fix(chat): preserve retry attachments and per-answer context snapshots

backend/app/contracts.py

@@ -312,6 +312,7 @@ class ConversationListResponse(Contract):
 
 
 class ChatMessage(Contract):
+    context_captured: bool = False
     attachments: list[str] = Field(default_factory=list)
     workspace_context: WorkspaceContext | None = None
     activity: list[dict[str, Any]] = Field(default_factory=list)

backend/app/database/migrations.py

@@ -171,6 +171,7 @@ MIGRATIONS: list[str] = [
     """ALTER TABLE chat_conversations ADD COLUMN active_response_id TEXT;""",
     """ALTER TABLE chat_messages ADD COLUMN workspace_context_json TEXT;""",
     """ALTER TABLE chat_messages ADD COLUMN attachments_json TEXT NOT NULL DEFAULT '[]';""",
+    """ALTER TABLE chat_messages ADD COLUMN context_captured INTEGER NOT NULL DEFAULT 0;""",
 ]
 
 

backend/app/routes.py

@@ -506,6 +506,9 @@ async def chat(request: ChatRequest) -> StreamingResponse:
                     usage=usage,
                     activity=activity,
                     parent_message_id=user_message_id,
+                    workspace_context=request.workspace_context.model_dump() if request.workspace_context else None,
+                    attachments=request.attachments,
+                    context_captured=True,
                 )
 
     return StreamingResponse(stream(), media_type="text/event-stream")

backend/app/services/chat_history.py

@@ -39,6 +39,7 @@ def _message(row) -> ChatMessage:
         thinking=row["thinking"],
         activity=json.loads(row['activity_json']),
         attachments=json.loads(row['attachments_json']),
+        context_captured=bool(row['context_captured']),
         workspace_context=json.loads(row['workspace_context_json']) if row['workspace_context_json'] else None,
         citations=citations,
         tool_calls=json.loads(row["tool_calls_json"]),
@@ -130,6 +131,7 @@ def append_message(
     parent_message_id: str | None = None,
     workspace_context: dict | None = None,
     attachments: list[str] | None = None,
+    context_captured: bool = False,
 ) -> None:
     now = _now().isoformat()
     clean_title = (title or "").strip() or content[:30].strip() or "New conversation"
@@ -139,7 +141,7 @@ def append_message(
             _append_message_in_transaction(
                 conn, conversation_id, message_id=message_id, role=role, content=content,
                 title=clean_title, thinking=thinking, citations=citations, tool_calls=tool_calls,
-                usage=usage, now=now, activity=activity, parent_message_id=parent_message_id, workspace_context=workspace_context, attachments=attachments,
+                usage=usage, now=now, activity=activity, parent_message_id=parent_message_id, workspace_context=workspace_context, attachments=attachments, context_captured=context_captured,
             )
             conn.execute("COMMIT")
         except BaseException:
@@ -165,6 +167,7 @@ def _append_message_in_transaction(
     parent_message_id: str | None = None,
     workspace_context: dict | None = None,
     attachments: list[str] | None = None,
+    context_captured: bool = False,
 ) -> None:
     conversation = conn.execute(
         "SELECT 1 FROM chat_conversations WHERE conversation_id=?", (conversation_id,)
@@ -215,6 +218,7 @@ def _append_message_in_transaction(
     conn.execute('UPDATE chat_messages SET parent_message_id=?, activity_json=? WHERE message_id=?', (parent, json.dumps(activity or [], ensure_ascii=False), message_id))
     conn.execute('UPDATE chat_messages SET workspace_context_json=? WHERE message_id=?', (json.dumps(workspace_context, ensure_ascii=False) if workspace_context is not None else None, message_id))
     conn.execute('UPDATE chat_messages SET attachments_json=? WHERE message_id=?', (json.dumps(attachments or []),message_id))
+    conn.execute('UPDATE chat_messages SET context_captured=? WHERE message_id=?', (int(context_captured), message_id))
     # A late stream may be persisted, but must not steal the selected branch.
     response_id = conn.execute('SELECT active_response_id FROM chat_conversations WHERE conversation_id=?', (conversation_id,)).fetchone()[0]
     if active_leaf == parent and (role != 'assistant' or response_id is None or response_id == message_id):

backend/tests/test_chat_versions.py

@@ -50,3 +50,40 @@ def test_workspace_snapshots_and_agent_links_survive_history_reload():
     assert total == 2
     assert messages[0].workspace_context.model_dump() == snapshot
     assert messages[1].tool_calls == calls
+
+
+def test_regeneration_persists_context_per_answer_without_rewriting_original(monkeypatch):
+    import asyncio
+    from types import SimpleNamespace
+    from app.contracts import ChatRequest, Message, ModelEvent, ModelEventType
+    from app.routes import chat, utc_now
+    received=[]
+    class Adapter:
+        async def stream(self, request):
+            received.append(request)
+            yield ModelEvent(event=ModelEventType.text_delta, sequence=0, data={'text':'answer'}, timestamp=utc_now())
+            yield ModelEvent(event=ModelEventType.done, sequence=1, data={}, timestamp=utc_now())
+    monkeypatch.setattr('app.routes.provider_or_404',lambda _:SimpleNamespace(adapter=Adapter()))
+    # Keep attachment parsing out of this persistence test; the route must save raw IDs.
+    async def prepare(request, provider):
+        return request.model_copy(update={'attachments':[]})
+    monkeypatch.setattr('app.services.chat_attachments.prepare',prepare)
+    async def scenario():
+        history.create('Snapshots','snapshots')
+        for index,context in enumerate([{'file_path':'a.md','content':'A'},{'file_path':'b.md','content':'B'},None]):
+            req=ChatRequest(provider_id='test',model='test',use_rag=False,conversation_id='snapshots',
+                user_message_id='su',assistant_message_id=f'sa{index}',retry_message_id=f'sa{index-1}' if index else None,
+                messages=[Message(role='user',content='explain')],workspace_context=context,attachments=[f'file{index}.md'])
+            response=await chat(req)
+            _=[chunk async for chunk in response.body_iterator]
+        for index,path in enumerate(['a.md','b.md',None]):
+            history.select_version('snapshots',f'sa{index}')
+            messages,_=history.list_messages('snapshots',100,0)
+            assert messages[0].workspace_context.file_path=='a.md'
+            answer=messages[-1]
+            assert answer.context_captured
+            assert (answer.workspace_context.file_path if answer.workspace_context else None)==path
+            assert answer.attachments==[f'file{index}.md']
+        assert 'b.md' in received[1].system
+        assert received[2].system is None
+    asyncio.run(scenario())