Worked on the moltbot/moltbot repository to enhance backend stability and maintainability, focusing on the handling of working directories. Addressed a critical bug by implementing fail-fast validation for invalid explicit workdirs, ensuring that execution halts early and provides clearer error feedback when misconfigurations occur. Centralized the logic for workdir resolution, which reduced edge cases and simplified future updates. Hardened the backend contract by adding mappings for missing host workdirs and expanded regression testing to cover invalid scenarios using both real and temporary directories. Utilized TypeScript for backend development and testing, emphasizing robust error handling and safer cross-environment operations.