During their two-month tenure, XL developed and enhanced a robust skills management framework for the openai/codex and openai/skills repositories, focusing on scalable skill discovery, enablement, and invocation. They rearchitected backend systems using Rust and Python, introducing a unified ConfigLayerStack for skill metadata and dynamic configuration, while supporting cross-platform file operations and symbolic link handling. XL improved the user experience by refining UI components for skill selection and administration, integrating feature flags, and clarifying documentation. Their work addressed multi-tenant rollout safety, maintainability, and test reliability, demonstrating depth in backend development, asynchronous programming, and system design across both API and UI layers.