Worked on the google/mcp-security repository with a focus on backend development and type hinting using Python. Addressed a critical bug by correcting the return type of the internal API function get_entities_related_to_a_collection, changing it from dict to list[dict] to accurately reflect the actual output. This adjustment improved type safety and predictability for downstream consumers, ensuring that the API contract is clear and reliable. The work emphasized code maintainability and API surface stability, with updates to both type annotations and associated tests. No new features were released during this period, as efforts centered on enhancing code quality and correctness.