Developed a configurable tool access control feature for the charmbracelet/crush repository, introducing the DisabledTools option to allow users to specify which agent tools should be inaccessible. The work involved refactoring backend tool management logic in Go to honor these restrictions while ensuring that default access remains unchanged when no tools are disabled. Comprehensive tests were added to verify that disabled tools are correctly excluded and that backward compatibility is maintained. This approach strengthened access policy enforcement and reduced operational risk, leveraging skills in backend development, configuration management, and testing to deliver a flexible solution that supports user-defined security requirements.