Worked on the o1-labs/o1js repository to deliver a comprehensive refactor of ZkProgram type definitions, focusing on enhancing type safety and maintainability for smart program development. The approach centralized type inference and introduced new type aliases, addressing correctness issues and improving clarity throughout the codebase. By replacing inline types with defined inferring types, the work streamlined the type system and laid a foundation for future extensibility. Utilizing TypeScript and advanced type system techniques, the changes improved the reliability of zero-knowledge proof program definitions. The effort emphasized code clarity and correctness, contributing to a more robust and future-proof codebase.