Michiel focused on improving test infrastructure for the scalar/scalar repository by enhancing error handling and documentation. He addressed a recurring issue where unclear error messages appeared when test servers were not running during test execution. By refining these messages in the TypeScript codebase, Michiel reduced debugging time and confusion for developers working with the api-client and oas-utils packages. He also updated documentation to ensure alignment with current CONTRIBUTING.md guidance, reinforcing consistency across the project. His work emphasized robust testing practices and clear communication, supporting more predictable CI outcomes and smoother onboarding for contributors through targeted improvements in error messaging and documentation.