Worked on the bytedance/deer-flow repository to enhance reliability by addressing background task management in Python. Developed a mechanism that defers cleanup of background tasks until they reach a terminal state, preventing stale entries after polling timeouts and reducing race conditions between the poll loop and task lifecycle. The solution aligned with cooperative cancellation semantics in asynchronous programming, mapping cancellation flow to the asyncio CancelledError path and scheduling deferred cleanup tasks. Focused on robust task management and unit testing, the work improved the system’s handling of background processes, ensuring safer and more predictable cleanup without introducing new features during the period.