Update app.py

app.py

@@ -133,14 +133,15 @@ async def handle_sse(request: Request):
             )
             logger.debug(f"Sent endpoint event: {endpoint_data}")
             async for session_message in write_stream_reader:
-                # Since session_message might be a dict or a SessionMessage, handle both cases
-                if isinstance(session_message, dict):
-                    event_data = session_message
-                    logger.debug(f"Received SSE event (dict): {event_data}")
-                else:
+                # Since SseServerTransport expects a SessionMessage, we'll handle messages manually
+                # and send raw SSE events to avoid the error in SseServerTransport's sse_writer
+                if hasattr(session_message, 'message'):
                     message_data = session_message.message.model_dump_json(by_alias=True, exclude_none=True)
                     event_data = json.loads(message_data)
-                    logger.debug(f"Received SSE event (SessionMessage): {event_data}")
+                    logger.debug(f"Received SessionMessage: {event_data}")
+                else:
+                    event_data = session_message
+                    logger.debug(f"Received dict event: {event_data}")
                 # Extract session_id from the endpoint event
                 if not session_id and event_data.get("event") == "endpoint":
                     endpoint_url = event_data.get("data", "")