Worked on the facebook/pyrefly repository to enhance type analysis and descriptor semantics in Python and Rust codebases. Developed a feature enabling TypeVar resolution across deeply nested module paths by updating AST binding logic and internal data structures, allowing for more accurate type inference in complex scenarios. Addressed a bug in descriptor detection for annotation-only fields by introducing initialization tracking and refining descriptor handling, which improved conformance with expected behaviors. The work included expanding test coverage and implementing new helper functions, resulting in more reliable backend tooling and maintainable code. Focus areas included backend development, testing, and advanced type system support.