During September 2025, Yifan Tao developed a new not_match query type for the coze-dev/coze-loop repository, enhancing observability filtering by enabling exclusion of data points containing specific substrings in trace data. He implemented the backend logic in Go, integrated SQL generation for efficient query execution, and expanded unit test coverage to ensure correctness across the new functionality. By focusing on backend development and data filtering, Yifan addressed the need for more granular trace filtering in observability workflows. This work laid the foundation for more expressive queries, reducing diagnostic noise and supporting faster, more targeted investigations without introducing major bug fixes that month.