DESIGN.md Skill

DESIGN.md is Google's open spec (Apache-2.0, google-labs-code/design.md) for describing a visual identity to coding agents. One file combines:

• YAML front matter, machine-readable design tokens (normative values)
• Markdown body, human-readable rationale, organized into canonical sections

Tokens give exact values. Prose tells agents why those values exist and how to apply them. The CLI (npx @google/design.md) lints structure + WCAG contrast, diffs versions for regressions, and exports to Tailwind or W3C DTCG JSON.

When to use this skill

• User asks for a DESIGN.md file, design tokens, or a design system spec
• User wants consistent UI/brand across multiple projects or tools
• User pastes an existing DESIGN.md and asks to lint, diff, export, or extend it
• User asks to port a style guide into a format agents can consume
• User wants contrast / WCAG accessibility validation on their color palette

For purely visual inspiration or layout examples, use popular-web-designs instead. For process and taste when designing a one-off HTML artifact from scratch (prototype, deck, landing page, component lab), use claude-design. This skill is for the formal spec file itself.

File anatomy

---
version: alpha
name: Heritage
description: Architectural minimalism meets journalistic gravitas.
colors:
  primary: "#1A1C1E"
  secondary: "#6C7278"
  tertiary: "#B8422E"
  neutral: "#F7F5F2"
typography:
  h1:
    fontFamily: Public Sans
    fontSize: 3rem
    fontWeight: 700
    lineHeight: 1.1
    letterSpacing: "-0.02em"
  body-md:
    fontFamily: Public Sans
    fontSize: 1rem
rounded:
  sm: 4px
  md: 8px
  lg: 16px
spacing:
  sm: 8px
  md: 16px
  lg: 24px
components:
  button-primary:
    backgroundColor: "{colors.tertiary}"
    textColor: "#FFFFFF"
    rounded: "{rounded.sm}"
    padding: 12px
  button-primary-hover:
    backgroundColor: "{colors.primary}"
---

## Overview