Create new DESIGN.md files from a brand brief or aesthetic description, and update existing DESIGN.md files coherently. DESIGN.md is Google Labs' open format for describing a design system to AI coding agents — YAML token frontmatter plus markdown rationale. Use whenever the user mentions "DESIGN.md", a design system file, design tokens for a project, or asks to capture a project's visual identity in a portable format. Also trigger when the user wants to derive a design system from an existing brand (logo, website, brief) into a structured form an agent can read, or when they want to update the colors, typography, or components of a project's existing DESIGN.md. Do not trigger this skill for generating UI code itself (React, HTML, components) — that is a separate concern handled by frontend-design or similar skills. This skill produces and modifies the DESIGN.md file; other skills consume it.
One sentence about what it does AND when the agent should use it. Include trigger keywords.