Hyunjin worked on the promptfoo/promptfoo repository, focusing on stabilizing the Excel test data ingestion pipeline. By addressing issues with array format handling and sheet specifier parsing, Hyunjin improved the reliability of loading test cases from Excel files, which reduced test setup failures and minimized flaky test runs. The solution involved targeted TypeScript development and comprehensive testing to ensure robust data processing. After completing code review and CI validation, the patch was merged to main, providing end-to-end verification. Hyunjin also enhanced commit messages and issue linkage, supporting better traceability and future audits within the full stack development workflow.