Worked on enhancing the reliability of the Lambda-based SSH key registration flow in the skypilot-org/skypilot repository. Addressed concurrency issues by implementing a file locking mechanism in Python, ensuring that duplicate SSH keys are not registered when multiple threads attempt simultaneous registration. Focused on backend development and threading, the solution improved the idempotency and safety of the authentication setup within AWS Lambda environments. Emphasized unit testing to validate the fix and reduce operational risk in production deployments. No new features were introduced during this period, but the work strengthened concurrency handling and maintainability of the Lambda authentication process.