Worked on enhancing Bazel compatibility within the Buck2 repository by implementing targeted Starlark language improvements. Focused on backend development using Rust, the work introduced optional start and end parameters to the str.startswith and str.endswith functions, and enabled named default arguments in dict.pop, aligning Buck2’s Starlark integration more closely with Bazel’s specification and Python semantics. Developed and maintained comprehensive test coverage for these changes, ensuring all existing and new tests passed and updating conformance checks as needed. This effort reduced migration friction and improved build script portability, demonstrating a methodical approach to language interoperability and robust backend engineering practices.