DESIGN SYSTEMS NEED EVALS

Summary from the TLDR Design newsletter

Design systems have adopted software engineering practices, but agents generating code against these systems still can't be verified for compliance without dedicated evaluation suites. Effective evals combine mechanical checks—validating props, tokens, and component usage against the actual system—with LLM-based judgment on pattern selection and edge-case handling, run repeatedly since underlying models and rules keep shifting. While a few teams like Meta's Astryx and Intuit have begun building these regression suites into their pipelines, running such evals in CI remains an uncommon practice rather than a standard expectation.