@verevoir/design-gate

The design substrate, in two layers:

• The gate (. → design/) — a zero-dependency deterministic verifier for a design pack: DTCG token validation, regenerate-diff of generated value views, and value-drift checks over the concept docs. Node built-ins only — runs anywhere with no install. The same code the design capabilities emit into a produced pack (for that pack's CI) and the runtime imports to enforce a capability's verify: design-pack postcondition (STDIO-451) — one source, two consumers.
• The surface (./surface → surface/surface.ts) — the typed DesignSurface contract (the design interlingua) with its validateSurface gate and merge/synthesise. Its token layer is validated by delegating to the gate's validateDtcg, so the tokens are the token-layer slice of one surface rather than a separate DTCG pipeline (STDIO-524). This layer is TypeScript and depends on zod; the gate stays zero-dependency and is what ships into packs.

Use

import { verifyFiles } from '@verevoir/design-gate';

// files: { path -> content } (e.g. read back from the branch the model wrote to)
const { ok, findings } = verifyFiles({
  'design-language/tokens/colour.tokens.json': '…',
  'design-language/tokens/colour.tokens.md': '…',
  'design-language/colour.md': '…',
});

verifyFiles(map) returns { ok, findings }; each finding is { kind, file?, where?, message } (kinds DTCG / VIEW_DRIFT / VALUE_DRIFT / NO_TOKENS / PARSE), model-actionable so an execution loop can re-prompt until green. The full surface (verifyPack, renderTokenView, validateDtcg, tokenLiterals, findValueDrift, runGate) and the check semantics are in design/README.md.