Generate, refresh, and validate DESIGN.md files that capture a project's visual identity as machine-readable design tokens (YAML frontmatter) plus human-readable rationale (markdown prose), so AI agents generating new screens stay on-brand. Monorepo-aware — writes a global root DESIGN.md and per-workspace override DESIGN.md files that cascade (workspace overrides root). Validates with the official `@google/design.md` CLI (lint + diff). Use when the user wants to document or capture the visual design system / visual identity, create or refresh a DESIGN.md, establish design tokens for AI consumption, keep agents on-brand, lint a DESIGN.md, or mentions "DESIGN.md", "design tokens", or "visual identity". This is for documenting a visual identity into a DESIGN.md — NOT for code, function, or API documentation (use code-documenter), and NOT for refactoring code into shared components/tokens (use extract).
Identify reusable UI patterns, components, and design tokens, then extract and consolidate them into a design system for systematic reuse. Use when the user wants to extract, consolidate, or dedupe repeated components, hard-coded values (colors, spacing, typography, shadows), or composition patterns into shared design-system components or tokens — or mentions "extract", "reusable components", "design tokens", "consolidate UI", "pull into the design system", or "stop duplicating this component".