Developed an enhanced OpenAI Chat Completions API integration for the 0xPlaygrounds/rig repository, focusing on flexible output formats and robust schema validation. Leveraging Rust and API development expertise, introduced support for emitting tool results as either strings or arrays, with strict schema validation to ensure compatibility with OpenAI requirements. Core data models were refactored to support these changes, maintaining backward compatibility and improving serialization for diverse output types. Refactored shared logic to improve code maintainability and developer ergonomics. This work reduced API incompatibilities, enabled richer tool-result representations, and improved the reliability and flexibility of OpenAI integration within the codebase.