Worked on stability and API contract improvements for Server-Sent Events (SSE) streaming in the hey-api/openapi-ts repository, focusing on a targeted bug fix to prevent errors from leaking through SSE iterators. Addressed a specific issue where errors could be exposed as iterator return types, clarifying the API contract and reducing the risk of mixed error and response types for downstream SDKs. Utilized TypeScript and applied principles of API design and SDK development to enhance code maintainability and developer experience. The work was delivered as a clear, single-purpose commit with descriptive messaging, ensuring reliable client integration and improved code quality.