A design system fails at handoff when tokens are ambiguous and component APIs accept infinite variants. We define semantic tokens first — surface, border, accent — and map brand colors into that layer.
Component APIs get one primary action per surface. Secondary actions are explicit props, not style overrides. That constraint keeps Figma and code aligned when three squads ship in parallel.
Documentation is part of the component definition: usage do/don’t, accessibility notes, and responsive behavior screenshots ship with every merge.
Governance is lightweight: a weekly 30-minute review of new patterns, a changelog in the repo, and Storybook as the contract between design and engineering.
Drift is caught early when designers and engineers pair on the first consumer of any new primitive.
