Make design guidance discoverable and enforce shared decisions

AGENTS.md

@@ -12,6 +12,14 @@ before live use.
 Files marked `FOUNDATION` require explicit human guidance before editing and
 stricter review. Escalate needed changes rather than editing without authorization.
 
+## Design-system instruction discovery
+
+Before any UI styling, component, token, appearance or viewer work anywhere in
+this repository, read [the canonical design-system rules](src/shared/design-system/AGENTS.md).
+This includes feature consumers, `tests/fixtures/design-system/`, its HTML entry,
+and `scripts/design-system/`; directory inheritance alone does not cover them.
+Follow its decision-specific references before changing a design decision.
+
 ## Engineering standard
 
 Before editing, state the intended outcome and non-goals. Read the owning code,

package.json

@@ -29,7 +29,7 @@
     "design:build": "pnpm design:typecheck && vite build --config vite.design.config.ts",
     "design:preview": "vite preview --config vite.design.config.ts",
     "design:typecheck": "tsc -p tsconfig.design.json",
-    "design:check": "node scripts/design-system/check-type.mjs && node scripts/design-system/check-color.mjs && node scripts/design-system/check-contrast.mjs",
+    "design:check": "node scripts/design-system/check-type.mjs && node scripts/design-system/check-color.mjs && node scripts/design-system/check-contrast.mjs && node scripts/design-system/check-authoring.mjs",
     "design:census": "node scripts/design-system/token-consumers.mjs",
     "design:test": "vitest run --config vitest.design.config.ts",
     "design:test:browser": "pnpm build && pnpm design:build && playwright test --config tests/fixtures/design-system/playwright.config.ts"

scripts/design-system/AGENTS.md

@@ -0,0 +1,5 @@
+# Design-system tooling instructions
+
+Read [the canonical design-system rules](../../src/shared/design-system/AGENTS.md)
+before changing enforcement. Checks verify mechanics and recorded decisions,
+not whether human design judgment is correct.