Runze worked on the protocolbuffers/protobuf repository, focusing on improving descriptor validation to enhance build reliability and developer experience. He implemented a targeted solution in C++ that rejects protocol buffer symbol names beginning with numeric characters, addressing a common source of invalid configurations. By introducing precise error handling and actionable feedback, Runze enabled developers to quickly identify and correct naming convention violations. His approach included robust unit testing to ensure correctness and maintainability. This work reduced debugging time by catching errors early in the CI process, demonstrating depth in input validation, error reporting, and C++ development within a complex codebase.