design-system

Builds a provided design system into named tokens, a UI library in the target stack's idiom, a verifiable preview page, and three registrations (doc, AGENTS.md reference, project UI skill) — so every later UI change reuses the library instead of inlining one-off markup. Run once per UI project after /agents-md → /setup-matt-pocock-skills → placeholder fill; re-run extend when a trigger fires.

Not this skill. One page matching its design pixel-for-pixel is /pixel-audit; cosmetic QA tails are /polish-batch; porting UI from a reference stack is /port-feature; tracing existing UI is /feature-discovery.

Inputs

Infer from the request and cheap repo evidence; interview only for gaps:

• TARGET PROJECT-CODE — the full Project Matrix code; it determines the output idiom. Project Matrix missing → stop and route to /agents-md first. Read the target's stack from the matrix / AGENTS.md, never guess it.
• DESIGN-SYSTEM SOURCE (required) — the named source wins. When none is named, load references/source-selection.md and follow its ordered discovery. A source with tokens remains their single source of truth. No source or explicitly approved guided definition → stop and ask; never fabricate a system.

Rules