Worked on LibreChat to enhance the reliability of continuous integration by addressing a critical issue with Winston format factory mocks in Jest, ensuring compatibility with data-schemas contracts. The solution involved restoring the mock’s shape to accurately reflect Winston’s real API, returning a thunk that yields the expected transform function. Extended the mock surface to include the full format namespace, addColors, and transports such as DailyRotateFile and File, aligning tests and mocks with production usage. Used JavaScript and focused on mocking and testing, which eliminated runtime module-load errors and improved CI stability without altering production behavior. Collaborated closely with another contributor.