Worked on the awslabs/mcp repository to enhance security and reliability in the AWS API MCP server by implementing local file system access control. Developed a feature that allows administrators to disable local file access via an environment variable, refining path validation logic and introducing streaming validation for blob paths. Consolidated and refactored file system controls in Python to improve maintainability, removing outdated modules and centralizing validation logic. Increased test coverage and updated documentation to reflect new configuration options. Focused on backend development, API design, and testing, these changes reduced operational risk and provided clearer error handling for file access scenarios.