Fix MCP endpoint thread_id to use valid MongoDB ObjectId

- Changed thread_id from ISO timestamp format to valid ObjectId
- MongoDB expects 24-character hex string for ObjectId
- Fixes error: 'mcp_2025-08-16T06:43:58...' is not a valid ObjectId
- Updated tests to verify ObjectId format

Author: waleedkadous

src/ansari/app/main_api.py

@@ -986,8 +986,10 @@ async def mcp_complete(request: Request):
 
     # Create a message logger with MCP source type for tracking
     # Note: Since this is unauthenticated, we use a system user ID for MCP traffic
+    from bson import ObjectId
     mcp_user_id = "mcp_system_user"
-    thread_id = f"mcp_{datetime.now(timezone.utc).isoformat()}"
+    # Generate a new ObjectId for the thread
+    thread_id = str(ObjectId())
 
     message_logger = MessageLogger(
         db,

tests/unit/test_mcp_endpoint.py

@@ -92,7 +92,10 @@ def test_mcp_endpoint_uses_mcp_source_type(self, mock_db, mock_message_logger, c
         call_args = mock_message_logger.call_args
         assert call_args[0][1] == SourceType.MCP  # Second argument is source_type
         assert call_args[0][2] == "mcp_system_user"  # Third argument is user_id
-        assert call_args[0][3].startswith("mcp_")  # Fourth argument is thread_id
+        # Fourth argument is thread_id - should be a valid ObjectId string (24 hex chars)
+        thread_id = call_args[0][3]
+        assert len(thread_id) == 24  # ObjectId strings are 24 characters
+        assert all(c in '0123456789abcdef' for c in thread_id)  # All hex characters
 
     def test_mcp_endpoint_handles_empty_messages(self, client):
         """Test that the MCP endpoint handles empty message lists gracefully."""
@@ -164,10 +167,6 @@ def test_mcp_endpoint_thread_id_format(self, client, mock_presenter):
             call_args = mock_message_logger.call_args
             thread_id = call_args[0][3]
 
-            # Verify thread_id starts with "mcp_" and contains ISO timestamp
-            assert thread_id.startswith("mcp_")
-            # The rest should be an ISO timestamp
-            timestamp_part = thread_id[4:]  # Remove "mcp_" prefix
-            # Basic check that it looks like an ISO timestamp
-            assert "T" in timestamp_part  # ISO format has T separator
-            assert ":" in timestamp_part  # Has time components
+            # Verify thread_id is a valid ObjectId string
+            assert len(thread_id) == 24  # ObjectId strings are 24 characters
+            assert all(c in '0123456789abcdef' for c in thread_id)  # All hex characters