During April 2026, Willem Jiang enhanced the bytedance/deer-flow repository by improving Feishu command parsing reliability and test coverage. He centralized command recognition logic by introducing a shared frozenset of known Feishu commands, ensuring both the parser and ChannelManager referenced a single authoritative source. This approach reduced misrouting of slash-prefixed text and improved routing accuracy between command and chat pipelines. Willem expanded the Python-based test suite with parameterized cases to validate command recognition and edge scenarios, aligning behavior across components. His work demonstrated depth in backend development, API integration, and unit testing, resulting in more robust and maintainable command handling.