Karthikeyan Arumugam focused on improving build stability and header compatibility in the ROCm/rccl repository during August 2025. He addressed a compilation issue caused by HIP’s removal of the cstring header by explicitly including it in utils.h, ensuring that string utilities continued to function reliably. Working primarily with C++ and leveraging his expertise in build systems and dependency management, Karthikeyan’s targeted fix reduced the risk of future build failures and improved code maintainability. His work contributed to smoother CI processes and faster debugging by proactively aligning header usage with upstream changes, demonstrating careful attention to evolving dependencies and code health.