Worked on the vitest-dev/vitest repository to deliver enhanced annotation encoding and data type support, focusing on robust handling of binary payloads within the test annotation system. Addressed encoding edge-cases by implementing proper Uint8Array body encoding and introducing support for base64 and content type metadata, which improved data fidelity and reduced test flakiness. Leveraged TypeScript and front end development skills to integrate these changes seamlessly into the test runner, expanding the range of supported test scenarios involving binary data. The work demonstrated careful attention to repository standards and effective collaboration with maintainers, contributing to more reliable and flexible testing workflows.