During June 2025, contributed to the facebook/pyrefly repository by addressing a NamedTuple validation bug that previously allowed fields without default values to follow those with defaults, which could lead to invalid class definitions. The solution involved refining error handling logic in Rust to enforce correct field ordering and enhance error reporting, making it easier for developers to identify and resolve misordered fields. All changes were validated through comprehensive testing, ensuring no regressions in related NamedTuple functionality. This targeted fix improved the reliability of Python typing utilities, reduced downstream defects, and maintained the stability of core data modeling features within the project.