Worked on the firecracker-microvm/firecracker repository to address API correctness for balloon hinting endpoints by updating the OpenAPI specification. Focused on ensuring that PATCH requests to /balloon/hinting/start and /balloon/hinting/stop accurately documented 204 No Content responses, aligning the API documentation with actual server behavior. This change, implemented using YAML and leveraging skills in OpenAPI and Swagger, reduced integration risk and improved reliability for downstream clients. The update clarified REST semantics by mapping server responses to VmmData::Empty, preventing client misinterpretation. The work emphasized documentation accuracy, code-review traceability, and contributed to a better developer experience through precise API design.