mcp-sse-error-handling-client-call-tool-hangs-when-receiving-invalid-json-8efa1a4a

THEN Ensure that errors during SSE event processing are correctly propagated to the client. Validate JSON before parsing and handle exceptions by sending an error response message that the client can interpret, rather than sending the exception object. Implement a retry mechanism or timeout to prevent client from hanging indefinitely.

try:
    message = JSONRPCMessage.model_validate_json(sse.data)
except Exception as exc:
    error_response = JSONRPCError(id=original_request_id, error={"code": -32700, "message": "Parse error"})
    await read_stream_writer.send(SessionMessage(JSONRPCMessage(error_response)))
    return True