Worked on core stability and security improvements in the python/cpython and gchq/CyberChef repositories, focusing on robust error handling and documentation. Addressed crash prevention in Python’s os._path_normpath by validating memory allocation, and refined asyncio’s sendfile API to provide clearer error reporting. Enhanced the Windows profiler to prevent hangs by checking process status, and improved CyberChef’s reliability by resetting state after operation failures. Delivered a security-focused documentation update for the tarfile module, clarifying Windows-specific filename handling to reduce extraction risks. Utilized C, Python, and JavaScript, emphasizing memory management, systems programming, and cross-platform security in both code and documentation.