Marais developed robust evaluation tooling and flexible UI components across the github/gh-models and primer/react repositories. In github/gh-models, Marais introduced template-based string evaluators that dynamically assess conditions like equals and contains using test-case data, enhancing test coverage and reliability. The evaluation workflow was improved to fail fast by exiting with a non-zero status on test failures, streamlining error handling and triage. In primer/react, Marais expanded the UnderlineNav component with new 'inset' and 'flush' variants, updating props, Storybook examples, and CSS Modules for richer UI alignment options. The work demonstrated depth in Go, React, and testing practices.