(false);
   const contentRef = useRef<HTMLDivElement>(null);
@@ -313,7 +317,7 @@ function SummaryBlock({ text }: { text: string }) {
 
   return (
     <div className="border-b bg-muted/50 px-6 py-3 text-sm">
-      <span className="font-medium">Summary: </span>
+      <span className="font-medium">{t("detail.summary")}: </span>
       <div
         ref={contentRef}
         className="mt-1 overflow-hidden transition-[max-height] duration-200"
@@ -327,7 +331,7 @@ function SummaryBlock({ text }: { text: string }) {
           onClick={() => setExpanded((v) => !v)}
           className="mt-1 cursor-pointer text-xs font-medium text-primary hover:underline"
         >
-          {expanded ? "Show less" : "Show more"}
+          {expanded ? t("detail.showLess") : t("detail.showMore")}
         </button>
       )}
     </div>
diff --git a/ui/web/src/pages/sessions/sessions-page.tsx b/ui/web/src/pages/sessions/sessions-page.tsx
index 7e633dad..db552827 100644
--- a/ui/web/src/pages/sessions/sessions-page.tsx
+++ b/ui/web/src/pages/sessions/sessions-page.tsx
@@ -1,5 +1,6 @@
 import { useState } from "react";
 import { useParams, useNavigate } from "react-router";
+import { useTranslation } from "react-i18next";
 import { History } from "lucide-react";
 import { PageHeader } from "@/components/shared/page-header";
 import { EmptyState } from "@/components/shared/empty-state";
@@ -15,6 +16,7 @@ import { formatRelativeTime } from "@/lib/format";
 import type { SessionInfo } from "@/types/session";
 
 export function SessionsPage() {
+  const { t } = useTranslation("sessions");
   const { key: detailKey } = useParams<{ key: string }>();
   const navigate = useNavigate();
   const [search, setSearch] = useState("");
@@ -63,13 +65,13 @@ export function SessionsPage() {
 
   return (
     <div className="p-4 sm:p-6">
-      <PageHeader title="Sessions" description="Browse conversation sessions" />
+      <PageHeader title={t("title")} description={t("description")} />
 
       <div className="mt-4">
         <SearchInput
           value={search}
           onChange={setSearch}
-          placeholder="Search sessions..."
+          placeholder={t("searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -80,23 +82,19 @@ export function SessionsPage() {
         ) : filtered.length === 0 ? (
           <EmptyState
             icon={History}
-            title={search ? "No matching sessions" : "No sessions yet"}
-            description={
-              search
-                ? "Try a different search term."
-                : "Sessions will appear here once you start chatting."
-            }
+            title={search ? t("noMatchTitle") : t("emptyTitle")}
+            description={search ? t("noMatchDescription") : t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border overflow-x-auto">
             <table className="w-full min-w-[600px]">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left text-sm font-medium">Session</th>
-                  <th className="px-4 py-3 text-left text-sm font-medium">Agent</th>
-                  <th className="px-4 py-3 text-left text-sm font-medium">Channel</th>
-                  <th className="px-4 py-3 text-right text-sm font-medium">Messages</th>
-                  <th className="px-4 py-3 text-right text-sm font-medium">Updated</th>
+                  <th className="px-4 py-3 text-left text-sm font-medium">{t("columns.session")}</th>
+                  <th className="px-4 py-3 text-left text-sm font-medium">{t("columns.agent")}</th>
+                  <th className="px-4 py-3 text-left text-sm font-medium">{t("columns.channel")}</th>
+                  <th className="px-4 py-3 text-right text-sm font-medium">{t("columns.messages")}</th>
+                  <th className="px-4 py-3 text-right text-sm font-medium">{t("columns.updated")}</th>
                 </tr>
               </thead>
               <tbody>
diff --git a/ui/web/src/pages/setup/setup-complete-modal.tsx b/ui/web/src/pages/setup/setup-complete-modal.tsx
index 38d29fcd..5217c2f7 100644
--- a/ui/web/src/pages/setup/setup-complete-modal.tsx
+++ b/ui/web/src/pages/setup/setup-complete-modal.tsx
@@ -1,4 +1,5 @@
 import { motion } from "framer-motion";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -13,11 +14,12 @@ interface SetupCompleteModalProps {
 }
 
 export function SetupCompleteModal({ open, onGoToDashboard }: SetupCompleteModalProps) {
+  const { t } = useTranslation("setup");
   return (
     <Dialog open={open} onOpenChange={() => {/* blocked */}}>
       <DialogContent className="sm:max-w-md" onInteractOutside={(e) => e.preventDefault()}>
         <DialogHeader>
-          <DialogTitle className="text-center">Setup Complete!</DialogTitle>
+          <DialogTitle className="text-center">{t("complete.title")}</DialogTitle>
         </DialogHeader>
 
         <div className="flex flex-col items-center gap-6 py-6">
@@ -39,15 +41,15 @@ export function SetupCompleteModal({ open, onGoToDashboard }: SetupCompleteModal
 
           <div className="space-y-2 text-center">
             <p className="text-sm font-medium text-foreground">
-              Your system is ready to go!
+              {t("complete.ready")}
             </p>
             <p className="text-xs text-muted-foreground">
-              Provider, agent, and channel have been configured. You can manage them anytime from the dashboard.
+              {t("complete.description")}
             </p>
           </div>
 
           <Button onClick={onGoToDashboard} className="w-full sm:w-auto px-8">
-            Go to Dashboard
+            {t("complete.goToDashboard")}
           </Button>
         </div>
       </DialogContent>
diff --git a/ui/web/src/pages/setup/setup-layout.tsx b/ui/web/src/pages/setup/setup-layout.tsx
index 83d96c3b..a5bc738a 100644
--- a/ui/web/src/pages/setup/setup-layout.tsx
+++ b/ui/web/src/pages/setup/setup-layout.tsx
@@ -1,11 +1,14 @@
+import { useTranslation } from "react-i18next";
+
 export function SetupLayout({ children }: { children: React.ReactNode }) {
+  const { t } = useTranslation("setup");
   return (
     <div className="flex min-h-screen items-center justify-center bg-background px-4 py-8">
       <div className="w-full max-w-2xl space-y-6">
         <div className="text-center">
           <h1 className="text-3xl font-semibold tracking-tight">GoClaw Setup</h1>
           <p className="mt-2 text-sm text-muted-foreground">
-            Let's get your gateway up and running
+            {t("layout.subtitle", "Let's get your gateway up and running")}
           </p>
         </div>
         {children}
diff --git a/ui/web/src/pages/setup/setup-stepper.tsx b/ui/web/src/pages/setup/setup-stepper.tsx
index 10c5b758..57a2cd31 100644
--- a/ui/web/src/pages/setup/setup-stepper.tsx
+++ b/ui/web/src/pages/setup/setup-stepper.tsx
@@ -1,11 +1,5 @@
 import { Check } from "lucide-react";
-
-const STEPS: { num: number; label: string; sublabel?: string }[] = [
-  { num: 1, label: "Provider" },
-  { num: 2, label: "Model" },
-  { num: 3, label: "Agent" },
-  { num: 4, label: "Channel", sublabel: "(Optional)" },
-];
+import { useTranslation } from "react-i18next";
 
 interface SetupStepperProps {
   currentStep: 1 | 2 | 3 | 4;
@@ -13,6 +7,15 @@ interface SetupStepperProps {
 }
 
 export function SetupStepper({ currentStep, completedSteps }: SetupStepperProps) {
+  const { t } = useTranslation("setup");
+
+  const STEPS: { num: number; label: string; sublabel?: string }[] = [
+    { num: 1, label: t("steps.provider") },
+    { num: 2, label: t("steps.model") },
+    { num: 3, label: t("steps.agent") },
+    { num: 4, label: t("steps.channel"), sublabel: t("steps.channelOptional") },
+  ];
+
   return (
     <div className="flex items-center justify-center gap-0">
       {STEPS.map((step, i) => {
diff --git a/ui/web/src/pages/setup/step-agent.tsx b/ui/web/src/pages/setup/step-agent.tsx
index 3c46b7dd..61e2501a 100644
--- a/ui/web/src/pages/setup/step-agent.tsx
+++ b/ui/web/src/pages/setup/step-agent.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useMemo, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -25,6 +26,7 @@ interface StepAgentProps {
 }
 
 export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
+  const { t } = useTranslation("setup");
   const { createAgent, deleteAgent, resummonAgent } = useAgents();
 
   const [displayName] = useState("GoClaw");
@@ -72,7 +74,7 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
 
   const handleCreate = async () => {
     if (!agentKey.trim() || !isValidSlug(agentKey)) return;
-    if (!provider) { setError("No provider available"); return; }
+    if (!provider) { setError(t("agent.errors.noProvider")); return; }
 
     setLoading(true);
     setError("");
@@ -97,7 +99,7 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
       setCreatedAgent({ id: result.id, name: displayName.trim() || agentKey });
       setSummoningOpen(true);
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to create agent");
+      setError(err instanceof Error ? err.message : t("agent.errors.failedCreate"));
     } finally {
       setLoading(false);
     }
@@ -119,7 +121,7 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
     setCreatedAgent(null);
     setSummoningOpen(false);
     setSummoningOutcome("pending");
-    setError("Summoning failed. Please adjust your settings and try again.");
+    setError(t("agent.summoningFailed"));
   };
 
   return (
@@ -128,21 +130,21 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
         <CardContent className="space-y-4 pt-6">
           <TooltipProvider>
             <div className="space-y-1">
-              <h2 className="text-lg font-semibold">Create Your First Agent</h2>
+              <h2 className="text-lg font-semibold">{t("agent.title")}</h2>
               <p className="text-sm text-muted-foreground">
-                An agent is your AI assistant. Customize its name and personality.
+                {t("agent.description")}
               </p>
             </div>
 
             {/* Provider + model info */}
             <div className="flex flex-wrap items-center gap-x-4 gap-y-1">
               <div className="flex items-center gap-2">
-                <span className="text-sm text-muted-foreground">Provider:</span>
+                <span className="text-sm text-muted-foreground">{t("agent.provider")}</span>
                 <Badge variant="secondary">{providerLabel}</Badge>
               </div>
               {model && (
                 <div className="flex items-center gap-2">
-                  <span className="text-sm text-muted-foreground">Model:</span>
+                  <span className="text-sm text-muted-foreground">{t("agent.model")}</span>
                   <Badge variant="outline">{model}</Badge>
                 </div>
               )}
@@ -151,8 +153,8 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
             <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
               <div className="space-y-2">
                 <Label className="inline-flex items-center gap-1.5">
-                  Display Name
-                  <InfoTip text="Will be auto-generated during summoning based on the agent personality." />
+                  {t("agent.displayName")}
+                  <InfoTip text={t("agent.displayNameHint")} />
                 </Label>
                 <Input
                   value={displayName}
@@ -162,14 +164,14 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
               </div>
               <div className="space-y-2">
                 <Label className="inline-flex items-center gap-1.5">
-                  Agent Key
-                  <InfoTip text="Unique identifier for the agent. Lowercase letters, numbers, and hyphens only." />
+                  {t("agent.agentKey")}
+                  <InfoTip text={t("agent.agentKeyHint")} />
                 </Label>
                 <Input
                   value={agentKey}
                   onChange={(e) => { setKeyTouched(true); setAgentKey(e.target.value); }}
                   onBlur={() => setAgentKey(slugify(agentKey))}
-                  placeholder="my-agent"
+                  placeholder={t("agent.agentKeyPlaceholder")}
                 />
               </div>
             </div>
@@ -177,8 +179,8 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
             {/* Prompt / description */}
             <div className="space-y-3">
               <Label className="inline-flex items-center gap-1.5">
-                Agent Personality
-                <InfoTip text="Describe your agent's role and behavior. AI will generate context files from this during summoning." />
+                {t("agent.personality")}
+                <InfoTip text={t("agent.personalityHint")} />
               </Label>
               <div className="flex flex-wrap gap-1.5">
                 {AGENT_PRESETS.map((preset) => (
@@ -195,16 +197,16 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
               <Textarea
                 value={description}
                 onChange={(e) => setDescription(e.target.value)}
-                placeholder="Describe your agent's personality, purpose, and behavior..."
+                placeholder={t("agent.personalityPlaceholder")}
                 className="min-h-[120px]"
               />
               <p className="text-xs text-muted-foreground">
-                Customize this prompt to shape your agent's personality and expertise.
+                {t("agent.personalityHintBottom")}
               </p>
               <div className="flex items-center justify-between gap-4 rounded-md border px-3 py-2.5">
                 <div className="space-y-0.5">
-                  <Label htmlFor="setup-self-evolve" className="text-sm font-normal">Self-Evolution</Label>
-                  <p className="text-xs text-muted-foreground">Allow agent to evolve its communication style over time via SOUL.md</p>
+                  <Label htmlFor="setup-self-evolve" className="text-sm font-normal">{t("agent.selfEvolve")}</Label>
+                  <p className="text-xs text-muted-foreground">{t("agent.selfEvolveDesc")}</p>
                 </div>
                 <Switch id="setup-self-evolve" checked={selfEvolve} onCheckedChange={setSelfEvolve} />
               </div>
@@ -217,7 +219,7 @@ export function StepAgent({ provider, model, onComplete }: StepAgentProps) {
                 onClick={handleCreate}
                 disabled={loading || !agentKey.trim() || !isValidSlug(agentKey) || !description.trim()}
               >
-                {loading ? "Creating..." : "Create Agent"}
+                {loading ? t("agent.creating") : t("agent.create")}
               </Button>
             </div>
           </TooltipProvider>
diff --git a/ui/web/src/pages/setup/step-channel.tsx b/ui/web/src/pages/setup/step-channel.tsx
index 5bfb6343..2310c6c9 100644
--- a/ui/web/src/pages/setup/step-channel.tsx
+++ b/ui/web/src/pages/setup/step-channel.tsx
@@ -1,4 +1,5 @@
 import { useState, useCallback } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -27,6 +28,7 @@ interface StepChannelProps {
 }
 
 export function StepChannel({ agent, onComplete, onSkip }: StepChannelProps) {
+  const { t } = useTranslation("setup");
   const { createInstance } = useChannelInstances();
 
   const [channelType, setChannelType] = useState("telegram");
@@ -50,11 +52,11 @@ export function StepChannel({ agent, onComplete, onSkip }: StepChannelProps) {
   }, []);
 
   const handleCreate = async () => {
-    if (!agent) { setError("No agent available"); return; }
+    if (!agent) { setError(t("channel.errors.noAgent")); return; }
 
     const missing = credsFields.filter((f) => f.required && !credsValues[f.key]);
     if (missing.length > 0) {
-      setError(`Required: ${missing.map((f) => f.label).join(", ")}`);
+      setError(t("channel.errors.requiredFields", { fields: missing.map((f) => f.label).join(", ") }));
       return;
     }
 
@@ -81,7 +83,7 @@ export function StepChannel({ agent, onComplete, onSkip }: StepChannelProps) {
       });
       onComplete();
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to create channel");
+      setError(err instanceof Error ? err.message : t("channel.errors.failedCreate"));
     } finally {
       setLoading(false);
     }
@@ -95,27 +97,27 @@ export function StepChannel({ agent, onComplete, onSkip }: StepChannelProps) {
         <TooltipProvider>
         <div className="flex items-start justify-between gap-4">
           <div className="space-y-1">
-            <h2 className="text-lg font-semibold">Connect a Channel</h2>
+            <h2 className="text-lg font-semibold">{t("channel.title")}</h2>
             <p className="text-sm text-muted-foreground">
-              Connect a messaging platform to your agent. You can always add channels later.
+              {t("channel.description")}
             </p>
           </div>
           <Button variant="outline" size="sm" onClick={onSkip}>
-            Skip
+            {t("channel.skip")}
           </Button>
         </div>
 
         {/* Agent badge */}
         <div className="flex items-center gap-2">
-          <span className="text-sm text-muted-foreground">Agent:</span>
+          <span className="text-sm text-muted-foreground">{t("channel.agent")}</span>
           <Badge variant="secondary">{agentLabel}</Badge>
         </div>
 
         <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
           <div className="space-y-2">
             <Label className="inline-flex items-center gap-1.5">
-              Channel Type
-              <InfoTip text="The messaging platform to connect. E.g. Telegram, Discord, Zalo." />
+              {t("channel.channelType")}
+              <InfoTip text={t("channel.channelTypeHint")} />
             </Label>
             <Select value={channelType} onValueChange={handleTypeChange}>
               <SelectTrigger><SelectValue /></SelectTrigger>
@@ -129,28 +131,28 @@ export function StepChannel({ agent, onComplete, onSkip }: StepChannelProps) {
 
           <div className="space-y-2">
             <Label className="inline-flex items-center gap-1.5">
-              Name
-              <InfoTip text="Internal identifier for this channel instance. Auto-generated from channel type." />
+              {t("channel.name")}
+              <InfoTip text={t("channel.nameHint")} />
             </Label>
-            <Input value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder="my-telegram" />
+            <Input value={name} onChange={(e) => setName(slugify(e.target.value))} placeholder={t("channel.namePlaceholder")} />
           </div>
         </div>
 
         {displayName !== undefined && (
           <div className="space-y-2">
             <Label className="inline-flex items-center gap-1.5">
-              Display Name
-              <InfoTip text="A friendly name shown in the UI. Optional." />
+              {t("channel.displayName")}
+              <InfoTip text={t("channel.displayNameHint")} />
             </Label>
-            <Input value={displayName} onChange={(e) => setDisplayName(e.target.value)} placeholder="Sales Bot" />
+            <Input value={displayName} onChange={(e) => setDisplayName(e.target.value)} placeholder={t("channel.displayNamePlaceholder")} />
           </div>
         )}
 
         {credsFields.length > 0 && (
           <fieldset className="rounded-md border p-3 space-y-3">
-            <legend className="px-1 text-sm font-medium">Credentials</legend>
+            <legend className="px-1 text-sm font-medium">{t("channel.credentials")}</legend>
             <ChannelFields fields={credsFields} values={credsValues} onChange={handleCredsChange} idPrefix="setup-cred" />
-            <p className="text-xs text-muted-foreground">Encrypted server-side. Never returned in API responses.</p>
+            <p className="text-xs text-muted-foreground">{t("channel.credentialsHint")}</p>
           </fieldset>
         )}
 
@@ -158,10 +160,10 @@ export function StepChannel({ agent, onComplete, onSkip }: StepChannelProps) {
 
         <div className="flex justify-end gap-2">
           <Button variant="outline" onClick={onSkip} disabled={loading}>
-            Skip & Finish
+            {t("channel.skipFinish")}
           </Button>
           <Button onClick={handleCreate} disabled={loading}>
-            {loading ? "Creating..." : "Create Channel"}
+            {loading ? t("channel.creating") : t("channel.create")}
           </Button>
         </div>
         </TooltipProvider>
diff --git a/ui/web/src/pages/setup/step-model.tsx b/ui/web/src/pages/setup/step-model.tsx
index d3c6946f..bbbac44f 100644
--- a/ui/web/src/pages/setup/step-model.tsx
+++ b/ui/web/src/pages/setup/step-model.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { CheckCircle2 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Label } from "@/components/ui/label";
 import { Badge } from "@/components/ui/badge";
@@ -17,6 +18,7 @@ interface StepModelProps {
 }
 
 export function StepModel({ provider, onComplete }: StepModelProps) {
+  const { t } = useTranslation("setup");
   const { models, loading: modelsLoading } = useProviderModels(provider.id, provider.provider_type);
   const { verify, verifying, result: verifyResult, reset: resetVerify } = useProviderVerify();
 
@@ -33,7 +35,7 @@ export function StepModel({ provider, onComplete }: StepModelProps) {
     setError("");
     const res = await verify(provider.id, model.trim());
     if (!res?.valid) {
-      setError(res?.error || "Verification failed. Check your API key and model.");
+      setError(res?.error || t("model.verificationFailed"));
     }
   };
 
@@ -44,32 +46,32 @@ export function StepModel({ provider, onComplete }: StepModelProps) {
       <CardContent className="space-y-4 pt-6">
         <TooltipProvider>
           <div className="space-y-1">
-            <h2 className="text-lg font-semibold">Select & Verify Model</h2>
+            <h2 className="text-lg font-semibold">{t("model.title")}</h2>
             <p className="text-sm text-muted-foreground">
-              Choose a model and verify that your provider connection works.
+              {t("model.description")}
             </p>
           </div>
 
           {/* Provider summary */}
           <div className="flex items-center gap-2">
-            <span className="text-sm text-muted-foreground">Provider:</span>
+            <span className="text-sm text-muted-foreground">{t("model.provider")}</span>
             <Badge variant="secondary">{providerLabel}</Badge>
           </div>
 
           <div className="space-y-2">
             <Label className="inline-flex items-center gap-1.5">
-              Model *
-              <InfoTip text="The AI model to use. Select from the list or type a model ID manually if not listed." />
+              {t("model.model")}
+              <InfoTip text={t("model.modelHint")} />
             </Label>
             <Combobox
               value={model}
               onChange={setModel}
               options={models.map((m) => ({ value: m.id, label: m.name || m.id }))}
-              placeholder={modelsLoading ? "Loading models..." : "Select or type a model ID"}
+              placeholder={modelsLoading ? t("model.loadingModels") : t("model.selectModel")}
             />
             {!modelsLoading && models.length === 0 && (
               <p className="text-xs text-muted-foreground">
-                This provider doesn't list models — type the model ID manually.
+                {t("model.noModelsHint")}
               </p>
             )}
           </div>
@@ -80,9 +82,9 @@ export function StepModel({ provider, onComplete }: StepModelProps) {
             <div className="flex items-center gap-2 rounded-md border border-emerald-200 bg-emerald-50 p-3 dark:border-emerald-900 dark:bg-emerald-950">
               <CheckCircle2 className="h-5 w-5 text-emerald-600 dark:text-emerald-400" />
               <div>
-                <p className="text-sm font-medium text-emerald-700 dark:text-emerald-300">Model verified</p>
+                <p className="text-sm font-medium text-emerald-700 dark:text-emerald-300">{t("model.modelVerified")}</p>
                 <p className="text-xs text-muted-foreground">
-                  <code className="font-mono">{model}</code> is working correctly
+                  {t("model.modelVerifiedDesc", { model })}
                 </p>
               </div>
             </div>
@@ -94,10 +96,10 @@ export function StepModel({ provider, onComplete }: StepModelProps) {
               onClick={handleVerify}
               disabled={!model.trim() || verifying || isVerified}
             >
-              {verifying ? "Verifying..." : isVerified ? "Verified" : "Verify"}
+              {verifying ? t("model.verifying") : isVerified ? t("model.verified") : t("model.verify")}
             </Button>
             <Button onClick={() => onComplete(model.trim())} disabled={!isVerified}>
-              Continue
+              {t("model.continue")}
             </Button>
           </div>
         </TooltipProvider>
diff --git a/ui/web/src/pages/setup/step-provider.tsx b/ui/web/src/pages/setup/step-provider.tsx
index dae45d4d..f02c8d42 100644
--- a/ui/web/src/pages/setup/step-provider.tsx
+++ b/ui/web/src/pages/setup/step-provider.tsx
@@ -1,4 +1,5 @@
 import { useState, useMemo } from "react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
@@ -23,6 +24,7 @@ interface StepProviderProps {
 }
 
 export function StepProvider({ onComplete }: StepProviderProps) {
+  const { t } = useTranslation("setup");
   const { createProvider } = useProviders();
 
   const [providerType, setProviderType] = useState("openrouter");
@@ -51,7 +53,7 @@ export function StepProvider({ onComplete }: StepProviderProps) {
   );
 
   const handleCreate = async () => {
-    if (!isCLI && !apiKey.trim()) { setError("API key is required"); return; }
+    if (!isCLI && !apiKey.trim()) { setError(t("provider.errors.apiKeyRequired")); return; }
     setLoading(true);
     setError("");
     try {
@@ -64,7 +66,7 @@ export function StepProvider({ onComplete }: StepProviderProps) {
       }) as ProviderData;
       onComplete(provider);
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to create provider");
+      setError(err instanceof Error ? err.message : t("provider.errors.failedCreate"));
     } finally {
       setLoading(false);
     }
@@ -75,19 +77,19 @@ export function StepProvider({ onComplete }: StepProviderProps) {
       <CardContent className="space-y-4 pt-6">
         <TooltipProvider>
           <div className="space-y-1">
-            <h2 className="text-lg font-semibold">Configure LLM Provider</h2>
+            <h2 className="text-lg font-semibold">{t("provider.title")}</h2>
             <p className="text-sm text-muted-foreground">
               {isCLI
-                ? "Connect using your local Claude CLI installation. No API key needed."
-                : "Connect to an AI provider to power your agents. You'll need an API key."}
+                ? t("provider.descriptionCli")
+                : t("provider.description")}
             </p>
           </div>
 
           <div className="grid grid-cols-1 gap-4 sm:grid-cols-2">
             <div className="space-y-2">
               <Label className="inline-flex items-center gap-1.5">
-                Provider Type
-                <InfoTip text="The LLM service you want to connect. OpenRouter is recommended for access to multiple models." />
+                {t("provider.providerType")}
+                <InfoTip text={t("provider.providerTypeHint")} />
               </Label>
               <Select value={providerType} onValueChange={handleTypeChange}>
                 <SelectTrigger><SelectValue /></SelectTrigger>
@@ -100,8 +102,8 @@ export function StepProvider({ onComplete }: StepProviderProps) {
             </div>
             <div className="space-y-2">
               <Label className="inline-flex items-center gap-1.5">
-                Name
-                <InfoTip text="Internal identifier for this provider. Auto-generated from provider type." />
+                {t("provider.name")}
+                <InfoTip text={t("provider.nameHint")} />
               </Label>
               <Input value={name} onChange={(e) => setName(slugify(e.target.value))} />
             </div>
@@ -113,8 +115,8 @@ export function StepProvider({ onComplete }: StepProviderProps) {
             <>
               <div className="space-y-2">
                 <Label className="inline-flex items-center gap-1.5">
-                  API Key *
-                  <InfoTip text="Your provider's secret key. Encrypted server-side and never exposed in API responses." />
+                  {t("provider.apiKey")}
+                  <InfoTip text={t("provider.apiKeyHint")} />
                 </Label>
                 <Input
                   type="password"
@@ -126,8 +128,8 @@ export function StepProvider({ onComplete }: StepProviderProps) {
 
               <div className="space-y-2">
                 <Label className="inline-flex items-center gap-1.5">
-                  API Base URL
-                  <InfoTip text="The endpoint URL for API requests. Auto-filled based on provider type. Override only if using a custom proxy." />
+                  {t("provider.apiBase")}
+                  <InfoTip text={t("provider.apiBaseHint")} />
                 </Label>
                 <Input
                   value={apiBase}
@@ -142,7 +144,7 @@ export function StepProvider({ onComplete }: StepProviderProps) {
 
           <div className="flex justify-end">
             <Button onClick={handleCreate} disabled={loading || (!isCLI && !apiKey.trim())}>
-              {loading ? "Creating..." : "Create Provider"}
+              {loading ? t("provider.creating") : t("provider.create")}
             </Button>
           </div>
         </TooltipProvider>
diff --git a/ui/web/src/pages/skills/skill-detail-dialog.tsx b/ui/web/src/pages/skills/skill-detail-dialog.tsx
index ed0559a0..f58e5427 100644
--- a/ui/web/src/pages/skills/skill-detail-dialog.tsx
+++ b/ui/web/src/pages/skills/skill-detail-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback, useMemo } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -34,6 +35,7 @@ export function SkillDetailDialog({
   getSkillFiles,
   getSkillFileContent,
 }: SkillDetailDialogProps) {
+  const { t } = useTranslation("skills");
   const hasFiles = !!skill.id;
 
   // Version state
@@ -126,8 +128,8 @@ export function SkillDetailDialog({
 
         <Tabs defaultValue="content" className="flex-1 overflow-hidden flex flex-col" onValueChange={handleTabChange}>
           <TabsList>
-            <TabsTrigger value="content">Content</TabsTrigger>
-            {hasFiles && <TabsTrigger value="files">Files</TabsTrigger>}
+            <TabsTrigger value="content">{t("detail.content")}</TabsTrigger>
+            {hasFiles && <TabsTrigger value="files">{t("detail.files")}</TabsTrigger>}
           </TabsList>
 
           <TabsContent value="content" className="flex-1 overflow-y-auto mt-2">
@@ -136,7 +138,7 @@ export function SkillDetailDialog({
                 <MarkdownRenderer content={skill.content} />
               </div>
             ) : (
-              <p className="text-sm text-muted-foreground">No content available.</p>
+              <p className="text-sm text-muted-foreground">{t("detail.noContent")}</p>
             )}
           </TabsContent>
 
@@ -144,7 +146,7 @@ export function SkillDetailDialog({
             <TabsContent value="files" className="flex-1 overflow-hidden flex flex-col mt-2 gap-2">
               {versions && versions.versions.length > 1 && (
                 <div className="flex items-center gap-2">
-                  <span className="text-sm text-muted-foreground">Version:</span>
+                  <span className="text-sm text-muted-foreground">{t("detail.version")}</span>
                   <Select
                     value={String(selectedVersion ?? versions.current)}
                     onValueChange={(v) => setSelectedVersion(Number(v))}
@@ -155,7 +157,7 @@ export function SkillDetailDialog({
                     <SelectContent>
                       {versions.versions.map((v) => (
                         <SelectItem key={v} value={String(v)}>
-                          v{v}{v === versions.current ? " (current)" : ""}
+                          v{v}{v === versions.current ? ` ${t("detail.current")}` : ""}
                         </SelectItem>
                       ))}
                     </SelectContent>
diff --git a/ui/web/src/pages/skills/skill-edit-dialog.tsx b/ui/web/src/pages/skills/skill-edit-dialog.tsx
index b852da1f..06002ea2 100644
--- a/ui/web/src/pages/skills/skill-edit-dialog.tsx
+++ b/ui/web/src/pages/skills/skill-edit-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { X } from "lucide-react";
 import {
   Dialog,
@@ -28,6 +29,7 @@ interface SkillEditDialogProps {
 }
 
 export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps) {
+  const { t } = useTranslation("skills");
   const [name, setName] = useState(skill.name);
   const [description, setDescription] = useState(skill.description);
   const [visibility, setVisibility] = useState(skill.visibility ?? "private");
@@ -44,9 +46,9 @@ export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps
   }, [skill]);
 
   const addTag = () => {
-    const t = tagInput.trim().toLowerCase();
-    if (t && !tags.includes(t)) {
-      setTags([...tags, t]);
+    const tag = tagInput.trim().toLowerCase();
+    if (tag && !tags.includes(tag)) {
+      setTags([...tags, tag]);
     }
     setTagInput("");
   };
@@ -63,7 +65,7 @@ export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps
       await onSave(skill.id, { name, description, visibility, tags });
       onClose();
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Failed to save");
+      setError(err instanceof Error ? err.message : t("edit.save"));
     } finally {
       setLoading(false);
     }
@@ -73,12 +75,12 @@ export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps
     <Dialog open onOpenChange={() => onClose()}>
       <DialogContent className="sm:max-w-md">
         <DialogHeader>
-          <DialogTitle>Edit Skill</DialogTitle>
+          <DialogTitle>{t("edit.title")}</DialogTitle>
         </DialogHeader>
 
         <div className="flex flex-col gap-4">
           <div className="space-y-1.5">
-            <Label htmlFor="skill-name">Name</Label>
+            <Label htmlFor="skill-name">{t("edit.name")}</Label>
             <Input
               id="skill-name"
               value={name}
@@ -87,7 +89,7 @@ export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps
           </div>
 
           <div className="space-y-1.5">
-            <Label htmlFor="skill-desc">Description</Label>
+            <Label htmlFor="skill-desc">{t("edit.description")}</Label>
             <Textarea
               id="skill-desc"
               value={description}
@@ -97,21 +99,21 @@ export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps
           </div>
 
           <div className="space-y-1.5">
-            <Label>Visibility</Label>
+            <Label>{t("edit.visibility")}</Label>
             <Select value={visibility} onValueChange={setVisibility}>
               <SelectTrigger>
                 <SelectValue />
               </SelectTrigger>
               <SelectContent>
-                <SelectItem value="private">Private (owner only)</SelectItem>
-                <SelectItem value="internal">Internal (granted agents/users)</SelectItem>
-                <SelectItem value="public">Public (all agents)</SelectItem>
+                <SelectItem value="private">{t("edit.privateOption")}</SelectItem>
+                <SelectItem value="internal">{t("edit.internalOption")}</SelectItem>
+                <SelectItem value="public">{t("edit.publicOption")}</SelectItem>
               </SelectContent>
             </Select>
           </div>
 
           <div className="space-y-1.5">
-            <Label>Tags</Label>
+            <Label>{t("edit.tags")}</Label>
             <div className="flex gap-2">
               <Input
                 value={tagInput}
@@ -119,11 +121,11 @@ export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps
                 onKeyDown={(e) => {
                   if (e.key === "Enter") { e.preventDefault(); addTag(); }
                 }}
-                placeholder="Add tag..."
+                placeholder={t("edit.addTag")}
                 className="flex-1"
               />
               <Button type="button" variant="outline" size="sm" onClick={addTag}>
-                Add
+                {t("edit.add")}
               </Button>
             </div>
             {tags.length > 0 && (
@@ -145,10 +147,10 @@ export function SkillEditDialog({ skill, onClose, onSave }: SkillEditDialogProps
 
         <DialogFooter>
           <Button variant="outline" onClick={onClose} disabled={loading}>
-            Cancel
+            {t("edit.cancel")}
           </Button>
           <Button onClick={handleSave} disabled={loading || !name.trim()}>
-            {loading ? "Saving..." : "Save"}
+            {loading ? t("edit.saving") : t("edit.save")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/skills/skill-upload-dialog.tsx b/ui/web/src/pages/skills/skill-upload-dialog.tsx
index 78018327..96894ae7 100644
--- a/ui/web/src/pages/skills/skill-upload-dialog.tsx
+++ b/ui/web/src/pages/skills/skill-upload-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useRef } from "react";
+import { useTranslation } from "react-i18next";
 import { Upload } from "lucide-react";
 import {
   Dialog,
@@ -17,6 +18,7 @@ interface SkillUploadDialogProps {
 }
 
 export function SkillUploadDialog({ open, onOpenChange, onUpload }: SkillUploadDialogProps) {
+  const { t } = useTranslation("skills");
   const [file, setFile] = useState<File | null>(null);
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState("");
@@ -32,7 +34,7 @@ export function SkillUploadDialog({ open, onOpenChange, onUpload }: SkillUploadD
       setFile(null);
       onOpenChange(false);
     } catch (err: unknown) {
-      setError(err instanceof Error ? err.message : "Upload failed");
+      setError(err instanceof Error ? err.message : t("upload.uploading"));
     } finally {
       setLoading(false);
     }
@@ -57,7 +59,7 @@ export function SkillUploadDialog({ open, onOpenChange, onUpload }: SkillUploadD
       setFile(dropped);
       setError("");
     } else {
-      setError("Only .zip files are accepted");
+      setError(t("upload.onlyZip"));
     }
   };
 
@@ -65,9 +67,9 @@ export function SkillUploadDialog({ open, onOpenChange, onUpload }: SkillUploadD
     <Dialog open={open} onOpenChange={handleClose}>
       <DialogContent>
         <DialogHeader>
-          <DialogTitle>Upload Skill</DialogTitle>
+          <DialogTitle>{t("upload.title")}</DialogTitle>
           <DialogDescription>
-            Upload a ZIP file containing a SKILL.md at the root with YAML frontmatter (name, description, slug).
+            {t("upload.description")}
           </DialogDescription>
         </DialogHeader>
 
@@ -88,7 +90,7 @@ export function SkillUploadDialog({ open, onOpenChange, onUpload }: SkillUploadD
             <p className="text-sm font-medium">{file.name} ({(file.size / 1024).toFixed(1)} KB)</p>
           ) : (
             <p className="text-sm text-muted-foreground">
-              {dragging ? "Drop .zip file here" : "Click or drag & drop a .zip file"}
+              {dragging ? t("upload.dropHere") : t("upload.dropOrClick")}
             </p>
           )}
           <input
@@ -107,10 +109,10 @@ export function SkillUploadDialog({ open, onOpenChange, onUpload }: SkillUploadD
 
         <DialogFooter>
           <Button variant="outline" onClick={() => handleClose(false)} disabled={loading}>
-            Cancel
+            {t("upload.cancel")}
           </Button>
           <Button onClick={handleSubmit} disabled={!file || loading}>
-            {loading ? "Uploading..." : "Upload"}
+            {loading ? t("upload.uploading") : t("upload.button")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/skills/skills-page.tsx b/ui/web/src/pages/skills/skills-page.tsx
index a23ae09f..c8a1c2fe 100644
--- a/ui/web/src/pages/skills/skills-page.tsx
+++ b/ui/web/src/pages/skills/skills-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Zap, Pencil, RefreshCw, Upload, Trash2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -23,6 +24,7 @@ const visibilityColor: Record<string, string> = {
 };
 
 export function SkillsPage() {
+  const { t } = useTranslation("skills");
   const {
     skills, loading, refresh, getSkill, uploadSkill, updateSkill, deleteSkill,
     getSkillVersions, getSkillFiles, getSkillFileContent,
@@ -71,15 +73,15 @@ export function SkillsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Skills"
-        description="Manage agent skills and capabilities"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex gap-2">
             <Button variant="outline" size="sm" onClick={() => setUploadOpen(true)} className="gap-1">
-              <Upload className="h-3.5 w-3.5" /> Upload
+              <Upload className="h-3.5 w-3.5" /> {t("upload.button")}
             </Button>
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("refresh", { ns: "common" })}
             </Button>
           </div>
         }
@@ -89,7 +91,7 @@ export function SkillsPage() {
         <SearchInput
           value={search}
           onChange={setSearch}
-          placeholder="Search skills..."
+          placeholder={t("searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -100,19 +102,19 @@ export function SkillsPage() {
         ) : filtered.length === 0 ? (
           <EmptyState
             icon={Zap}
-            title={search ? "No matching skills" : "No skills"}
-            description={search ? "Try a different search term." : "No skills have been registered yet."}
+            title={search ? t("noMatchTitle") : t("emptyTitle")}
+            description={search ? t("noMatchDescription") : t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border">
             <table className="w-full text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Name</th>
-                  <th className="px-4 py-3 text-left font-medium">Description</th>
-                  <th className="px-4 py-3 text-left font-medium">Source</th>
-                  <th className="px-4 py-3 text-left font-medium">Visibility</th>
-                  <th className="px-4 py-3 text-right font-medium">Actions</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.name")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.description")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.source")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.visibility")}</th>
+                  <th className="px-4 py-3 text-right font-medium">{t("columns.actions")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -134,7 +136,7 @@ export function SkillsPage() {
                       </div>
                     </td>
                     <td className="max-w-xs truncate px-4 py-3 text-muted-foreground">
-                      {skill.description || "No description"}
+                      {skill.description || t("noDescription")}
                     </td>
                     <td className="px-4 py-3">
                       <Badge variant="outline">{skill.source || "file"}</Badge>
@@ -216,10 +218,10 @@ export function SkillsPage() {
       <ConfirmDeleteDialog
         open={!!deleteTarget}
         onOpenChange={(open) => !open && setDeleteTarget(null)}
-        title="Delete Skill"
-        description={`Are you sure you want to delete "${deleteTarget?.name}"? This action cannot be undone.`}
+        title={t("delete.title")}
+        description={t("delete.description", { name: deleteTarget?.name })}
         confirmValue={deleteTarget?.name || ""}
-        confirmLabel="Delete"
+        confirmLabel={t("delete.confirmLabel")}
         onConfirm={handleDelete}
         loading={deleteLoading}
       />
diff --git a/ui/web/src/pages/storage/storage-page.tsx b/ui/web/src/pages/storage/storage-page.tsx
index f78bf11e..51a17c1c 100644
--- a/ui/web/src/pages/storage/storage-page.tsx
+++ b/ui/web/src/pages/storage/storage-page.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect, useCallback, useMemo } from "react";
 import { RefreshCw } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { PageHeader } from "@/components/shared/page-header";
 import { Button } from "@/components/ui/button";
 import {
@@ -15,6 +16,7 @@ import { FileBrowser } from "@/components/shared/file-browser";
 import { useStorage } from "./hooks/use-storage";
 
 export function StoragePage() {
+  const { t } = useTranslation("storage");
   const { files, totalSize, baseDir, loading, listFiles, readFile, deleteFile } = useStorage();
 
   const [activePath, setActivePath] = useState<string | null>(null);
@@ -66,12 +68,12 @@ export function StoragePage() {
   return (
     <div className="flex flex-col h-full p-4 sm:p-6">
       <PageHeader
-        title="Storage"
-        description={baseDir ? `${baseDir} — ${formatSize(totalSize)}` : "Workspace file browser"}
+        title={t("title")}
+        description={baseDir ? t("descriptionWithPath", { path: baseDir, size: formatSize(totalSize) }) : t("description")}
         actions={
           <Button variant="outline" size="sm" onClick={listFiles} disabled={loading}>
             <RefreshCw className={`h-4 w-4 mr-1.5 ${loading ? "animate-spin" : ""}`} />
-            Refresh
+            {t("common:refresh", "Refresh")}
           </Button>
         }
       />
@@ -93,19 +95,19 @@ export function StoragePage() {
       <Dialog open={!!deleteTarget} onOpenChange={(open) => { if (!open) setDeleteTarget(null); }}>
         <DialogContent>
           <DialogHeader>
-            <DialogTitle>Delete {deleteTarget?.isDir ? "folder" : "file"}</DialogTitle>
+            <DialogTitle>{deleteTarget?.isDir ? t("delete.folderTitle") : t("delete.fileTitle")}</DialogTitle>
             <DialogDescription>
-              Are you sure you want to delete <span className="font-semibold text-foreground">{deleteName}</span>?
-              {deleteTarget?.isDir && " All contents will be removed recursively."}
-              {" "}This action cannot be undone.
+              {t("delete.description", { name: deleteName })}
+              {deleteTarget?.isDir && t("delete.folderWarning")}
+              {t("delete.undone")}
             </DialogDescription>
           </DialogHeader>
           <DialogFooter>
             <Button variant="outline" onClick={() => setDeleteTarget(null)} disabled={deleting}>
-              Cancel
+              {t("common:cancel", "Cancel")}
             </Button>
             <Button variant="destructive" onClick={handleDeleteConfirm} disabled={deleting}>
-              {deleting ? "Deleting..." : "Delete"}
+              {deleting ? t("delete.deleting") : t("delete.confirmLabel")}
             </Button>
           </DialogFooter>
         </DialogContent>
diff --git a/ui/web/src/pages/teams/member-sections/member-list.tsx b/ui/web/src/pages/teams/member-sections/member-list.tsx
index 0043a88e..babef154 100644
--- a/ui/web/src/pages/teams/member-sections/member-list.tsx
+++ b/ui/web/src/pages/teams/member-sections/member-list.tsx
@@ -1,5 +1,6 @@
 import { Users, X } from "lucide-react";
 import { Badge } from "@/components/ui/badge";
+import { useTranslation } from "react-i18next";
 import type { TeamMemberData } from "@/types/team";
 import { roleBadgeVariant } from "./member-utils";
 
@@ -9,11 +10,13 @@ interface MemberListProps {
 }
 
 export function MemberList({ members, onRemove }: MemberListProps) {
+  const { t } = useTranslation("teams");
+
   if (members.length === 0) {
     return (
       <div className="flex flex-col items-center gap-2 py-8 text-center">
         <Users className="h-8 w-8 text-muted-foreground/50" />
-        <p className="text-sm text-muted-foreground">No members</p>
+        <p className="text-sm text-muted-foreground">{t("members.noMembers")}</p>
       </div>
     );
   }
@@ -21,9 +24,9 @@ export function MemberList({ members, onRemove }: MemberListProps) {
   return (
     <div className="rounded-lg border">
       <div className="grid grid-cols-[1fr_1fr_80px_40px] items-center gap-2 border-b bg-muted/50 px-4 py-2.5 text-xs font-medium text-muted-foreground">
-        <span>Agent</span>
-        <span>Frontmatter</span>
-        <span>Role</span>
+        <span>{t("members.columns.agent")}</span>
+        <span>{t("members.columns.frontmatter")}</span>
+        <span>{t("members.columns.role")}</span>
         <span />
       </div>
       {members.map((member) => (
@@ -59,7 +62,7 @@ export function MemberList({ members, onRemove }: MemberListProps) {
                 type="button"
                 onClick={() => onRemove(member.agent_id)}
                 className="rounded p-1 text-muted-foreground/50 transition-colors hover:bg-destructive/10 hover:text-destructive"
-                title="Remove member"
+                title={t("members.removeMember")}
               >
                 <X className="h-4 w-4" />
               </button>
diff --git a/ui/web/src/pages/teams/task-sections/task-detail-dialog.tsx b/ui/web/src/pages/teams/task-sections/task-detail-dialog.tsx
index b9c3bd5d..efb327c2 100644
--- a/ui/web/src/pages/teams/task-sections/task-detail-dialog.tsx
+++ b/ui/web/src/pages/teams/task-sections/task-detail-dialog.tsx
@@ -5,6 +5,7 @@ import {
   DialogTitle,
 } from "@/components/ui/dialog";
 import { Badge } from "@/components/ui/badge";
+import { useTranslation } from "react-i18next";
 import { formatDate } from "@/lib/format";
 import type { TeamTaskData } from "@/types/team";
 import { taskStatusBadgeVariant } from "./task-utils";
@@ -15,45 +16,47 @@ interface TaskDetailDialogProps {
 }
 
 export function TaskDetailDialog({ task, onClose }: TaskDetailDialogProps) {
+  const { t } = useTranslation("teams");
+
   return (
     <Dialog open onOpenChange={() => onClose()}>
       <DialogContent className="max-h-[85vh] w-[95vw] overflow-y-auto sm:max-w-4xl">
         <DialogHeader>
-          <DialogTitle>Task Detail</DialogTitle>
+          <DialogTitle>{t("tasks.detail.title")}</DialogTitle>
         </DialogHeader>
 
         <div className="space-y-4">
           {/* Subject */}
           <div className="rounded-md border p-3">
-            <p className="mb-1 text-xs font-medium text-muted-foreground">Subject</p>
+            <p className="mb-1 text-xs font-medium text-muted-foreground">{t("tasks.detail.subject")}</p>
             <p className="text-sm font-medium">{task.subject}</p>
           </div>
 
           {/* Summary grid */}
           <div className="grid grid-cols-2 gap-3 text-sm">
             <div>
-              <span className="text-muted-foreground">Status:</span>{" "}
+              <span className="text-muted-foreground">{t("tasks.detail.status")}</span>{" "}
               <Badge variant={taskStatusBadgeVariant(task.status)} className="text-xs">
                 {task.status.replace("_", " ")}
               </Badge>
             </div>
             <div>
-              <span className="text-muted-foreground">Priority:</span>{" "}
+              <span className="text-muted-foreground">{t("tasks.detail.priority")}</span>{" "}
               <span className="font-medium">{task.priority}</span>
             </div>
             <div>
-              <span className="text-muted-foreground">Owner:</span>{" "}
+              <span className="text-muted-foreground">{t("tasks.detail.owner")}</span>{" "}
               <span className="font-medium">{task.owner_agent_key || "—"}</span>
             </div>
             {task.created_at && (
               <div>
-                <span className="text-muted-foreground">Created:</span>{" "}
+                <span className="text-muted-foreground">{t("tasks.detail.created")}</span>{" "}
                 {formatDate(task.created_at)}
               </div>
             )}
             {task.updated_at && (
               <div>
-                <span className="text-muted-foreground">Updated:</span>{" "}
+                <span className="text-muted-foreground">{t("tasks.detail.updated")}</span>{" "}
                 {formatDate(task.updated_at)}
               </div>
             )}
@@ -62,7 +65,7 @@ export function TaskDetailDialog({ task, onClose }: TaskDetailDialogProps) {
           {/* Blocked by */}
           {task.blocked_by && task.blocked_by.length > 0 && (
             <div className="text-sm">
-              <span className="text-muted-foreground">Blocked by:</span>{" "}
+              <span className="text-muted-foreground">{t("tasks.detail.blockedBy")}</span>{" "}
               <span className="font-mono text-xs">{task.blocked_by.join(", ")}</span>
             </div>
           )}
@@ -70,7 +73,7 @@ export function TaskDetailDialog({ task, onClose }: TaskDetailDialogProps) {
           {/* Description */}
           {task.description && (
             <div className="rounded-md border p-3">
-              <p className="mb-1 text-xs font-medium text-muted-foreground">Description</p>
+              <p className="mb-1 text-xs font-medium text-muted-foreground">{t("tasks.detail.description")}</p>
               <pre className="whitespace-pre-wrap break-words text-sm">{task.description}</pre>
             </div>
           )}
@@ -78,7 +81,7 @@ export function TaskDetailDialog({ task, onClose }: TaskDetailDialogProps) {
           {/* Result */}
           {task.result && (
             <div className="rounded-md border p-3">
-              <p className="mb-1 text-xs font-medium text-muted-foreground">Result</p>
+              <p className="mb-1 text-xs font-medium text-muted-foreground">{t("tasks.detail.result")}</p>
               <pre className="max-h-[40vh] overflow-y-auto whitespace-pre-wrap break-words text-sm">
                 {task.result}
               </pre>
diff --git a/ui/web/src/pages/teams/task-sections/task-list.tsx b/ui/web/src/pages/teams/task-sections/task-list.tsx
index 85713c06..1e5688ce 100644
--- a/ui/web/src/pages/teams/task-sections/task-list.tsx
+++ b/ui/web/src/pages/teams/task-sections/task-list.tsx
@@ -1,6 +1,7 @@
 import { useState } from "react";
 import { ClipboardList } from "lucide-react";
 import { Badge } from "@/components/ui/badge";
+import { useTranslation } from "react-i18next";
 import type { TeamTaskData } from "@/types/team";
 import { taskStatusBadgeVariant } from "./task-utils";
 import { TaskDetailDialog } from "./task-detail-dialog";
@@ -11,12 +12,13 @@ interface TaskListProps {
 }
 
 export function TaskList({ tasks, loading }: TaskListProps) {
+  const { t } = useTranslation("teams");
   const [selectedTask, setSelectedTask] = useState<TeamTaskData | null>(null);
 
   if (loading && tasks.length === 0) {
     return (
       <div className="py-8 text-center text-sm text-muted-foreground">
-        Loading tasks...
+        {t("tasks.loading")}
       </div>
     );
   }
@@ -25,9 +27,9 @@ export function TaskList({ tasks, loading }: TaskListProps) {
     return (
       <div className="flex flex-col items-center gap-2 py-8 text-center">
         <ClipboardList className="h-8 w-8 text-muted-foreground/50" />
-        <p className="text-sm text-muted-foreground">No tasks yet</p>
+        <p className="text-sm text-muted-foreground">{t("tasks.noTasks")}</p>
         <p className="text-xs text-muted-foreground">
-          Tasks are created by team agents during collaboration.
+          {t("tasks.noTasksDescription")}
         </p>
       </div>
     );
@@ -37,10 +39,10 @@ export function TaskList({ tasks, loading }: TaskListProps) {
     <>
       <div className="overflow-x-auto rounded-lg border">
         <div className="grid min-w-[400px] grid-cols-[1fr_90px_100px_60px] items-center gap-2 border-b bg-muted/50 px-4 py-2.5 text-xs font-medium text-muted-foreground">
-          <span>Subject</span>
-          <span>Status</span>
-          <span>Owner</span>
-          <span>Priority</span>
+          <span>{t("tasks.columns.subject")}</span>
+          <span>{t("tasks.columns.status")}</span>
+          <span>{t("tasks.columns.owner")}</span>
+          <span>{t("tasks.columns.priority")}</span>
         </div>
         {tasks.map((task) => (
           <div
diff --git a/ui/web/src/pages/teams/team-card.tsx b/ui/web/src/pages/teams/team-card.tsx
index 0074135a..47b3503f 100644
--- a/ui/web/src/pages/teams/team-card.tsx
+++ b/ui/web/src/pages/teams/team-card.tsx
@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { Users, Trash2 } from "lucide-react";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
@@ -10,6 +11,7 @@ interface TeamCardProps {
 }
 
 export function TeamCard({ team, onClick, onDelete }: TeamCardProps) {
+  const { t } = useTranslation("teams");
   return (
     <button
       type="button"
@@ -40,7 +42,7 @@ export function TeamCard({ team, onClick, onDelete }: TeamCardProps) {
       <div className="flex items-center gap-1.5">
         {team.lead_agent_key && (
           <Badge variant="outline" className="text-[11px]">
-            Lead: {team.lead_agent_key}
+            {t("settings.leadAgent")}: {team.lead_agent_key}
           </Badge>
         )}
         {onDelete && (
diff --git a/ui/web/src/pages/teams/team-create-dialog.tsx b/ui/web/src/pages/teams/team-create-dialog.tsx
index 8921a1b8..9614bf30 100644
--- a/ui/web/src/pages/teams/team-create-dialog.tsx
+++ b/ui/web/src/pages/teams/team-create-dialog.tsx
@@ -18,6 +18,7 @@ import {
   TooltipProvider,
   TooltipTrigger,
 } from "@/components/ui/tooltip";
+import { useTranslation } from "react-i18next";
 import { useAgents } from "@/pages/agents/hooks/use-agents";
 
 interface TeamCreateDialogProps {
@@ -32,6 +33,7 @@ interface TeamCreateDialogProps {
 }
 
 export function TeamCreateDialog({ open, onOpenChange, onCreate }: TeamCreateDialogProps) {
+  const { t } = useTranslation("teams");
   const { agents, loading: agentsLoading, refresh: refreshAgents } = useAgents();
   const [name, setName] = useState("");
   const [description, setDescription] = useState("");
@@ -112,54 +114,52 @@ export function TeamCreateDialog({ open, onOpenChange, onCreate }: TeamCreateDia
     <Dialog open={open} onOpenChange={onOpenChange}>
       <DialogContent className="max-h-[90vh] flex flex-col">
         <DialogHeader>
-          <DialogTitle>Create Team</DialogTitle>
+          <DialogTitle>{t("create.title")}</DialogTitle>
         </DialogHeader>
         <div className="space-y-4 py-4 px-0.5 -mx-0.5 overflow-y-auto min-h-0">
           <div className="space-y-2">
-            <Label htmlFor="teamName">Name *</Label>
+            <Label htmlFor="teamName">{t("create.name")}</Label>
             <Input
               id="teamName"
               value={name}
               onChange={(e) => setName(e.target.value)}
-              placeholder="e.g. Research Team"
+              placeholder={t("create.namePlaceholder")}
             />
           </div>
 
           <div className="space-y-2">
-            <Label htmlFor="teamDesc">Description</Label>
+            <Label htmlFor="teamDesc">{t("create.description")}</Label>
             <Input
               id="teamDesc"
               value={description}
               onChange={(e) => setDescription(e.target.value)}
-              placeholder="Optional team description..."
+              placeholder={t("create.descriptionPlaceholder")}
             />
           </div>
 
           <div className="space-y-2">
-            <Label>Lead Agent *</Label>
+            <Label>{t("create.leadAgent")}</Label>
             <Combobox
               value={lead}
               onChange={setLead}
               options={leadOptions}
-              placeholder={agentsLoading ? "Loading agents..." : "Select lead agent..."}
+              placeholder={agentsLoading ? t("create.loadingAgents") : t("create.selectLeadAgent")}
             />
             {!agentsLoading && leadOptions.length === 0 && (
-              <p className="text-xs text-muted-foreground">No active agents found. Create agents first.</p>
+              <p className="text-xs text-muted-foreground">{t("create.noActiveAgents")}</p>
             )}
           </div>
 
           <div className="space-y-2">
             <Label className="inline-flex items-center gap-1">
-              Members
+              {t("create.members")}
               <TooltipProvider delayDuration={200}>
                 <Tooltip>
                   <TooltipTrigger asChild>
                     <Info className="h-3.5 w-3.5 text-muted-foreground cursor-help" />
                   </TooltipTrigger>
                   <TooltipContent side="top">
-                    Only predefined agents can be added as team members.
-                    <br />
-                    Open agents are per-user and lack shared context needed for team collaboration.
+                    {t("create.membersTooltip")}
                   </TooltipContent>
                 </Tooltip>
               </TooltipProvider>
@@ -175,7 +175,7 @@ export function TeamCreateDialog({ open, onOpenChange, onCreate }: TeamCreateDia
                 }
               }}
               options={memberOptions}
-              placeholder={agentsLoading ? "Loading agents..." : "Search and add members..."}
+              placeholder={agentsLoading ? t("create.loadingAgents") : t("create.searchMembers")}
             />
             {members.length > 0 && (
               <div className="flex flex-wrap gap-1.5 pt-1">
@@ -197,10 +197,10 @@ export function TeamCreateDialog({ open, onOpenChange, onCreate }: TeamCreateDia
         </div>
         <DialogFooter>
           <Button variant="outline" onClick={() => onOpenChange(false)} disabled={loading}>
-            Cancel
+            {t("create.cancel")}
           </Button>
           <Button onClick={handleCreate} disabled={!name.trim() || !leadOptions.some((o) => o.value === lead) || loading}>
-            {loading ? "Creating..." : "Create"}
+            {loading ? t("create.creating") : t("create.create")}
           </Button>
         </DialogFooter>
       </DialogContent>
diff --git a/ui/web/src/pages/teams/team-delegations-tab.tsx b/ui/web/src/pages/teams/team-delegations-tab.tsx
index 5db6de39..b90073fe 100644
--- a/ui/web/src/pages/teams/team-delegations-tab.tsx
+++ b/ui/web/src/pages/teams/team-delegations-tab.tsx
@@ -4,6 +4,7 @@ import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import { EmptyState } from "@/components/shared/empty-state";
 import { DeferredSpinner } from "@/components/shared/loading-skeleton";
+import { useTranslation } from "react-i18next";
 import { useMinLoading } from "@/hooks/use-min-loading";
 import { formatDate, formatDuration } from "@/lib/format";
 import { useTeamDelegations } from "./hooks/use-team-delegations";
@@ -16,6 +17,7 @@ interface TeamDelegationsTabProps {
 }
 
 export function TeamDelegationsTab({ teamId }: TeamDelegationsTabProps) {
+  const { t } = useTranslation("teams");
   const { records, loading, refresh } = useTeamDelegations(teamId);
   const { getDelegation } = useDelegations();
   const { getTrace } = useTraces();
@@ -28,8 +30,8 @@ export function TeamDelegationsTab({ teamId }: TeamDelegationsTabProps) {
     return (
       <EmptyState
         icon={ArrowRightLeft}
-        title="No delegations"
-        description="No delegation records found for this team."
+        title={t("delegations.noTitle")}
+        description={t("delegations.noDescription")}
       />
     );
   }
@@ -38,18 +40,18 @@ export function TeamDelegationsTab({ teamId }: TeamDelegationsTabProps) {
     <>
       <div className="mb-4 flex justify-end">
         <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-          <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+          <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("delegations.refresh")}
         </Button>
       </div>
       <div className="rounded-md border overflow-x-auto">
         <table className="w-full min-w-[600px] text-sm">
           <thead>
             <tr className="border-b bg-muted/50">
-              <th className="px-4 py-3 text-left font-medium">Source / Target</th>
-              <th className="px-4 py-3 text-left font-medium">Task</th>
-              <th className="px-4 py-3 text-left font-medium">Status</th>
-              <th className="px-4 py-3 text-left font-medium">Duration</th>
-              <th className="px-4 py-3 text-left font-medium">Time</th>
+              <th className="px-4 py-3 text-left font-medium">{t("delegations.columns.sourceTarget")}</th>
+              <th className="px-4 py-3 text-left font-medium">{t("delegations.columns.task")}</th>
+              <th className="px-4 py-3 text-left font-medium">{t("delegations.columns.status")}</th>
+              <th className="px-4 py-3 text-left font-medium">{t("delegations.columns.duration")}</th>
+              <th className="px-4 py-3 text-left font-medium">{t("delegations.columns.time")}</th>
             </tr>
           </thead>
           <tbody>
diff --git a/ui/web/src/pages/teams/team-detail-page.tsx b/ui/web/src/pages/teams/team-detail-page.tsx
index 855fc746..c280fe3d 100644
--- a/ui/web/src/pages/teams/team-detail-page.tsx
+++ b/ui/web/src/pages/teams/team-detail-page.tsx
@@ -5,6 +5,7 @@ import { Badge } from "@/components/ui/badge";
 import { ArrowLeft, Users, Trash2 } from "lucide-react";
 import { DetailPageSkeleton } from "@/components/shared/loading-skeleton";
 import { ConfirmDeleteDialog } from "@/components/shared/confirm-delete-dialog";
+import { useTranslation } from "react-i18next";
 import { useTeams } from "./hooks/use-teams";
 import { TeamMembersTab } from "./team-members-tab";
 import { TeamTasksTab } from "./team-tasks-tab";
@@ -18,6 +19,7 @@ interface TeamDetailPageProps {
 }
 
 export function TeamDetailPage({ teamId, onBack }: TeamDetailPageProps) {
+  const { t } = useTranslation("teams");
   const { getTeam, getTeamTasks, addMember, removeMember, deleteTeam } = useTeams();
   const [team, setTeam] = useState<TeamData | null>(null);
   const [members, setMembers] = useState<TeamMemberData[]>([]);
@@ -88,11 +90,15 @@ export function TeamDetailPage({ teamId, onBack }: TeamDetailPageProps) {
           <div className="mt-1 flex flex-wrap items-center gap-x-2 gap-y-1 text-sm text-muted-foreground">
             {team.lead_agent_key && (
               <>
-                <span>Lead: {team.lead_agent_key}</span>
+                <span>{t("detail.lead")}: {team.lead_agent_key}</span>
                 <span className="text-border">|</span>
               </>
             )}
-            <span>{members.length} member{members.length !== 1 ? "s" : ""}</span>
+            <span>
+              {members.length !== 1
+                ? t("detail.memberCountPlural", { count: members.length })
+                : t("detail.memberCount", { count: members.length })}
+            </span>
           </div>
           {team.description && (
             <p className="mt-1 text-sm text-muted-foreground/70">{team.description}</p>
@@ -112,10 +118,10 @@ export function TeamDetailPage({ teamId, onBack }: TeamDetailPageProps) {
       <div className="max-w-4xl rounded-xl border bg-card p-3 shadow-sm sm:p-4">
         <Tabs value={activeTab} onValueChange={setActiveTab}>
           <TabsList className="w-full justify-start overflow-x-auto overflow-y-hidden">
-            <TabsTrigger value="members">Members</TabsTrigger>
-            <TabsTrigger value="tasks">Tasks</TabsTrigger>
-            <TabsTrigger value="delegations">Delegations</TabsTrigger>
-            <TabsTrigger value="settings">Settings</TabsTrigger>
+            <TabsTrigger value="members">{t("detail.tabs.members")}</TabsTrigger>
+            <TabsTrigger value="tasks">{t("detail.tabs.tasks")}</TabsTrigger>
+            <TabsTrigger value="delegations">{t("detail.tabs.delegations")}</TabsTrigger>
+            <TabsTrigger value="settings">{t("detail.tabs.settings")}</TabsTrigger>
           </TabsList>
 
           <TabsContent value="members" className="mt-4">
@@ -144,10 +150,10 @@ export function TeamDetailPage({ teamId, onBack }: TeamDetailPageProps) {
       <ConfirmDeleteDialog
         open={deleteOpen}
         onOpenChange={setDeleteOpen}
-        title="Delete Team"
-        description={`Are you sure you want to delete "${team.name}"? All members, tasks, and configuration will be permanently removed.`}
+        title={t("delete.title")}
+        description={t("detail.deleteDescription", { name: team.name })}
         confirmValue={team.name}
-        confirmLabel="Delete"
+        confirmLabel={t("delete.confirmLabel")}
         onConfirm={async () => {
           await deleteTeam(teamId);
           setDeleteOpen(false);
diff --git a/ui/web/src/pages/teams/team-members-tab.tsx b/ui/web/src/pages/teams/team-members-tab.tsx
index 6257eb51..cccac857 100644
--- a/ui/web/src/pages/teams/team-members-tab.tsx
+++ b/ui/web/src/pages/teams/team-members-tab.tsx
@@ -9,6 +9,7 @@ import {
   TooltipProvider,
   TooltipTrigger,
 } from "@/components/ui/tooltip";
+import { useTranslation } from "react-i18next";
 import { useAgents } from "@/pages/agents/hooks/use-agents";
 import type { TeamMemberData } from "@/types/team";
 import { MemberList } from "./member-sections";
@@ -21,6 +22,7 @@ interface TeamMembersTabProps {
 }
 
 export function TeamMembersTab({ members, onAddMember, onRemoveMember }: TeamMembersTabProps) {
+  const { t } = useTranslation("teams");
   const { agents, refresh: refreshAgents } = useAgents();
   const [selectedAgent, setSelectedAgent] = useState("");
   const [adding, setAdding] = useState(false);
@@ -57,16 +59,14 @@ export function TeamMembersTab({ members, onAddMember, onRemoveMember }: TeamMem
       {onAddMember && (
         <div className="space-y-2">
           <Label className="inline-flex items-center gap-1">
-            Add Member
+            {t("members.addMember")}
             <TooltipProvider delayDuration={200}>
               <Tooltip>
                 <TooltipTrigger asChild>
                   <Info className="h-3.5 w-3.5 text-muted-foreground cursor-help" />
                 </TooltipTrigger>
                 <TooltipContent side="top">
-                  Only predefined agents can be added as team members.
-                  <br />
-                  Open agents are per-user and lack shared context needed for team collaboration.
+                  {t("members.addMemberTooltip")}
                 </TooltipContent>
               </Tooltip>
             </TooltipProvider>
@@ -77,7 +77,7 @@ export function TeamMembersTab({ members, onAddMember, onRemoveMember }: TeamMem
                 value={selectedAgent}
                 onChange={setSelectedAgent}
                 options={availableAgents}
-                placeholder={availableAgents.length === 0 ? "No available agents" : "Search agents..."}
+                placeholder={availableAgents.length === 0 ? t("members.noAvailableAgents") : t("members.searchAgents")}
               />
             </div>
             <Button
@@ -87,7 +87,7 @@ export function TeamMembersTab({ members, onAddMember, onRemoveMember }: TeamMem
               onClick={handleAdd}
             >
               <UserPlus className="h-4 w-4" />
-              {adding ? "Adding..." : "Add"}
+              {adding ? t("members.adding") : t("members.add")}
             </Button>
           </div>
         </div>
diff --git a/ui/web/src/pages/teams/team-settings-tab.tsx b/ui/web/src/pages/teams/team-settings-tab.tsx
index bb825e97..6c5f95a2 100644
--- a/ui/web/src/pages/teams/team-settings-tab.tsx
+++ b/ui/web/src/pages/teams/team-settings-tab.tsx
@@ -3,6 +3,7 @@ import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { Combobox } from "@/components/ui/combobox";
 import { X, Save, Check } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { CHANNEL_TYPES } from "@/constants/channels";
 import type { TeamData, TeamAccessSettings } from "@/types/team";
 import { useTeams } from "./hooks/use-teams";
@@ -57,6 +58,7 @@ function MultiSelect({
 }
 
 export function TeamSettingsTab({ teamId, team, onSaved }: TeamSettingsTabProps) {
+  const { t } = useTranslation("teams");
   const { updateTeamSettings, getKnownUsers } = useTeams();
   const [knownUsers, setKnownUsers] = useState<string[]>([]);
 
@@ -105,11 +107,11 @@ export function TeamSettingsTab({ teamId, team, onSaved }: TeamSettingsTabProps)
       onSaved();
       setTimeout(() => setSaved(false), 3000);
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to save");
+      setError(err instanceof Error ? err.message : t("settings.failedSave"));
     } finally {
       setSaving(false);
     }
-  }, [teamId, allowUserIds, denyUserIds, allowChannels, denyChannels, progressNotifications, updateTeamSettings, onSaved]);
+  }, [teamId, allowUserIds, denyUserIds, allowChannels, denyChannels, progressNotifications, updateTeamSettings, onSaved, t]);
 
   const userOptions = knownUsers.map((u) => ({ value: u, label: u }));
   const channelOptions = CHANNEL_TYPES.map((c) => ({ value: c.value, label: c.label }));
@@ -118,30 +120,30 @@ export function TeamSettingsTab({ teamId, team, onSaved }: TeamSettingsTabProps)
     <div className="space-y-6">
       {/* User Access Control */}
       <div className="space-y-4">
-        <h3 className="text-sm font-medium">User Access Control</h3>
+        <h3 className="text-sm font-medium">{t("settings.userAccessControl")}</h3>
         <div className="space-y-3 rounded-lg border p-4">
           <div className="space-y-1.5">
-            <label className="text-sm font-medium">Allowed Users</label>
+            <label className="text-sm font-medium">{t("settings.allowedUsers")}</label>
             <p className="text-xs text-muted-foreground">
-              If set, only these users can trigger team workflows. Empty = all allowed.
+              {t("settings.allowedUsersHint")}
             </p>
             <MultiSelect
               options={userOptions}
               selected={allowUserIds}
               onChange={setAllowUserIds}
-              placeholder="Search users..."
+              placeholder={t("settings.searchUsers")}
             />
           </div>
           <div className="space-y-1.5">
-            <label className="text-sm font-medium">Denied Users</label>
+            <label className="text-sm font-medium">{t("settings.deniedUsers")}</label>
             <p className="text-xs text-muted-foreground">
-              Always blocked, overrides allow list.
+              {t("settings.deniedUsersHint")}
             </p>
             <MultiSelect
               options={userOptions}
               selected={denyUserIds}
               onChange={setDenyUserIds}
-              placeholder="Search users..."
+              placeholder={t("settings.searchUsers")}
             />
           </div>
         </div>
@@ -149,30 +151,30 @@ export function TeamSettingsTab({ teamId, team, onSaved }: TeamSettingsTabProps)
 
       {/* Channel Restrictions */}
       <div className="space-y-4">
-        <h3 className="text-sm font-medium">Channel Restrictions</h3>
+        <h3 className="text-sm font-medium">{t("settings.channelRestrictions")}</h3>
         <div className="space-y-3 rounded-lg border p-4">
           <div className="space-y-1.5">
-            <label className="text-sm font-medium">Allowed Channels</label>
+            <label className="text-sm font-medium">{t("settings.allowedChannels")}</label>
             <p className="text-xs text-muted-foreground">
-              If set, only these channels can activate team workflows. Empty = all allowed.
+              {t("settings.allowedChannelsHint")}
             </p>
             <MultiSelect
               options={channelOptions}
               selected={allowChannels}
               onChange={setAllowChannels}
-              placeholder="Select channel..."
+              placeholder={t("settings.selectChannel")}
             />
           </div>
           <div className="space-y-1.5">
-            <label className="text-sm font-medium">Denied Channels</label>
+            <label className="text-sm font-medium">{t("settings.deniedChannels")}</label>
             <p className="text-xs text-muted-foreground">
-              Messages from these channels are always blocked.
+              {t("settings.deniedChannelsHint")}
             </p>
             <MultiSelect
               options={channelOptions}
               selected={denyChannels}
               onChange={setDenyChannels}
-              placeholder="Select channel..."
+              placeholder={t("settings.selectChannel")}
             />
           </div>
         </div>
@@ -180,7 +182,7 @@ export function TeamSettingsTab({ teamId, team, onSaved }: TeamSettingsTabProps)
 
       {/* Notifications */}
       <div className="space-y-4">
-        <h3 className="text-sm font-medium">Notifications</h3>
+        <h3 className="text-sm font-medium">{t("settings.notifications")}</h3>
         <div className="rounded-lg border p-4">
           <label className="flex items-center gap-3 cursor-pointer">
             <input
@@ -190,9 +192,9 @@ export function TeamSettingsTab({ teamId, team, onSaved }: TeamSettingsTabProps)
               className="h-4 w-4 rounded border-input"
             />
             <div>
-              <span className="text-sm font-medium">Progress notifications</span>
+              <span className="text-sm font-medium">{t("settings.progressNotifications")}</span>
               <p className="text-xs text-muted-foreground">
-                Send periodic "Your team is working on it..." messages to chat during async delegations.
+                {t("settings.progressNotificationsHint")}
               </p>
             </div>
           </label>
@@ -203,14 +205,14 @@ export function TeamSettingsTab({ teamId, team, onSaved }: TeamSettingsTabProps)
       <div className="flex items-center gap-3">
         <Button onClick={handleSave} disabled={saving} className="gap-2">
           {saving ? (
-            "Saving..."
+            t("settings.saving")
           ) : saved ? (
             <>
-              <Check className="h-4 w-4" /> Saved
+              <Check className="h-4 w-4" /> {t("settings.saved")}
             </>
           ) : (
             <>
-              <Save className="h-4 w-4" /> Save Settings
+              <Save className="h-4 w-4" /> {t("settings.save")}
             </>
           )}
         </Button>
diff --git a/ui/web/src/pages/teams/team-tasks-tab.tsx b/ui/web/src/pages/teams/team-tasks-tab.tsx
index 57e90a36..00d21f2e 100644
--- a/ui/web/src/pages/teams/team-tasks-tab.tsx
+++ b/ui/web/src/pages/teams/team-tasks-tab.tsx
@@ -1,6 +1,7 @@
 import { useState, useEffect, useCallback } from "react";
 import { Button } from "@/components/ui/button";
 import { RefreshCw } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { useMinLoading } from "@/hooks/use-min-loading";
 import type { TeamTaskData } from "@/types/team";
 import { TaskList } from "./task-sections";
@@ -11,6 +12,7 @@ interface TeamTasksTabProps {
 }
 
 export function TeamTasksTab({ teamId, getTeamTasks }: TeamTasksTabProps) {
+  const { t } = useTranslation("teams");
   const [tasks, setTasks] = useState<TeamTaskData[]>([]);
   const [loading, setLoading] = useState(true);
   const spinning = useMinLoading(loading);
@@ -35,7 +37,7 @@ export function TeamTasksTab({ teamId, getTeamTasks }: TeamTasksTabProps) {
     <div className="space-y-4">
       <div className="flex justify-end">
         <Button variant="outline" size="sm" onClick={load} disabled={spinning} className="gap-1">
-          <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+          <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("tasks.refresh")}
         </Button>
       </div>
       <TaskList tasks={tasks} loading={loading} />
diff --git a/ui/web/src/pages/teams/teams-page.tsx b/ui/web/src/pages/teams/teams-page.tsx
index 76a1e7c5..bd324736 100644
--- a/ui/web/src/pages/teams/teams-page.tsx
+++ b/ui/web/src/pages/teams/teams-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { useParams, useNavigate } from "react-router";
 import { Plus, Users } from "lucide-react";
 import { PageHeader } from "@/components/shared/page-header";
@@ -16,6 +17,8 @@ import { TeamDetailPage } from "./team-detail-page";
 import { usePagination } from "@/hooks/use-pagination";
 
 export function TeamsPage() {
+  const { t } = useTranslation("teams");
+  const { t: tc } = useTranslation("common");
   const { id: detailId } = useParams<{ id: string }>();
   const navigate = useNavigate();
   const { teams, loading, load, createTeam, deleteTeam } = useTeams();
@@ -54,11 +57,11 @@ export function TeamsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Teams"
-        description="Manage your agent teams"
+        title={t("title")}
+        description={t("description")}
         actions={
           <Button onClick={() => setCreateOpen(true)} className="gap-1">
-            <Plus className="h-4 w-4" /> Create Team
+            <Plus className="h-4 w-4" /> {t("createTeam")}
           </Button>
         }
       />
@@ -67,7 +70,7 @@ export function TeamsPage() {
         <SearchInput
           value={search}
           onChange={setSearch}
-          placeholder="Search teams..."
+          placeholder={t("searchPlaceholder")}
           className="max-w-sm"
         />
       </div>
@@ -82,12 +85,8 @@ export function TeamsPage() {
         ) : filtered.length === 0 ? (
           <EmptyState
             icon={Users}
-            title={search ? "No matching teams" : "No teams yet"}
-            description={
-              search
-                ? "Try a different search term."
-                : "Create your first team to get started."
-            }
+            title={search ? t("noMatchTitle") : t("emptyTitle")}
+            description={search ? tc("tryDifferentSearch") : t("emptyDescription")}
           />
         ) : (
           <>
@@ -126,9 +125,9 @@ export function TeamsPage() {
       <ConfirmDialog
         open={!!deleteTarget}
         onOpenChange={() => setDeleteTarget(null)}
-        title="Delete Team"
-        description={`Are you sure you want to delete "${deleteTarget?.name}"? This action cannot be undone.`}
-        confirmLabel="Delete"
+        title={t("delete.title")}
+        description={t("delete.description", { name: deleteTarget?.name })}
+        confirmLabel={t("delete.confirmLabel")}
         variant="destructive"
         onConfirm={async () => {
           if (deleteTarget) {
diff --git a/ui/web/src/pages/traces/trace-detail-dialog.tsx b/ui/web/src/pages/traces/trace-detail-dialog.tsx
index 6b956d53..d0856e09 100644
--- a/ui/web/src/pages/traces/trace-detail-dialog.tsx
+++ b/ui/web/src/pages/traces/trace-detail-dialog.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect, useCallback, useMemo } from "react";
+import { useTranslation } from "react-i18next";
 import {
   Dialog,
   DialogContent,
@@ -49,6 +50,7 @@ interface TraceDetailDialogProps {
 }
 
 export function TraceDetailDialog({ traceId, onClose, getTrace, onNavigateTrace }: TraceDetailDialogProps) {
+  const { t } = useTranslation("traces");
   const [trace, setTrace] = useState<TraceData | null>(null);
   const [spans, setSpans] = useState<SpanData[]>([]);
   const [loading, setLoading] = useState(true);
@@ -110,12 +112,12 @@ export function TraceDetailDialog({ traceId, onClose, getTrace, onNavigateTrace
       <DialogContent className="max-h-[85vh] w-[95vw] overflow-y-auto sm:max-w-6xl">
         <DialogHeader>
           <DialogTitle className="flex items-center gap-2">
-            Trace Detail
+            {t("detail.title")}
             <button
               type="button"
               onClick={() => copy(traceId)}
               className="rounded p-1 text-muted-foreground transition-colors hover:bg-muted hover:text-foreground"
-              title="Copy trace ID"
+              title={t("detail.copyTraceId")}
             >
               {copied ? <Check className="h-3.5 w-3.5 text-green-500" /> : <Copy className="h-3.5 w-3.5" />}
             </button>
@@ -127,49 +129,49 @@ export function TraceDetailDialog({ traceId, onClose, getTrace, onNavigateTrace
             <div className="h-6 w-6 animate-spin rounded-full border-2 border-muted-foreground border-t-transparent" />
           </div>
         ) : !trace ? (
-          <p className="py-8 text-center text-sm text-muted-foreground">Trace not found.</p>
+          <p className="py-8 text-center text-sm text-muted-foreground">{t("detail.notFound")}</p>
         ) : (
           <div className="space-y-4">
             {/* Trace summary */}
             <div className="grid grid-cols-2 gap-3 text-sm sm:grid-cols-4">
               <div>
-                <span className="text-muted-foreground">Name:</span>{" "}
-                <span className="font-medium">{trace.name || "Unnamed"}</span>
+                <span className="text-muted-foreground">{t("detail.name")}</span>{" "}
+                <span className="font-medium">{trace.name || t("unnamed")}</span>
               </div>
               <div>
-                <span className="text-muted-foreground">Status:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.status")}</span>{" "}
                 <StatusBadge status={trace.status} />
               </div>
               <div>
-                <span className="text-muted-foreground">Duration:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.duration")}</span>{" "}
                 {formatDuration(trace.duration_ms || computeDurationMs(trace.start_time, trace.end_time))}
               </div>
               <div>
-                <span className="text-muted-foreground">Channel:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.channel")}</span>{" "}
                 {trace.channel || "—"}
               </div>
               <div>
-                <span className="text-muted-foreground">Tokens:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.tokens")}</span>{" "}
                 {formatTokens(trace.total_input_tokens)} in / {formatTokens(trace.total_output_tokens)} out
                 {((trace.metadata?.total_cache_read_tokens ?? 0) > 0 || (trace.metadata?.total_cache_creation_tokens ?? 0) > 0) && (
                   <span className="ml-1 text-xs">
                     {(trace.metadata?.total_cache_read_tokens ?? 0) > 0 && (
-                      <span className="text-green-400">{formatTokens(trace.metadata!.total_cache_read_tokens!)} cached</span>
+                      <span className="text-green-400">{formatTokens(trace.metadata!.total_cache_read_tokens!)} {t("span.cached")}</span>
                     )}
                   </span>
                 )}
               </div>
               <div>
-                <span className="text-muted-foreground">Spans:</span>{" "}
-                {trace.span_count} ({trace.llm_call_count} LLM, {trace.tool_call_count} tool)
+                <span className="text-muted-foreground">{t("detail.spans")}</span>{" "}
+                {trace.span_count} ({trace.llm_call_count} {t("detail.llmCalls")}, {trace.tool_call_count} {t("detail.toolCalls")})
               </div>
               <div>
-                <span className="text-muted-foreground">Started:</span>{" "}
+                <span className="text-muted-foreground">{t("detail.started")}</span>{" "}
                 {formatDate(trace.start_time)}
               </div>
               {trace.parent_trace_id && (
                 <div>
-                  <span className="text-muted-foreground">Delegated from:</span>{" "}
+                  <span className="text-muted-foreground">{t("detail.delegatedFrom")}</span>{" "}
                   <button
                     type="button"
                     className="cursor-pointer font-mono text-xs text-primary hover:underline"
@@ -183,14 +185,14 @@ export function TraceDetailDialog({ traceId, onClose, getTrace, onNavigateTrace
 
             {trace.input_preview && (
               <div className="rounded-md border p-3">
-                <p className="mb-1 text-xs font-medium text-muted-foreground">Input</p>
+                <p className="mb-1 text-xs font-medium text-muted-foreground">{t("detail.input")}</p>
                 <pre className="max-h-[20vh] overflow-y-auto whitespace-pre-wrap break-all text-sm">{trace.input_preview}</pre>
               </div>
             )}
 
             {trace.output_preview && (
               <div className="rounded-md border p-3">
-                <p className="mb-1 text-xs font-medium text-muted-foreground">Output</p>
+                <p className="mb-1 text-xs font-medium text-muted-foreground">{t("detail.output")}</p>
                 <pre className="max-h-[20vh] overflow-y-auto whitespace-pre-wrap break-all text-sm">{trace.output_preview}</pre>
               </div>
             )}
@@ -204,7 +206,7 @@ export function TraceDetailDialog({ traceId, onClose, getTrace, onNavigateTrace
             {/* Span tree */}
             {spans.length > 0 && (
               <div>
-                <h4 className="mb-2 text-sm font-medium">Spans ({spans.length})</h4>
+                <h4 className="mb-2 text-sm font-medium">{t("detail.spansCount", { count: spans.length })}</h4>
                 <div className="space-y-1">
                   {spanTree.map((node) => (
                     <SpanTreeNode key={node.span.id} node={node} depth={0} />
@@ -220,6 +222,7 @@ export function TraceDetailDialog({ traceId, onClose, getTrace, onNavigateTrace
 }
 
 function SpanTreeNode({ node, depth }: { node: SpanNode; depth: number }) {
+  const { t } = useTranslation("traces");
   const [expanded, setExpanded] = useState(depth === 0);
   const [detailOpen, setDetailOpen] = useState(false);
   const { span, children } = node;
@@ -265,13 +268,13 @@ function SpanTreeNode({ node, depth }: { node: SpanNode; depth: number }) {
               <span className="hidden shrink-0 text-xs text-muted-foreground sm:inline">
                 {formatTokens(span.input_tokens)}/{formatTokens(span.output_tokens)}
                 {(span.metadata?.cache_read_tokens ?? 0) > 0 && (
-                  <span className="ml-1 text-green-400" title="Cached tokens read">
-                    ({formatTokens(span.metadata!.cache_read_tokens!)} cached)
+                  <span className="ml-1 text-green-400">
+                    ({formatTokens(span.metadata!.cache_read_tokens!)} {t("span.cached")})
                   </span>
                 )}
                 {(span.metadata?.thinking_tokens ?? 0) > 0 && (
-                  <span className="ml-1 text-purple-400" title="Thinking tokens">
-                    ({formatTokens(span.metadata!.thinking_tokens!)} thinking)
+                  <span className="ml-1 text-purple-400">
+                    ({formatTokens(span.metadata!.thinking_tokens!)} {t("span.thinking")})
                   </span>
                 )}
               </span>
@@ -288,35 +291,35 @@ function SpanTreeNode({ node, depth }: { node: SpanNode; depth: number }) {
           <div className="max-h-[50vh] space-y-2 overflow-y-auto border-t px-3 py-2">
             {span.model && (
               <div className="text-xs">
-                <span className="text-muted-foreground">Model:</span> {span.provider}/{span.model}
+                <span className="text-muted-foreground">{t("span.model")}</span> {span.provider}/{span.model}
               </div>
             )}
             {(span.input_tokens > 0 || span.output_tokens > 0) && (
               <div className="text-xs">
-                <span className="text-muted-foreground">Tokens:</span>{" "}
+                <span className="text-muted-foreground">{t("span.tokens")}</span>{" "}
                 {formatTokens(span.input_tokens)} in / {formatTokens(span.output_tokens)} out
                 {((span.metadata?.cache_creation_tokens ?? 0) > 0 || (span.metadata?.cache_read_tokens ?? 0) > 0) && (
                   <span className="ml-2 text-muted-foreground">
                     (cache:
                     {(span.metadata?.cache_read_tokens ?? 0) > 0 && (
-                      <span className="ml-1 text-green-400">{formatTokens(span.metadata!.cache_read_tokens!)} read</span>
+                      <span className="ml-1 text-green-400">{formatTokens(span.metadata!.cache_read_tokens!)} {t("span.cacheRead")}</span>
                     )}
                     {(span.metadata?.cache_creation_tokens ?? 0) > 0 && (
-                      <span className="ml-1 text-yellow-400">{formatTokens(span.metadata!.cache_creation_tokens!)} write</span>
+                      <span className="ml-1 text-yellow-400">{formatTokens(span.metadata!.cache_creation_tokens!)} {t("span.cacheWrite")}</span>
                     )}
                     )
                   </span>
                 )}
                 {(span.metadata?.thinking_tokens ?? 0) > 0 && (
                   <span className="ml-2 text-muted-foreground">
-                    (<span className="text-purple-400">{formatTokens(span.metadata!.thinking_tokens!)} thinking</span>)
+                    (<span className="text-purple-400">{formatTokens(span.metadata!.thinking_tokens!)} {t("span.thinking")}</span>)
                   </span>
                 )}
               </div>
             )}
             {span.input_preview && (
               <div>
-                <p className="text-xs text-muted-foreground">Input:</p>
+                <p className="text-xs text-muted-foreground">{t("span.input")}</p>
                 <pre className="mt-1 max-h-[20vh] overflow-y-auto break-all whitespace-pre-wrap rounded bg-muted/50 p-2 text-xs">
                   {span.input_preview}
                 </pre>
@@ -324,7 +327,7 @@ function SpanTreeNode({ node, depth }: { node: SpanNode; depth: number }) {
             )}
             {span.output_preview && (
               <div>
-                <p className="text-xs text-muted-foreground">Output:</p>
+                <p className="text-xs text-muted-foreground">{t("span.output")}</p>
                 <pre className="mt-1 max-h-[20vh] overflow-y-auto break-all whitespace-pre-wrap rounded bg-muted/50 p-2 text-xs">
                   {span.output_preview}
                 </pre>
diff --git a/ui/web/src/pages/traces/traces-page.tsx b/ui/web/src/pages/traces/traces-page.tsx
index cf7fb399..9cc1a73a 100644
--- a/ui/web/src/pages/traces/traces-page.tsx
+++ b/ui/web/src/pages/traces/traces-page.tsx
@@ -1,4 +1,5 @@
 import { useState } from "react";
+import { useTranslation } from "react-i18next";
 import { Activity, GitFork, RefreshCw, Search } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
@@ -14,6 +15,8 @@ import { useMinLoading } from "@/hooks/use-min-loading";
 import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 
 export function TracesPage() {
+  const { t } = useTranslation("traces");
+  const { t: tc } = useTranslation("common");
   const [agentFilter, setAgentFilter] = useState("");
   const [appliedAgentFilter, setAppliedAgentFilter] = useState("");
   const [selectedTraceId, setSelectedTraceId] = useState<string | null>(null);
@@ -39,11 +42,11 @@ export function TracesPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Traces"
-        description="LLM call traces and performance data"
+        title={t("title")}
+        description={t("description")}
         actions={
           <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
           </Button>
         }
       />
@@ -54,12 +57,12 @@ export function TracesPage() {
           <Input
             value={agentFilter}
             onChange={(e) => setAgentFilter(e.target.value)}
-            placeholder="Filter by agent ID..."
+            placeholder={t("filterPlaceholder")}
             className="pl-9"
           />
         </div>
         <Button type="submit" variant="outline" size="sm">
-          Filter
+          {t("filter")}
         </Button>
       </form>
 
@@ -69,20 +72,20 @@ export function TracesPage() {
         ) : traces.length === 0 ? (
           <EmptyState
             icon={Activity}
-            title="No traces"
-            description="No traces found. Traces are recorded when agents process requests."
+            title={t("emptyTitle")}
+            description={t("emptyDescription")}
           />
         ) : (
           <div className="rounded-md border overflow-x-auto">
             <table className="w-full min-w-[700px] text-sm">
               <thead>
                 <tr className="border-b bg-muted/50">
-                  <th className="px-4 py-3 text-left font-medium">Name</th>
-                  <th className="px-4 py-3 text-left font-medium">Status</th>
-                  <th className="px-4 py-3 text-left font-medium">Duration</th>
-                  <th className="px-4 py-3 text-left font-medium">Tokens</th>
-                  <th className="px-4 py-3 text-left font-medium">Spans</th>
-                  <th className="px-4 py-3 text-left font-medium">Time</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.name")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.status")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.duration")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.tokens")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.spans")}</th>
+                  <th className="px-4 py-3 text-left font-medium">{t("columns.time")}</th>
                 </tr>
               </thead>
               <tbody>
@@ -96,7 +99,7 @@ export function TracesPage() {
                       {trace.parent_trace_id && (
                         <GitFork className="mr-1.5 inline-block h-3.5 w-3.5 text-muted-foreground" />
                       )}
-                      {trace.name || "Unnamed"}
+                      {trace.name || t("unnamed")}
                       {trace.channel && (
                         <Badge variant="outline" className="ml-2 text-xs">
                           {trace.channel}
@@ -113,7 +116,7 @@ export function TracesPage() {
                       <div>{formatTokens(trace.total_input_tokens)} / {formatTokens(trace.total_output_tokens)}</div>
                       {(trace.metadata?.total_cache_read_tokens ?? 0) > 0 && (
                         <div className="text-xs text-green-400">
-                          {formatTokens(trace.metadata!.total_cache_read_tokens!)} cached
+                          {formatTokens(trace.metadata!.total_cache_read_tokens!)} {t("cached")}
                         </div>
                       )}
                     </td>
diff --git a/ui/web/src/pages/tts/tts-page.tsx b/ui/web/src/pages/tts/tts-page.tsx
index 1de4a6e5..db8bdf04 100644
--- a/ui/web/src/pages/tts/tts-page.tsx
+++ b/ui/web/src/pages/tts/tts-page.tsx
@@ -1,4 +1,5 @@
 import { useState, useEffect } from "react";
+import { useTranslation } from "react-i18next";
 import { Volume2, RefreshCw, Save } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -12,27 +13,13 @@ import { useTtsConfig, type TtsConfig, type TtsProviderConfig } from "./hooks/us
 import { useMinLoading } from "@/hooks/use-min-loading";
 import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 
-const PROVIDERS = [
-  { value: "", label: "None (Disabled)" },
-  { value: "openai", label: "OpenAI" },
-  { value: "elevenlabs", label: "ElevenLabs" },
-  { value: "edge", label: "Edge (Free)" },
-  { value: "minimax", label: "MiniMax" },
-];
-
-const AUTO_MODES = [
-  { value: "off", label: "Off", desc: "Agent can use TTS tool manually" },
-  { value: "always", label: "Always", desc: "All replies get audio" },
-  { value: "inbound", label: "Inbound", desc: "Only when user sends voice/audio" },
-  { value: "tagged", label: "Tagged", desc: "Only when reply contains [[tts]] tag" },
-];
-
-const REPLY_MODES = [
-  { value: "final", label: "Final only", desc: "Only final replies" },
-  { value: "all", label: "All", desc: "All replies including tool/block" },
-];
+const PROVIDER_VALUES = ["", "openai", "elevenlabs", "edge", "minimax"] as const;
+const AUTO_MODE_VALUES = ["off", "always", "inbound", "tagged"] as const;
+const REPLY_MODE_VALUES = ["final", "all"] as const;
 
 export function TtsPage() {
+  const { t } = useTranslation("tts");
+  const { t: tc } = useTranslation("common");
   const { tts, loading, saving, error, refresh, save } = useTtsConfig();
   const spinning = useMinLoading(loading);
 
@@ -63,7 +50,7 @@ export function TtsPage() {
   if (showSkeleton) {
     return (
       <div className="p-4 sm:p-6">
-        <PageHeader title="Text-to-Speech" description="Configure TTS providers and auto-apply settings" />
+        <PageHeader title={t("title")} description={t("description")} />
         <div className="mt-4">
           <TableSkeleton rows={3} />
         </div>
@@ -74,15 +61,15 @@ export function TtsPage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Text-to-Speech"
-        description="Configure TTS providers and auto-apply settings"
+        title={t("title")}
+        description={t("description")}
         actions={
           <div className="flex gap-2">
             <Button variant="outline" size="sm" onClick={refresh} disabled={spinning} className="gap-1">
-              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+              <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {tc("refresh")}
             </Button>
             <Button size="sm" onClick={handleSave} disabled={!dirty || saving} className="gap-1">
-              <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save"}
+              <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("save")}
             </Button>
           </div>
         }
@@ -93,15 +80,15 @@ export function TtsPage() {
         <CardHeader className="pb-3">
           <div className="flex items-center gap-2">
             <Volume2 className="h-5 w-5" />
-            <CardTitle className="text-base">Status</CardTitle>
+            <CardTitle className="text-base">{t("status.title")}</CardTitle>
             <Badge variant={draft.provider ? "default" : "secondary"}>
-              {draft.provider ? "Configured" : "Disabled"}
+              {draft.provider ? t("status.configured") : t("status.disabled")}
             </Badge>
           </div>
           <CardDescription>
             {draft.provider
-              ? `Primary provider: ${draft.provider}, Auto: ${draft.auto}`
-              : "No TTS provider configured"}
+              ? t("status.activeProvider", { provider: draft.provider, auto: draft.auto })
+              : t("status.noProvider")}
           </CardDescription>
         </CardHeader>
       </Card>
@@ -109,22 +96,22 @@ export function TtsPage() {
       {/* General Settings */}
       <Card className="mt-4">
         <CardHeader className="pb-3">
-          <CardTitle className="text-base">General Settings</CardTitle>
+          <CardTitle className="text-base">{t("general.title")}</CardTitle>
         </CardHeader>
         <CardContent className="space-y-4">
           {/* Provider */}
           <div className="grid gap-1.5">
-            <Label>Primary Provider</Label>
+            <Label>{t("general.primaryProvider")}</Label>
             <div className="flex flex-wrap gap-2">
-              {PROVIDERS.map((p) => (
+              {PROVIDER_VALUES.map((v) => (
                 <Button
-                  key={p.value}
+                  key={v}
                   type="button"
-                  variant={draft.provider === p.value ? "default" : "outline"}
+                  variant={draft.provider === v ? "default" : "outline"}
                   size="sm"
-                  onClick={() => update({ provider: p.value })}
+                  onClick={() => update({ provider: v })}
                 >
-                  {p.label}
+                  {t(`providers.${v || "none"}`)}
                 </Button>
               ))}
             </div>
@@ -132,40 +119,40 @@ export function TtsPage() {
 
           {/* Auto mode */}
           <div className="grid gap-1.5">
-            <Label>Auto-Apply Mode</Label>
+            <Label>{t("general.autoApplyMode")}</Label>
             <div className="flex flex-wrap gap-2">
-              {AUTO_MODES.map((m) => (
+              {AUTO_MODE_VALUES.map((v) => (
                 <Button
-                  key={m.value}
+                  key={v}
                   type="button"
-                  variant={draft.auto === m.value ? "default" : "outline"}
+                  variant={draft.auto === v ? "default" : "outline"}
                   size="sm"
-                  onClick={() => update({ auto: m.value })}
-                  title={m.desc}
+                  onClick={() => update({ auto: v })}
+                  title={t(`autoModes.${v}Desc`)}
                 >
-                  {m.label}
+                  {t(`autoModes.${v}`)}
                 </Button>
               ))}
             </div>
             <p className="text-xs text-muted-foreground">
-              {AUTO_MODES.find((m) => m.value === draft.auto)?.desc}
+              {t(`autoModes.${draft.auto}Desc`)}
             </p>
           </div>
 
           {/* Reply mode */}
           <div className="grid gap-1.5">
-            <Label>Reply Mode</Label>
+            <Label>{t("general.replyMode")}</Label>
             <div className="flex gap-2">
-              {REPLY_MODES.map((m) => (
+              {REPLY_MODE_VALUES.map((v) => (
                 <Button
-                  key={m.value}
+                  key={v}
                   type="button"
-                  variant={draft.mode === m.value ? "default" : "outline"}
+                  variant={draft.mode === v ? "default" : "outline"}
                   size="sm"
-                  onClick={() => update({ mode: m.value })}
-                  title={m.desc}
+                  onClick={() => update({ mode: v })}
+                  title={t(`replyModes.${v}Desc`)}
                 >
-                  {m.label}
+                  {t(`replyModes.${v}`)}
                 </Button>
               ))}
             </div>
@@ -174,7 +161,7 @@ export function TtsPage() {
           {/* Max length & timeout */}
           <div className="grid grid-cols-2 gap-4">
             <div className="grid gap-1.5">
-              <Label htmlFor="tts-maxlen">Max Text Length</Label>
+              <Label htmlFor="tts-maxlen">{t("general.maxTextLength")}</Label>
               <Input
                 id="tts-maxlen"
                 type="number"
@@ -184,7 +171,7 @@ export function TtsPage() {
               />
             </div>
             <div className="grid gap-1.5">
-              <Label htmlFor="tts-timeout">Timeout (ms)</Label>
+              <Label htmlFor="tts-timeout">{t("general.timeout")}</Label>
               <Input
                 id="tts-timeout"
                 type="number"
@@ -202,27 +189,27 @@ export function TtsPage() {
         <Card className="mt-4">
           <CardHeader className="pb-3">
             <CardTitle className="text-base">
-              {PROVIDERS.find((p) => p.value === draft.provider)?.label} Settings
+              {t("providerSettings", { provider: t(`providers.${draft.provider}`) })}
             </CardTitle>
           </CardHeader>
           <CardContent className="space-y-4">
             {draft.provider === "openai" && (
               <>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="oai-key">API Key</Label>
+                  <Label htmlFor="oai-key">{t("openai.apiKey")}</Label>
                   <Input id="oai-key" type="password" value={draft.openai.api_key ?? ""} onChange={(e) => updateProvider("openai", { api_key: e.target.value })} placeholder="sk-..." />
                 </div>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="oai-base">API Base URL</Label>
+                  <Label htmlFor="oai-base">{t("openai.apiBase")}</Label>
                   <Input id="oai-base" value={draft.openai.api_base ?? ""} onChange={(e) => updateProvider("openai", { api_base: e.target.value })} placeholder="https://api.openai.com/v1" />
                 </div>
                 <div className="grid grid-cols-2 gap-4">
                   <div className="grid gap-1.5">
-                    <Label htmlFor="oai-model">Model</Label>
+                    <Label htmlFor="oai-model">{t("openai.model")}</Label>
                     <Input id="oai-model" value={draft.openai.model ?? ""} onChange={(e) => updateProvider("openai", { model: e.target.value })} placeholder="gpt-4o-mini-tts" />
                   </div>
                   <div className="grid gap-1.5">
-                    <Label htmlFor="oai-voice">Voice</Label>
+                    <Label htmlFor="oai-voice">{t("openai.voice")}</Label>
                     <Input id="oai-voice" value={draft.openai.voice ?? ""} onChange={(e) => updateProvider("openai", { voice: e.target.value })} placeholder="alloy" />
                   </div>
                 </div>
@@ -232,20 +219,20 @@ export function TtsPage() {
             {draft.provider === "elevenlabs" && (
               <>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="el-key">API Key</Label>
+                  <Label htmlFor="el-key">{t("elevenlabs.apiKey")}</Label>
                   <Input id="el-key" type="password" value={draft.elevenlabs.api_key ?? ""} onChange={(e) => updateProvider("elevenlabs", { api_key: e.target.value })} placeholder="xi-..." />
                 </div>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="el-base">Base URL</Label>
+                  <Label htmlFor="el-base">{t("elevenlabs.baseUrl")}</Label>
                   <Input id="el-base" value={draft.elevenlabs.base_url ?? ""} onChange={(e) => updateProvider("elevenlabs", { base_url: e.target.value })} placeholder="https://api.elevenlabs.io" />
                 </div>
                 <div className="grid grid-cols-2 gap-4">
                   <div className="grid gap-1.5">
-                    <Label htmlFor="el-voice">Voice ID</Label>
+                    <Label htmlFor="el-voice">{t("elevenlabs.voiceId")}</Label>
                     <Input id="el-voice" value={draft.elevenlabs.voice_id ?? ""} onChange={(e) => updateProvider("elevenlabs", { voice_id: e.target.value })} placeholder="pMsXgVXv3BLzUgSXRplE" />
                   </div>
                   <div className="grid gap-1.5">
-                    <Label htmlFor="el-model">Model ID</Label>
+                    <Label htmlFor="el-model">{t("elevenlabs.modelId")}</Label>
                     <Input id="el-model" value={draft.elevenlabs.model_id ?? ""} onChange={(e) => updateProvider("elevenlabs", { model_id: e.target.value })} placeholder="eleven_multilingual_v2" />
                   </div>
                 </div>
@@ -255,38 +242,38 @@ export function TtsPage() {
             {draft.provider === "edge" && (
               <>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="edge-voice">Voice</Label>
+                  <Label htmlFor="edge-voice">{t("edge.voice")}</Label>
                   <Input id="edge-voice" value={draft.edge.voice ?? ""} onChange={(e) => updateProvider("edge", { voice: e.target.value })} placeholder="en-US-MichelleNeural" />
                 </div>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="edge-rate">Speech Rate</Label>
+                  <Label htmlFor="edge-rate">{t("edge.speechRate")}</Label>
                   <Input id="edge-rate" value={draft.edge.rate ?? ""} onChange={(e) => updateProvider("edge", { rate: e.target.value })} placeholder="+0%" />
                 </div>
-                <p className="text-xs text-muted-foreground">Edge TTS is free and requires no API key. Install with: pip install edge-tts</p>
+                <p className="text-xs text-muted-foreground">{t("edge.hint")}</p>
               </>
             )}
 
             {draft.provider === "minimax" && (
               <>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="mm-key">API Key</Label>
+                  <Label htmlFor="mm-key">{t("minimax.apiKey")}</Label>
                   <Input id="mm-key" type="password" value={draft.minimax.api_key ?? ""} onChange={(e) => updateProvider("minimax", { api_key: e.target.value })} />
                 </div>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="mm-group">Group ID *</Label>
-                  <Input id="mm-group" value={draft.minimax.group_id ?? ""} onChange={(e) => updateProvider("minimax", { group_id: e.target.value })} placeholder="Required for MiniMax" />
+                  <Label htmlFor="mm-group">{t("minimax.groupId")}</Label>
+                  <Input id="mm-group" value={draft.minimax.group_id ?? ""} onChange={(e) => updateProvider("minimax", { group_id: e.target.value })} placeholder={t("minimax.groupIdPlaceholder")} />
                 </div>
                 <div className="grid gap-1.5">
-                  <Label htmlFor="mm-base">API Base</Label>
+                  <Label htmlFor="mm-base">{t("minimax.apiBase")}</Label>
                   <Input id="mm-base" value={draft.minimax.api_base ?? ""} onChange={(e) => updateProvider("minimax", { api_base: e.target.value })} placeholder="https://api.minimax.io/v1" />
                 </div>
                 <div className="grid grid-cols-2 gap-4">
                   <div className="grid gap-1.5">
-                    <Label htmlFor="mm-model">Model</Label>
+                    <Label htmlFor="mm-model">{t("minimax.model")}</Label>
                     <Input id="mm-model" value={draft.minimax.model ?? ""} onChange={(e) => updateProvider("minimax", { model: e.target.value })} placeholder="speech-02-hd" />
                   </div>
                   <div className="grid gap-1.5">
-                    <Label htmlFor="mm-voice">Voice ID</Label>
+                    <Label htmlFor="mm-voice">{t("minimax.voiceId")}</Label>
                     <Input id="mm-voice" value={draft.minimax.voice_id ?? ""} onChange={(e) => updateProvider("minimax", { voice_id: e.target.value })} placeholder="Wise_Woman" />
                   </div>
                 </div>
@@ -303,7 +290,7 @@ export function TtsPage() {
       {dirty && (
         <div className="flex justify-end">
           <Button onClick={handleSave} disabled={saving} className="gap-1">
-            <Save className="h-3.5 w-3.5" /> {saving ? "Saving..." : "Save Changes"}
+            <Save className="h-3.5 w-3.5" /> {saving ? t("saving") : t("saveChanges")}
           </Button>
         </div>
       )}
diff --git a/ui/web/src/pages/usage/usage-page.tsx b/ui/web/src/pages/usage/usage-page.tsx
index e6042f26..fe09962b 100644
--- a/ui/web/src/pages/usage/usage-page.tsx
+++ b/ui/web/src/pages/usage/usage-page.tsx
@@ -1,5 +1,6 @@
 import { useState, useEffect } from "react";
 import { BarChart3, RefreshCw } from "lucide-react";
+import { useTranslation } from "react-i18next";
 import { Button } from "@/components/ui/button";
 import { Badge } from "@/components/ui/badge";
 import { PageHeader } from "@/components/shared/page-header";
@@ -12,6 +13,7 @@ import { useMinLoading } from "@/hooks/use-min-loading";
 import { useDeferredLoading } from "@/hooks/use-deferred-loading";
 
 export function UsagePage() {
+  const { t } = useTranslation("usage");
   const { records, total, summary, loading, loadRecords, loadSummary } = useUsage();
   const spinning = useMinLoading(loading);
   const showSkeleton = useDeferredLoading(loading && records.length === 0);
@@ -38,11 +40,11 @@ export function UsagePage() {
   return (
     <div className="p-4 sm:p-6">
       <PageHeader
-        title="Usage"
-        description="Token usage and costs by agent"
+        title={t("title")}
+        description={t("description")}
         actions={
           <Button variant="outline" size="sm" onClick={handleRefresh} disabled={spinning} className="gap-1">
-            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> Refresh
+            <RefreshCw className={"h-3.5 w-3.5" + (spinning ? " animate-spin" : "")} /> {t("common:refresh", "Refresh")}
           </Button>
         }
       />
@@ -60,19 +62,19 @@ export function UsagePage() {
                 <div key={agentId} className="rounded-lg border p-4">
                   <div className="flex items-center justify-between">
                     <h4 className="text-sm font-medium">{agentId}</h4>
-                    <Badge variant="secondary">{data.sessions} sessions</Badge>
+                    <Badge variant="secondary">{t("summary.sessions", { count: data.sessions })}</Badge>
                   </div>
                   <div className="mt-3 space-y-1 text-sm text-muted-foreground">
                     <div className="flex justify-between">
-                      <span>Input tokens</span>
+                      <span>{t("summary.inputTokens")}</span>
                       <span className="font-medium text-foreground">{formatTokens(data.inputTokens)}</span>
                     </div>
                     <div className="flex justify-between">
-                      <span>Output tokens</span>
+                      <span>{t("summary.outputTokens")}</span>
                       <span className="font-medium text-foreground">{formatTokens(data.outputTokens)}</span>
                     </div>
                     <div className="flex justify-between border-t pt-1">
-                      <span>Total</span>
+                      <span>{t("summary.total")}</span>
                       <span className="font-medium text-foreground">{formatTokens(data.totalTokens)}</span>
                     </div>
                   </div>
@@ -83,24 +85,24 @@ export function UsagePage() {
 
           {/* Recent records table */}
           <div className="mt-6">
-            <h3 className="mb-3 text-sm font-medium">Recent Records</h3>
+            <h3 className="mb-3 text-sm font-medium">{t("recentRecords")}</h3>
             {records.length === 0 ? (
               <EmptyState
                 icon={BarChart3}
-                title="No usage data"
-                description="Usage data will appear here after agents process requests."
+                title={t("emptyTitle")}
+                description={t("emptyDescription")}
               />
             ) : (
               <div className="rounded-md border">
                 <table className="w-full text-sm">
                   <thead>
                     <tr className="border-b bg-muted/50">
-                      <th className="px-4 py-3 text-left font-medium">Agent</th>
-                      <th className="px-4 py-3 text-left font-medium">Model</th>
-                      <th className="px-4 py-3 text-left font-medium">Provider</th>
-                      <th className="px-4 py-3 text-right font-medium">Input</th>
-                      <th className="px-4 py-3 text-right font-medium">Output</th>
-                      <th className="px-4 py-3 text-right font-medium">Total</th>
+                      <th className="px-4 py-3 text-left font-medium">{t("columns.agent")}</th>
+                      <th className="px-4 py-3 text-left font-medium">{t("columns.model")}</th>
+                      <th className="px-4 py-3 text-left font-medium">{t("columns.provider")}</th>
+                      <th className="px-4 py-3 text-right font-medium">{t("columns.input")}</th>
+                      <th className="px-4 py-3 text-right font-medium">{t("columns.output")}</th>
+                      <th className="px-4 py-3 text-right font-medium">{t("columns.total")}</th>
                     </tr>
                   </thead>
                   <tbody>
diff --git a/ui/web/src/stores/use-ui-store.ts b/ui/web/src/stores/use-ui-store.ts
index 0355eb74..5f88003f 100644
--- a/ui/web/src/stores/use-ui-store.ts
+++ b/ui/web/src/stores/use-ui-store.ts
@@ -1,14 +1,17 @@
 import { create } from "zustand";
-import { LOCAL_STORAGE_KEYS } from "@/lib/constants";
+import i18n from "@/i18n";
+import { LOCAL_STORAGE_KEYS, type Language } from "@/lib/constants";
 
 export type Theme = "light" | "dark" | "system";
 
 interface UiState {
   theme: Theme;
+  language: Language;
   sidebarCollapsed: boolean;
   mobileSidebarOpen: boolean;
 
   setTheme: (theme: Theme) => void;
+  setLanguage: (language: Language) => void;
   toggleSidebar: () => void;
   setSidebarCollapsed: (collapsed: boolean) => void;
   setMobileSidebarOpen: (open: boolean) => void;
@@ -16,6 +19,7 @@ interface UiState {
 
 export const useUiStore = create<UiState>((set) => ({
   theme: (localStorage.getItem(LOCAL_STORAGE_KEYS.THEME) as Theme) ?? "dark",
+  language: (i18n.language as Language) ?? "en",
   sidebarCollapsed:
     localStorage.getItem(LOCAL_STORAGE_KEYS.SIDEBAR_COLLAPSED) === "true",
   mobileSidebarOpen: false,
@@ -25,6 +29,11 @@ export const useUiStore = create<UiState>((set) => ({
     set({ theme });
   },
 
+  setLanguage: (language) => {
+    i18n.changeLanguage(language);
+    set({ language });
+  },
+
   toggleSidebar: () =>
     set((state) => {
       const next = !state.sidebarCollapsed;