DESIGN.md (format)
Open format released by Google Labs (Apache 2.0, April 21 2026) combining YAML front-matter (machine-readable tokens: colors, typography, spacing, radius) + Markdown body (human rationale) in a single `DESIGN.md` file at the repo root. Coding agents (Claude Code, Cursor, Antigravity, Gemini CLI) read it automatically to generate UI consistent with brand identity.
Strengths
- Open Apache 2.0 standard, no lock-in, supported by Claude Code / Cursor / Antigravity / Gemini CLI
- Native export to Tailwind + DTCG (tokens.json W3C), pivots into existing pipelines
- Built-in validation: broken token references, WCAG contrast ratios, structured JSON agents can consume
Limitations
- Still in alpha (CLI and schema under active development), breaking changes possible before v1
- DESIGN.md is a textual approximation, does not replace Figma as the human source of truth for design exploration
Best for
- Teams who want their AI agents to generate UI consistent with their brand without repeating guidelines every session
- Design system managers who need to propagate visual identity across multiple products/devices with one agent-readable source of truth