Worked on delivering Precompiled Header (PCH) support for Buck2 C++ builds, focusing on both the facebook/buck2-prelude and facebook/buck2 repositories. Implemented new rules and integrated PCH generation and consumption into the existing C++ compilation logic, aiming to reduce redundant header recompilations and improve local build performance. Leveraged expertise in build systems, C++, and compiler internals to ensure maintainability and extensibility of the solution. Used Bzl, C++, and Python to modify and extend rule-based build processes, establishing a foundation for broader performance optimizations across the codebase. The work emphasized maintainable engineering and measurable performance gains for C++ developers.