diff --git a/docsgpt/storage/db/repositories/agents.py b/docsgpt/storage/db/repositories/agents.py
index 78c2bb80..8676966b 100644
--- a/docsgpt/storage/db/repositories/agents.py
+++ b/docsgpt/storage/db/repositories/agents.py
@@ -43,7 +43,7 @@ class AgentsRepository:
             "limited_token_mode", "limited_request_mode",
             "allow_system_prompt_override",
             "shared", "shared_token", "shared_metadata",
-            "tools", "json_schema", "models", "config", "legacy_mongo_id",
+            "tools", "json_schema", "models", "config", "resource_sponsors", "legacy_mongo_id",
             "created_at", "updated_at", "last_used_at",
         }
 
diff --git a/frontend/src/agents/components/SponsoredResourcesNotice.test.tsx b/frontend/src/agents/components/SponsoredResourcesNotice.test.tsx
index fa3a510f..ef92086e 100644
--- a/frontend/src/agents/components/SponsoredResourcesNotice.test.tsx
+++ b/frontend/src/agents/components/SponsoredResourcesNotice.test.tsx
@@ -1,6 +1,9 @@
 import { act } from 'react';
 import { createRoot, type Root } from 'react-dom/client';
 
+import i18n from 'i18next';
+import { initReactI18next } from 'react-i18next';
+
 import type { Agent, ResourceSponsor } from '../types';
 import SponsoredResourcesNotice from './SponsoredResourcesNotice';
 
@@ -86,6 +89,36 @@ describe('SponsoredResourcesNotice', () => {
     expect(container.innerHTML).toBe('');
   });
 
+  it('joins names for the app language and does not escape them', async () => {
+    await i18n.use(initReactI18next).init({
+      lng: 'jp',
+      resources: {
+        jp: {
+          translation: {
+            agents: {
+              form: { sponsors: { addedBy: '{{person}}: {{names}}' } },
+            },
+          },
+        },
+      },
+    });
+    try {
+      await render({
+        ...baseAgent,
+        resource_sponsors: [
+          sponsor({ id: 'docs/a' }),
+          sponsor({ id: 'docs/b' }),
+        ],
+      });
+      const expected = new Intl.ListFormat('ja', {
+        type: 'conjunction',
+      }).format(['name-docs/a', 'name-docs/b']);
+      expect(container.textContent).toBe(`bob@example.com: ${expected}`);
+    } finally {
+      await i18n.changeLanguage('en');
+    }
+  });
+
   it('splits running and no-longer-running items', async () => {
     await render({
       ...baseAgent,
diff --git a/frontend/src/agents/components/SponsoredResourcesNotice.tsx b/frontend/src/agents/components/SponsoredResourcesNotice.tsx
index 79d8fd26..42c6c687 100644
--- a/frontend/src/agents/components/SponsoredResourcesNotice.tsx
+++ b/frontend/src/agents/components/SponsoredResourcesNotice.tsx
@@ -4,6 +4,7 @@ import { useTranslation } from 'react-i18next';
 import { Alert, AlertDescription } from '@/components/ui/alert';
 
 import { can, isOwner } from '../../utils/accessUtils';
+import { intlLocale } from '../../utils/dateTimeUtils';
 import type { Agent, ResourceSponsor } from '../types';
 
 type SponsoredResourcesNoticeProps = {
@@ -34,7 +35,7 @@ export default function SponsoredResourcesNotice({
   agent,
   resolveName,
 }: SponsoredResourcesNoticeProps) {
-  const { t } = useTranslation();
+  const { t, i18n } = useTranslation();
   const sponsors = agent.resource_sponsors ?? [];
   const showAttachNote = !isOwner(agent) && can(agent, 'edit');
   const active = groupByPerson(sponsors.filter((s) => s.active));
@@ -42,8 +43,11 @@ export default function SponsoredResourcesNotice({
 
   if (!showAttachNote && sponsors.length === 0) return null;
 
+  const listFormat = new Intl.ListFormat(intlLocale(i18n.language), {
+    type: 'conjunction',
+  });
   const names = (items: ResourceSponsor[]) =>
-    items.map((item) => resolveName(item)).join(', ');
+    listFormat.format(items.map((item) => resolveName(item)));
 
   return (
     <div className="flex flex-col gap-3 sm:col-span-2">
@@ -63,6 +67,7 @@ export default function SponsoredResourcesNotice({
             {active.map(([person, items]) => (
               <p key={person}>
                 {t('agents.form.sponsors.addedBy', {
+                  interpolation: { escapeValue: false },
                   person,
                   names: names(items),
                 })}
@@ -78,6 +83,7 @@ export default function SponsoredResourcesNotice({
             {inactive.map(([person, items]) => (
               <p key={person}>
                 {t('agents.form.sponsors.unavailable', {
+                  interpolation: { escapeValue: false },
                   person,
                   names: names(items),
                 })}
diff --git a/frontend/src/teams/accessSettings.ts b/frontend/src/teams/accessSettings.ts
index 02caa3c4..46306127 100644
--- a/frontend/src/teams/accessSettings.ts
+++ b/frontend/src/teams/accessSettings.ts
@@ -157,8 +157,15 @@ export function capabilityLines(
 }
 
 // A teams API error carries the server's message; anything else (a network
-// failure) falls back to the caller's generic copy.
-export const errorMessage = (error: unknown, fallback: string): string =>
-  error instanceof Error && error.name === 'TeamsApiError' && error.message
-    ? error.message
+// failure) falls back to the caller's generic copy. Matched by shape, not
+// `instanceof`: a thunk's unwrap() rethrows a serialized plain object.
+export const errorMessage = (error: unknown, fallback: string): string => {
+  const e = error as { name?: unknown; message?: unknown } | null;
+  return typeof e === 'object' &&
+    e !== null &&
+    e.name === 'TeamsApiError' &&
+    typeof e.message === 'string' &&
+    e.message
+    ? e.message
     : fallback;
+};
diff --git a/frontend/src/teams/teamsSlice.test.ts b/frontend/src/teams/teamsSlice.test.ts
index ac4f6ffa..03897815 100644
--- a/frontend/src/teams/teamsSlice.test.ts
+++ b/frontend/src/teams/teamsSlice.test.ts
@@ -10,6 +10,7 @@ vi.mock('../api/services/teamsService', () => ({
 
 import { configureStore } from '@reduxjs/toolkit';
 
+import { errorMessage } from './accessSettings';
 import reducer, { deleteTeam, loadTeams, Team } from './teamsSlice';
 
 const team: Team = { id: 't1', name: 'Ops', slug: 'ops', owner_id: 'u1' };
@@ -41,6 +42,33 @@ describe('teamsSlice', () => {
     expect(store.getState().teams.teams).toHaveLength(1);
   });
 
+  it("surfaces the server's reason through unwrap()", async () => {
+    // unwrap() rethrows a serialized plain object, not the Error instance.
+    remove.mockRejectedValue(
+      Object.assign(new Error('Only the owner can delete'), {
+        name: 'TeamsApiError',
+      }),
+    );
+    const store = makeStore();
+    const rejection = await store
+      .dispatch(deleteTeam({ id: 't1', token: null }))
+      .unwrap()
+      .catch((error: unknown) => error);
+    expect(errorMessage(rejection, 'fallback')).toBe(
+      'Only the owner can delete',
+    );
+  });
+
+  it('keeps the fallback for a non-teams rejection', async () => {
+    remove.mockRejectedValue(new Error('network down'));
+    const store = makeStore();
+    const rejection = await store
+      .dispatch(deleteTeam({ id: 't1', token: null }))
+      .unwrap()
+      .catch((error: unknown) => error);
+    expect(errorMessage(rejection, 'fallback')).toBe('fallback');
+  });
+
   it('keeps the team when a 2xx body says success:false', async () => {
     remove.mockResolvedValue({ success: false, message: 'nope' });
     const store = makeStore();
diff --git a/tests/storage/db/repositories/test_agents.py b/tests/storage/db/repositories/test_agents.py
index df9ea870..a6d9e8a2 100644
--- a/tests/storage/db/repositories/test_agents.py
+++ b/tests/storage/db/repositories/test_agents.py
@@ -49,6 +49,12 @@ class TestCreate:
         )
         assert doc["legacy_mongo_id"] == "507f1f77bcf86cd799439011"
 
+    def test_create_with_resource_sponsors(self, pg_conn):
+        repo = _repo(pg_conn)
+        sponsors = {"tool:t1": "editor-1"}
+        doc = repo.create("u", "a", "draft", resource_sponsors=sponsors)
+        assert doc["resource_sponsors"] == sponsors
+
     def test_create_normalizes_blank_key_to_null(self, pg_conn):
         repo = _repo(pg_conn)
         doc = repo.create("u", "a", "draft", key="")