Worked on the Effect-TS/effect-smol repository to deliver OpenAPI Multipart File Upload support and improve tracing span linkage. Enhanced the OpenAPI schema generation to accurately represent multipart file uploads, updating tests to ensure correct behavior and interoperability for client integrations. Addressed an issue with tracing by ensuring nested spans are properly linked to their parent spans, which improved trace completeness and facilitated more effective debugging. Utilized TypeScript for both API development and testing, with a focus on tracing and observability. These contributions strengthened API reliability and internal monitoring, enabling smoother integration experiences and faster resolution of issues for users and developers.