Ben contributed to the martinvonz/jj repository by developing Workspace Restore Validation Warnings, a feature that proactively alerts users when attempting to restore to an operation where the current workspace is missing. This addition, implemented in Rust, focused on improving the reliability and user guidance of the restore workflow by preventing invalid operations and reducing confusion. Ben applied test-driven development practices, creating automated tests to ensure robust validation and resilience. The work emphasized clear UX messaging and thorough workflow validation, demonstrating skills in Rust programming, command line interface development, and testing. The feature addressed a concrete usability issue and improved workflow integrity.