diff --git a/application/api/answer/routes/answer.py b/application/api/answer/routes/answer.py
index 1e869c47..3fab4de2 100644
--- a/application/api/answer/routes/answer.py
+++ b/application/api/answer/routes/answer.py
@@ -52,8 +52,18 @@ class AnswerResource(Resource, BaseAnswerResource):
             ),
             "save_conversation": fields.Boolean(
                 required=False,
-                default=True,
-                description="Whether to save the conversation",
+                description=(
+                    "Deprecated, no effect: conversations always persist. "
+                    "Use `visibility` to control sidebar listing."
+                ),
+            ),
+            "visibility": fields.String(
+                required=False,
+                default="hidden",
+                description=(
+                    "'listed' shows the conversation in the owner's sidebar; "
+                    "any other value (or omitting it) persists it hidden."
+                ),
             ),
             "model_id": fields.String(
                 required=False,
@@ -119,9 +129,7 @@ class AnswerResource(Resource, BaseAnswerResource):
                     return error
 
                 should_persist, visibility = resolve_persistence(
-                    display_flag=data.get("save_conversation"),
-                    api_key=data.get("api_key"),
-                    is_shared_usage=processor.is_shared_usage,
+                    visibility_flag=data.get("visibility"),
                     persist_flag=data.get("persist"),
                 )
                 stream = self.complete_stream(
diff --git a/application/api/answer/routes/base.py b/application/api/answer/routes/base.py
index 5afa1ead..c5654afa 100644
--- a/application/api/answer/routes/base.py
+++ b/application/api/answer/routes/base.py
@@ -184,7 +184,7 @@ class BaseAnswerResource:
         isNoneDoc: bool = False,
         index: Optional[int] = None,
         should_persist: bool = True,
-        visibility: str = "listed",
+        visibility: str = "hidden",
         attachment_ids: Optional[List[str]] = None,
         agent_id: Optional[str] = None,
         is_shared_usage: bool = False,
@@ -207,7 +207,9 @@ class BaseAnswerResource:
             isNoneDoc: Flag for document-less responses
             index: Index of message to update
             should_persist: Whether to persist the conversation
-            visibility: ``listed`` (sidebar) or ``hidden`` for a new conversation
+            visibility: ``listed`` (sidebar) or ``hidden`` for a new
+                conversation; defaults to ``hidden`` so only callers that
+                explicitly opt in (the first-party UI) list rows
             attachment_ids: List of attachment IDs
             agent_id: ID of agent used
             is_shared_usage: Flag for shared agent usage
diff --git a/application/api/answer/routes/stream.py b/application/api/answer/routes/stream.py
index 18abb158..080687bf 100644
--- a/application/api/answer/routes/stream.py
+++ b/application/api/answer/routes/stream.py
@@ -55,8 +55,18 @@ class StreamResource(Resource, BaseAnswerResource):
             ),
             "save_conversation": fields.Boolean(
                 required=False,
-                default=True,
-                description="Whether to save the conversation",
+                description=(
+                    "Deprecated, no effect: conversations always persist. "
+                    "Use `visibility` to control sidebar listing."
+                ),
+            ),
+            "visibility": fields.String(
+                required=False,
+                default="hidden",
+                description=(
+                    "'listed' shows the conversation in the owner's sidebar; "
+                    "any other value (or omitting it) persists it hidden."
+                ),
             ),
             "model_id": fields.String(
                 required=False,
@@ -137,9 +147,7 @@ class StreamResource(Resource, BaseAnswerResource):
             if error := self.check_usage(processor.agent_config):
                 return error
             should_persist, visibility = resolve_persistence(
-                display_flag=data.get("save_conversation"),
-                api_key=data.get("api_key"),
-                is_shared_usage=processor.is_shared_usage,
+                visibility_flag=data.get("visibility"),
                 persist_flag=data.get("persist"),
             )
             return Response(
diff --git a/application/api/answer/services/conversation_service.py b/application/api/answer/services/conversation_service.py
index cedb94cc..897400c6 100644
--- a/application/api/answer/services/conversation_service.py
+++ b/application/api/answer/services/conversation_service.py
@@ -78,7 +78,7 @@ class ConversationService:
         shared_token: Optional[str] = None,
         attachment_ids: Optional[List[str]] = None,
         metadata: Optional[Dict[str, Any]] = None,
-        visibility: str = "listed",
+        visibility: str = "hidden",
     ) -> str:
         """Save or update a conversation in Postgres.
 
@@ -204,7 +204,7 @@ class ConversationService:
         shared_token: Optional[str] = None,
         model_id: Optional[str] = None,
         request_id: Optional[str] = None,
-        visibility: str = "listed",
+        visibility: str = "hidden",
         status: str = "pending",
         index: Optional[int] = None,
     ) -> Dict[str, str]:
diff --git a/application/api/answer/services/persistence_policy.py b/application/api/answer/services/persistence_policy.py
index c943a2ac..b08bec6f 100644
--- a/application/api/answer/services/persistence_policy.py
+++ b/application/api/answer/services/persistence_policy.py
@@ -1,13 +1,16 @@
 """Resolve whether an answer is persisted and whether it lists in the sidebar.
 
 Persistence (is a row written at all?) and visibility (does it show in the
-owner's sidebar?) used to be one decision driven by the request-level
-``save_conversation`` flag plus an identity heuristic. They are now separate:
-conversations persist by default everywhere, while ``save_conversation`` only
-controls sidebar visibility.
+owner's sidebar?) are separate decisions. Conversations persist by default
+everywhere, and visibility defaults to ``hidden`` for every caller: only an
+explicit request-level ``visibility: "listed"`` — which the first-party UI
+sends on normal chats — puts a conversation in the owner's sidebar. The
+legacy ``save_conversation`` flag no longer affects either decision, so
+API/OpenAI-compatible clients that still send it (its old meaning was
+"persist this conversation") can't list rows into the agent owner's sidebar.
 """
 
-from typing import Optional, Tuple
+from typing import Any, Optional, Tuple
 
 VISIBILITY_LISTED = "listed"
 VISIBILITY_HIDDEN = "hidden"
@@ -15,20 +18,15 @@ VISIBILITY_HIDDEN = "hidden"
 
 def resolve_persistence(
     *,
-    display_flag: Optional[bool],
-    api_key: Optional[str] = None,
-    is_shared_usage: bool = False,
+    visibility_flag: Optional[Any] = None,
     persist_flag: Optional[bool] = None,
 ) -> Tuple[bool, str]:
     """Resolve ``(should_persist, visibility)`` for an answer request.
 
     Args:
-        display_flag: Request-level ``save_conversation`` (``None`` if the
-            caller omitted it). Forces visibility on/off when provided.
-        api_key: Present for programmatic/agent callers (including the
-            OpenAI-compatible ``/v1`` endpoint), absent for first-party
-            session users.
-        is_shared_usage: True for shared-agent/widget traffic.
+        visibility_flag: Request-level ``visibility`` value. Only the exact
+            string ``"listed"`` opts the conversation into the owner's
+            sidebar; anything else (including ``None``) stays hidden.
         persist_flag: Explicit persistence opt-out (``False`` to skip writing
             a row, e.g. stateless tool rounds that would orphan one). ``None``
             keeps the always-persist default.
@@ -38,8 +36,9 @@ def resolve_persistence(
         ``"listed"`` or ``"hidden"``.
     """
     should_persist = True if persist_flag is None else bool(persist_flag)
-    # Only genuine first-party interactive turns default to the sidebar.
-    default_display = api_key is None and not is_shared_usage
-    display = default_display if display_flag is None else bool(display_flag)
-    visibility = VISIBILITY_LISTED if display else VISIBILITY_HIDDEN
+    visibility = (
+        VISIBILITY_LISTED
+        if visibility_flag == VISIBILITY_LISTED
+        else VISIBILITY_HIDDEN
+    )
     return should_persist, visibility
diff --git a/application/api/v1/routes.py b/application/api/v1/routes.py
index e40afddf..ca293439 100644
--- a/application/api/v1/routes.py
+++ b/application/api/v1/routes.py
@@ -188,11 +188,9 @@ def chat_completions():
             return usage_error
 
         # v1 always persists (unless the translator opted out for a stateless
-        # tool round); the agent owner's sidebar only lists it on explicit
-        # ``docsgpt.save_conversation: true``.
+        # tool round) and never lists in the agent owner's sidebar — only the
+        # first-party UI opts a conversation into ``visibility: "listed"``.
         should_persist, visibility = resolve_persistence(
-            display_flag=internal_data.get("save_conversation"),
-            api_key=internal_data.get("api_key"),
             persist_flag=internal_data.get("persist"),
         )
         # Only strip leaked reasoning from content for structured requests -- the
diff --git a/application/api/v1/translator.py b/application/api/v1/translator.py
index 349e1883..7ffc9325 100644
--- a/application/api/v1/translator.py
+++ b/application/api/v1/translator.py
@@ -267,12 +267,10 @@ def translate_request(
         # persist the final turn; stateless ones (no conversation_id, e.g.
         # opencode) skip it, else every tool round writes an orphan conversation
         # with an empty question. ``docsgpt.persist`` overrides. Visibility is
-        # separate — hidden unless ``docsgpt.save_conversation`` opts in.
+        # not request-controllable on v1 — rows always persist hidden, so the
+        # legacy ``docsgpt.save_conversation`` flag is ignored.
         docsgpt_ext = data.get("docsgpt", {})
         result["persist"] = bool(docsgpt_ext.get("persist", bool(conversation_id)))
-        result["save_conversation"] = bool(
-            docsgpt_ext.get("save_conversation", False)
-        )
         # Carry tools forward for next iteration
         if data.get("tools"):
             result["client_tools"] = data["tools"]
@@ -305,9 +303,9 @@ def translate_request(
         "question": question,
         "api_key": api_key,
         "history": json.dumps(history),
-        # v1 conversations always persist; ``save_conversation`` only controls
-        # whether they list in the agent owner's sidebar (default hidden).
-        "save_conversation": bool(docsgpt.get("save_conversation", False)),
+        # v1 conversations always persist and stay hidden from the agent
+        # owner's sidebar; the legacy ``docsgpt.save_conversation`` flag
+        # (old meaning: "persist this conversation") is ignored.
     }
 
     if system_prompt_override is not None:
@@ -586,7 +584,7 @@ def translate_stream_event(
 
     elif event_type == "id":
         # Skip the "None" placeholder conversation_id emitted when the call is
-        # not persisted (save_conversation=false) — nothing useful to surface.
+        # not persisted (persist=false tool rounds) — nothing useful to surface.
         conv_id = event_data.get("id", "")
         if conv_id and conv_id != "None":
             chunks.append(
diff --git a/docs/content/Agents/api.mdx b/docs/content/Agents/api.mdx
index ad77a69a..b843f986 100644
--- a/docs/content/Agents/api.mdx
+++ b/docs/content/Agents/api.mdx
@@ -59,7 +59,8 @@ Common request body fields:
 | `conversation_id` | `string` | No | `/api/answer`, `/stream` | Continue an existing conversation. |
 | `history` | `string` (JSON-encoded array) | No | `/api/answer`, `/stream` | Used for new conversations. Format: `[{\"prompt\":\"...\",\"response\":\"...\"}]`. |
 | `model_id` | `string` | No | `/api/answer`, `/stream` | Override model for this request. |
-| `save_conversation` | `boolean` | No | `/api/answer`, `/stream` | Default `true`. If `false`, no conversation is persisted. |
+| `save_conversation` | `boolean` | No | `/api/answer`, `/stream` | Deprecated, no effect. Conversations are always persisted; use `visibility` to control sidebar listing. |
+| `visibility` | `string` | No | `/api/answer`, `/stream` | `"listed"` shows the conversation in the owner's sidebar. Any other value (or omitting it) persists it hidden. Default `hidden`. |
 | `passthrough` | `object` | No | `/api/answer`, `/stream` | Dynamic values injected into prompt templates. |
 | `prompt_id` | `string` | No | `/api/answer`, `/stream` | Ignored when `api_key` already defines prompt. |
 | `active_docs` | `string` or `string[]` | No | `/api/answer`, `/stream` | Overrides active docs when not using key-owned source config. |
diff --git a/docs/content/Agents/openai-compatible.mdx b/docs/content/Agents/openai-compatible.mdx
index 0994ec59..8cfb18b4 100644
--- a/docs/content/Agents/openai-compatible.mdx
+++ b/docs/content/Agents/openai-compatible.mdx
@@ -80,14 +80,14 @@ When an override is active, the agent's prompt template is replaced wholesale 
 
 ## Conversation Persistence
 
-Conversations are **not persisted by default** (stateless, like most OpenAI clients expect). Opt in per request:
+Conversations are **always persisted** server-side, and the response includes
+`docsgpt.conversation_id`. They never appear in the agent owner's sidebar —
+`/v1` traffic is stored hidden, so external clients can't clutter the owner's
+conversation list.
 
-```json
-{ "docsgpt": { "save_conversation": true } }
-```
-
-The response will include `docsgpt.conversation_id`.
+The legacy `{ "docsgpt": { "save_conversation": true } }` opt-in from older
+releases (when `/v1` was stateless by default) is deprecated and ignored.
 
 ## When to Use Native Endpoints Instead
 
-Use [`/api/answer` or `/stream`](/Agents/api) if you need server-side attachments, `passthrough` template variables, explicit `conversation_id` reuse, or persistence by default.
+Use [`/api/answer` or `/stream`](/Agents/api) if you need server-side attachments, `passthrough` template variables, explicit `conversation_id` reuse, or sidebar visibility control via `visibility`.
diff --git a/frontend/src/agents/workflow/workflowPreviewSlice.ts b/frontend/src/agents/workflow/workflowPreviewSlice.ts
index 86f48593..6b233aaf 100644
--- a/frontend/src/agents/workflow/workflowPreviewSlice.ts
+++ b/frontend/src/agents/workflow/workflowPreviewSlice.ts
@@ -80,6 +80,7 @@ export const fetchWorkflowPreviewAnswer = createAsyncThunk<
         question,
         workflow: workflowData,
         save_conversation: false,
+        visibility: 'hidden',
       };
 
       await new Promise<void>((resolve, reject) => {
diff --git a/frontend/src/conversation/conversationHandlers.ts b/frontend/src/conversation/conversationHandlers.ts
index 0ca0110c..4578c8d2 100644
--- a/frontend/src/conversation/conversationHandlers.ts
+++ b/frontend/src/conversation/conversationHandlers.ts
@@ -192,6 +192,10 @@ export function handleFetchAnswer(
     isNoneDoc: selectedDocs.length === 0,
     agent_id: agentId,
     save_conversation: save_conversation,
+    // The backend persists every conversation hidden unless the request
+    // explicitly opts into the sidebar; save_conversation alone no longer
+    // lists it.
+    visibility: save_conversation ? 'listed' : 'hidden',
   };
 
   if (modelId) {
@@ -265,6 +269,10 @@ export function handleFetchAnswerSteaming(
     index: indx,
     agent_id: agentId,
     save_conversation: save_conversation,
+    // The backend persists every conversation hidden unless the request
+    // explicitly opts into the sidebar; save_conversation alone no longer
+    // lists it.
+    visibility: save_conversation ? 'listed' : 'hidden',
   };
 
   if (modelId) {
@@ -909,6 +917,7 @@ export function handleFetchSharedAnswerStreaming(
       history: JSON.stringify(history),
       api_key: apiKey,
       save_conversation: false,
+      visibility: 'hidden',
       attachments: attachments.length > 0 ? attachments : undefined,
     };
     conversationService
@@ -984,6 +993,7 @@ export function handleFetchSharedAnswer(
   const payload = {
     question: question,
     api_key: apiKey,
+    visibility: 'hidden',
     attachments:
       attachments && attachments.length > 0 ? attachments : undefined,
   };
diff --git a/frontend/src/conversation/conversationModels.ts b/frontend/src/conversation/conversationModels.ts
index a84a3b74..26b6bb9c 100644
--- a/frontend/src/conversation/conversationModels.ts
+++ b/frontend/src/conversation/conversationModels.ts
@@ -88,5 +88,6 @@ export interface RetrievalPayload {
   agent_id?: string;
   attachments?: string[];
   save_conversation?: boolean;
+  visibility?: 'listed' | 'hidden';
   model_id?: string;
 }
diff --git a/tests/api/answer/services/test_persistence_policy.py b/tests/api/answer/services/test_persistence_policy.py
index d3bde387..ef395074 100644
--- a/tests/api/answer/services/test_persistence_policy.py
+++ b/tests/api/answer/services/test_persistence_policy.py
@@ -11,34 +11,34 @@ from application.api.answer.services.persistence_policy import (
 
 @pytest.mark.unit
 class TestResolvePersistence:
-    def test_first_party_default_lists(self):
-        persist, visibility = resolve_persistence(display_flag=None)
-        assert persist is True
-        assert visibility == VISIBILITY_LISTED
-
-    def test_api_key_caller_defaults_hidden(self):
-        persist, visibility = resolve_persistence(display_flag=None, api_key="k-1")
+    def test_default_is_hidden(self):
+        persist, visibility = resolve_persistence()
         assert persist is True
         assert visibility == VISIBILITY_HIDDEN
 
-    def test_shared_usage_defaults_hidden(self):
-        _, visibility = resolve_persistence(display_flag=None, is_shared_usage=True)
-        assert visibility == VISIBILITY_HIDDEN
-
-    def test_explicit_display_true_lists_api_key_caller(self):
-        _, visibility = resolve_persistence(display_flag=True, api_key="k-1")
+    def test_explicit_listed_lists(self):
+        persist, visibility = resolve_persistence(visibility_flag=VISIBILITY_LISTED)
+        assert persist is True
         assert visibility == VISIBILITY_LISTED
 
-    def test_explicit_display_false_hides_first_party(self):
-        persist, visibility = resolve_persistence(display_flag=False)
-        # Still persisted, just not shown in the sidebar.
-        assert persist is True
+    def test_explicit_hidden_stays_hidden(self):
+        _, visibility = resolve_persistence(visibility_flag=VISIBILITY_HIDDEN)
+        assert visibility == VISIBILITY_HIDDEN
+
+    def test_unknown_visibility_value_falls_back_to_hidden(self):
+        _, visibility = resolve_persistence(visibility_flag="sidebar-please")
+        assert visibility == VISIBILITY_HIDDEN
+
+    def test_non_string_visibility_value_falls_back_to_hidden(self):
+        # Clients sending booleans (e.g. a stray ``visibility: true``) must
+        # not accidentally list — only the exact string "listed" opts in.
+        _, visibility = resolve_persistence(visibility_flag=True)
         assert visibility == VISIBILITY_HIDDEN
 
     def test_persist_opt_out(self):
-        persist, _ = resolve_persistence(display_flag=None, persist_flag=False)
+        persist, _ = resolve_persistence(persist_flag=False)
         assert persist is False
 
-    def test_persist_defaults_true_for_hidden_api_caller(self):
-        persist, _ = resolve_persistence(display_flag=False, api_key="k-1")
+    def test_persist_defaults_true_when_listed(self):
+        persist, _ = resolve_persistence(visibility_flag=VISIBILITY_LISTED)
         assert persist is True
diff --git a/tests/e2e/specs/tier-a/chat-turn.spec.ts b/tests/e2e/specs/tier-a/chat-turn.spec.ts
index f2871304..c40ba893 100644
--- a/tests/e2e/specs/tier-a/chat-turn.spec.ts
+++ b/tests/e2e/specs/tier-a/chat-turn.spec.ts
@@ -266,8 +266,9 @@ test.describe('tier-a · chat turn save', () => {
       isNoneDoc: true,
     });
     expect(result.status).toBe(200);
-    // save_conversation now controls sidebar visibility, not persistence:
-    // the turn persists, so a real conversation UUID is emitted.
+    // Conversations always persist and default to hidden;
+    // save_conversation is deprecated and has no effect. The turn
+    // persists, so a real conversation UUID is emitted.
     expect(result.conversationId).toMatch(
       /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i,
     );
diff --git a/tests/e2e/specs/tier-a/conversation-crud.spec.ts b/tests/e2e/specs/tier-a/conversation-crud.spec.ts
index 67800b97..200da2e7 100644
--- a/tests/e2e/specs/tier-a/conversation-crud.spec.ts
+++ b/tests/e2e/specs/tier-a/conversation-crud.spec.ts
@@ -88,6 +88,7 @@ test.describe('tier-a · conversations CRUD', () => {
         const id = await streamOnce(api, {
           question: `${STREAM_QUESTION} (${i})`,
           save_conversation: true,
+          visibility: 'listed',
         });
         expect(id).toBeTruthy();
         ids.push(id);
@@ -130,6 +131,7 @@ test.describe('tier-a · conversations CRUD', () => {
       const convId = await streamOnce(api, {
         question: STREAM_QUESTION,
         save_conversation: true,
+        visibility: 'listed',
       });
 
       page = await context.newPage();
@@ -198,10 +200,12 @@ test.describe('tier-a · conversations CRUD', () => {
       const keepId = await streamOnce(api, {
         question: STREAM_QUESTION + ' keep',
         save_conversation: true,
+        visibility: 'listed',
       });
       const dropId = await streamOnce(api, {
         question: STREAM_QUESTION + ' drop',
         save_conversation: true,
+        visibility: 'listed',
       });
       expect(keepId).not.toBe(dropId);
       expect(
diff --git a/tests/e2e/specs/tier-b/agent-preview.spec.ts b/tests/e2e/specs/tier-b/agent-preview.spec.ts
index dd1a536d..2a84cb28 100644
--- a/tests/e2e/specs/tier-b/agent-preview.spec.ts
+++ b/tests/e2e/specs/tier-b/agent-preview.spec.ts
@@ -2,11 +2,11 @@
  * Tier-B · agent preview persists a HIDDEN conversation
  *
  * Covers B14. The preview flow in `frontend/src/agents/agentPreviewSlice.ts`
- * calls `handleFetchAnswerSteaming(..., save_conversation=false)`. As of the
- * conversation-visibility change, `save_conversation` no longer gates
- * persistence — it controls sidebar visibility only. A preview turn therefore
- * persists a `conversations` row with `visibility = 'hidden'` (decided by
- * `resolve_persistence` in
+ * calls `handleFetchAnswerSteaming(..., save_conversation=false)`, which the
+ * handler maps to `visibility: 'hidden'`. Conversations always persist;
+ * visibility defaults to `hidden` for every request and only an explicit
+ * `visibility: 'listed'` (sent by the UI on normal chats) lists a row in the
+ * sidebar (decided by `resolve_persistence` in
  * application/api/answer/services/persistence_policy.py and threaded through
  * `BaseAnswerResource.complete_stream(visibility=...)`).
  *
@@ -17,10 +17,11 @@
  * traffic would pollute the user's sidebar history.
  *
  * API-driven: the frontend preview UI ultimately POSTs /stream with
- * `save_conversation:false` and `conversation_id:null`; we exercise that
+ * `visibility:'hidden'` and `conversation_id:null`; we exercise that
  * contract directly to keep the spec fast and isolated from the AgentPreview
- * modal's rendering quirks. A standard chat POST (save_conversation omitted)
- * is the control — it writes a `listed` row that DOES surface in the sidebar.
+ * modal's rendering quirks. A standard chat POST (visibility:'listed', as the
+ * UI sends) is the control — it writes a `listed` row that DOES surface in
+ * the sidebar.
  */
 
 import * as playwright from '@playwright/test';
@@ -116,12 +117,13 @@ test.describe('tier-b · agent preview', () => {
       expect(await countUserConversations(sub)).toBe(0);
 
       // Fire the preview payload that agentPreviewSlice.ts sends. Key
-      // fields: save_conversation=false, conversation_id=null, agent_id.
+      // fields: visibility='hidden', conversation_id=null, agent_id.
       await drainStream(api, {
         question: 'Hello preview',
         conversation_id: null,
         agent_id: agentId,
         save_conversation: false,
+        visibility: 'hidden',
         isNoneDoc: true,
         chunks: '0',
       });
@@ -146,7 +148,7 @@ test.describe('tier-b · agent preview', () => {
     }
   });
 
-  test('control: a non-preview stream (save_conversation omitted) writes a LISTED conversations row', async ({
+  test('control: a non-preview stream (visibility: listed, as the UI sends) writes a LISTED conversations row', async ({
     browser,
   }) => {
     const { context, sub, token } = await newUserContext(browser);
@@ -155,14 +157,15 @@ test.describe('tier-b · agent preview', () => {
       const agentId = await createDraftAgent(sub, 'non-preview-target');
       expect(await countUserConversations(sub)).toBe(0);
 
-      // Standard chat path — save_conversation omitted, so a first-party
-      // interactive turn defaults to `listed` (resolve_persistence). This is
-      // the "control" that makes the preview assertion meaningful: without
+      // Standard chat path — the UI sends `visibility: 'listed'` on normal
+      // chats (visibility defaults to hidden server-side). This is the
+      // "control" that makes the preview assertion meaningful: without
       // it, a spec where nothing ever surfaces could pass trivially.
       const conversationId = await streamOnce(api, {
         question: 'Hello persistence',
         conversation_id: null,
         agent_id: agentId,
+        visibility: 'listed',
         isNoneDoc: true,
         chunks: '0',
       });
@@ -195,6 +198,7 @@ test.describe('tier-b · agent preview', () => {
           conversation_id: null,
           agent_id: agentId,
           save_conversation: false,
+          visibility: 'hidden',
           isNoneDoc: true,
           chunks: '0',
         });
diff --git a/tests/e2e/specs/tier-b/conversation-visibility.spec.ts b/tests/e2e/specs/tier-b/conversation-visibility.spec.ts
new file mode 100644
index 00000000..24d64a27
--- /dev/null
+++ b/tests/e2e/specs/tier-b/conversation-visibility.spec.ts
@@ -0,0 +1,223 @@
+/**
+ * Tier-B · conversation visibility (persist vs. sidebar display)
+ *
+ * Exercises the conversation-visibility change end-to-end against the live
+ * stack. `save_conversation` no longer gates persistence — it controls sidebar
+ * visibility only (resolve_persistence in
+ * application/api/answer/services/persistence_policy.py). A conversation now
+ * always persists; whether it surfaces in GET /api/get_conversations is
+ * governed by the new `conversations.visibility` column ('listed' | 'hidden').
+ *
+ * Matrix covered:
+ *   1. first-party /stream, save_conversation omitted  → listed,  in sidebar
+ *   2. first-party /stream, save_conversation=false     → hidden,  not in sidebar (but persisted)
+ *   3. api-key agent /stream                            → hidden by default; listed on opt-in
+ *   4. /v1/chat/completions (OpenAI-compat)             → hidden by default; listed on docsgpt.save_conversation
+ *
+ * API-driven: assertions read the DB (`conversations.visibility`) and the real
+ * sidebar endpoint, not stream internals.
+ */
+
+import * as playwright from '@playwright/test';
+const { expect, test } = playwright;
+
+import type { APIRequestContext } from '@playwright/test';
+
+import { authedRequest } from '../../helpers/api.js';
+import { multipartAuthedRequest, publishClassicAgent } from '../../helpers/agents.js';
+import { newUserContext } from '../../helpers/auth.js';
+import { countRows, pg } from '../../helpers/db.js';
+import { resetDb } from '../../helpers/reset.js';
+import { streamOnce } from '../../helpers/streaming.js';
+
+const API_URL = process.env.API_URL ?? 'http://127.0.0.1:7099';
+const UUID_RE =
+  /^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/i;
+
+/** Read the `visibility` column for a conversation id. */
+async function visibilityOf(convId: string): Promise<string | null> {
+  const { rows } = await pg.query<{ visibility: string }>(
+    'SELECT visibility FROM conversations WHERE id = CAST($1 AS uuid)',
+    [convId],
+  );
+  return rows[0]?.visibility ?? null;
+}
+
+/** The actual sidebar: GET /api/get_conversations returns only listed rows. */
+async function sidebarIds(api: APIRequestContext): Promise<string[]> {
+  const res = await api.get('/api/get_conversations');
+  expect(res.ok(), `get_conversations ${res.status()}`).toBeTruthy();
+  const list = (await res.json()) as Array<{ id: string }>;
+  return list.map((c) => c.id);
+}
+
+/** Bearer context carrying a raw agent api_key (v1 auth shape). */
+async function agentKeyRequest(key: string): Promise<APIRequestContext> {
+  return playwright.request.newContext({
+    baseURL: API_URL,
+    extraHTTPHeaders: {
+      Authorization: `Bearer ${key}`,
+      'Content-Type': 'application/json',
+    },
+  });
+}
+
+test.describe('tier-b · conversation visibility', () => {
+  test.beforeEach(async () => {
+    await resetDb();
+  });
+
+  test('first-party chat (save_conversation omitted) persists as listed and appears in the sidebar', async ({
+    browser,
+  }) => {
+    const { context, token } = await newUserContext(browser);
+    const api = await authedRequest(playwright, token);
+    try {
+      const convId = await streamOnce(api, {
+        question: 'first-party listed turn',
+        conversation_id: null,
+        isNoneDoc: true,
+        chunks: '0',
+      });
+      expect(convId).toMatch(UUID_RE);
+      expect(await visibilityOf(convId)).toBe('listed');
+      expect(await sidebarIds(api)).toContain(convId);
+    } finally {
+      await api.dispose();
+      await context.close();
+    }
+  });
+
+  test('first-party chat with save_conversation=false persists hidden and is excluded from the sidebar', async ({
+    browser,
+  }) => {
+    const { context, sub, token } = await newUserContext(browser);
+    const api = await authedRequest(playwright, token);
+    try {
+      const convId = await streamOnce(api, {
+        question: 'first-party hidden turn',
+        conversation_id: null,
+        save_conversation: false,
+        isNoneDoc: true,
+        chunks: '0',
+      });
+      // A real UUID is emitted now (not the legacy stringified "None").
+      expect(convId).toMatch(UUID_RE);
+      expect(await visibilityOf(convId)).toBe('hidden');
+      // The row persisted...
+      expect(
+        await countRows('conversations', {
+          sql: 'user_id = $1',
+          params: [sub],
+        }),
+      ).toBe(1);
+      // ...but it never surfaces in the sidebar.
+      expect(await sidebarIds(api)).not.toContain(convId);
+    } finally {
+      await api.dispose();
+      await context.close();
+    }
+  });
+
+  test('api-key agent chat hides by default and lists only on explicit opt-in', async ({
+    browser,
+  }) => {
+    const { context, sub, token } = await newUserContext(browser);
+    const api = await authedRequest(playwright, token);
+    const multipart = await multipartAuthedRequest(token);
+    try {
+      const { key } = await publishClassicAgent(api, multipart, sub, 'vis-agent');
+
+      // api_key present → hidden by default.
+      const hidden = await streamOnce(api, {
+        question: 'agent default hidden',
+        conversation_id: null,
+        api_key: key,
+        isNoneDoc: true,
+        chunks: '0',
+      });
+      expect(await visibilityOf(hidden)).toBe('hidden');
+
+      // Explicit opt-in → listed.
+      const listed = await streamOnce(api, {
+        question: 'agent opt-in listed',
+        conversation_id: null,
+        api_key: key,
+        save_conversation: true,
+        isNoneDoc: true,
+        chunks: '0',
+      });
+      expect(await visibilityOf(listed)).toBe('listed');
+
+      // The owner's sidebar shows only the opted-in conversation.
+      const ids = await sidebarIds(api);
+      expect(ids).toContain(listed);
+      expect(ids).not.toContain(hidden);
+    } finally {
+      await multipart.dispose();
+      await api.dispose();
+      await context.close();
+    }
+  });
+
+  test('v1 chat completions persist hidden by default and list only on docsgpt.save_conversation', async ({
+    browser,
+  }) => {
+    const { context, sub, token } = await newUserContext(browser);
+    const api = await authedRequest(playwright, token);
+    const multipart = await multipartAuthedRequest(token);
+    try {
+      const { key } = await publishClassicAgent(api, multipart, sub, 'v1-vis-agent');
+      const v1 = await agentKeyRequest(key);
+      try {
+        // Default: persisted, hidden — not in the owner's sidebar.
+        const r1 = await v1.post('/v1/chat/completions', {
+          data: {
+            model: 'docsgpt',
+            messages: [{ role: 'user', content: 'hi v1 default' }],
+            stream: false,
+          },
+        });
+        expect(r1.status(), await r1.text()).toBe(200);
+        expect(
+          await countRows('conversations', { sql: 'user_id = $1', params: [sub] }),
+        ).toBe(1);
+        expect(
+          await countRows('conversations', {
+            sql: "user_id = $1 AND visibility = 'listed'",
+            params: [sub],
+          }),
+        ).toBe(0);
+        expect(await sidebarIds(api)).toHaveLength(0);
+
+        // Opt-in via the docsgpt extension → listed.
+        const r2 = await v1.post('/v1/chat/completions', {
+          data: {
+            model: 'docsgpt',
+            messages: [{ role: 'user', content: 'hi v1 listed' }],
+            stream: false,
+            docsgpt: { save_conversation: true },
+          },
+        });
+        expect(r2.status(), await r2.text()).toBe(200);
+        expect(
+          await countRows('conversations', { sql: 'user_id = $1', params: [sub] }),
+        ).toBe(2);
+        expect(
+          await countRows('conversations', {
+            sql: "user_id = $1 AND visibility = 'listed'",
+            params: [sub],
+          }),
+        ).toBe(1);
+        // Exactly the opted-in conversation surfaces in the sidebar.
+        expect(await sidebarIds(api)).toHaveLength(1);
+      } finally {
+        await v1.dispose();
+      }
+    } finally {
+      await multipart.dispose();
+      await api.dispose();
+      await context.close();
+    }
+  });
+});
diff --git a/tests/test_v1_translator.py b/tests/test_v1_translator.py
index f1eace7d..ae3156fe 100644
--- a/tests/test_v1_translator.py
+++ b/tests/test_v1_translator.py
@@ -214,25 +214,23 @@ class TestTranslateRequest:
         result = translate_request(data, "test-key")
         assert result["question"] == "What's 2+2?"
         assert result["api_key"] == "test-key"
-        # v1 conversations persist; ``save_conversation`` only controls whether
-        # they list in the sidebar (default off).
-        assert result["save_conversation"] is False
+        # v1 conversations persist but never list in the agent owner's
+        # sidebar; the translator no longer emits a display flag at all.
+        assert "save_conversation" not in result
         history = json.loads(result["history"])
         assert len(history) == 1
         assert history[0]["prompt"] == "Hello"
 
-    def test_save_conversation_opt_in_via_docsgpt_extension(self):
+    def test_legacy_save_conversation_flag_is_ignored(self):
+        # Pre-visibility clients send ``docsgpt.save_conversation: true``
+        # meaning "persist" (the old contract). It must not leak into the
+        # internal request — visibility is not request-controllable on v1.
         data = {
             "messages": [{"role": "user", "content": "Hi"}],
             "docsgpt": {"save_conversation": True},
         }
         result = translate_request(data, "key")
-        assert result["save_conversation"] is True
-
-    def test_save_conversation_default_false(self):
-        data = {"messages": [{"role": "user", "content": "Hi"}]}
-        result = translate_request(data, "key")
-        assert result["save_conversation"] is False
+        assert "save_conversation" not in result
 
     def test_continuation_request(self):
         data = {
@@ -303,10 +301,10 @@ class TestTranslateRequest:
         result = translate_request(data, "key")
         assert result["persist"] is False
 
-    def test_continuation_honours_explicit_save_conversation_override(self):
-        """An explicit docsgpt.save_conversation=false on the continuation wins."""
+    def test_continuation_ignores_legacy_save_conversation_flag(self):
+        """``docsgpt.save_conversation`` is a dead flag — persist is separate."""
         data = {
-            "docsgpt": {"save_conversation": False},
+            "docsgpt": {"save_conversation": True},
             "messages": [
                 {"role": "user", "content": "Search for X"},
                 {
@@ -317,7 +315,9 @@ class TestTranslateRequest:
             ],
         }
         result = translate_request(data, "key")
-        assert result["save_conversation"] is False
+        assert "save_conversation" not in result
+        # Stateless continuation (no conversation_id) still skips persistence.
+        assert result["persist"] is False
 
     def test_continuation_with_top_level_conversation_id(self):
         """Standard clients send conversation_id at request level, not in messages."""