What is a design skill

A design skill is a folder with a markdown file in it. The file tells your AI coding agent how to design.

Agents are good at writing code and bad at taste. Left alone they produce the same page every time: a purple gradient, Inter, three cards, a big rounded button. A design skill replaces that default with a specific look. Which typeface. Which spacing scale. Which colours. What motion. What never to do.

The file is called SKILL.md. It has a short header saying what the skill is and when to use it, then the actual instructions. Your agent reads the header, decides the skill is relevant, loads the rest, and builds in that style.

What is inside one

Most design skills contain some mix of these.

• A named look, so the agent has something to aim at.
• Exact values. Font stacks, hex codes, spacing steps, radii, shadow recipes.
• Page structure. What sections a page needs and in what order.
• Rules about what to avoid. This is the part that does the most work.
• Sometimes reference files, code snippets or scripts alongside the markdown.

Which tools read them

Claude Code, Codex, Cursor, Windsurf, Gemini CLI and roughly twenty other agents read the same format. A skill written for one usually works in the others with no changes. That is the whole point of the format existing.

SKILL.md and DESIGN.md are not the same thing

SKILL.md is a capability. The agent loads it when the job calls for it, and ignores it otherwise. You can have hundreds installed.

DESIGN.md is a description of how your product looks. You put one in your project root and the agent reads it every time so that everything it builds matches what is already there. Google Labs published the format and it spread fast.

You want both. A design skill to get a good look in the first place, a DESIGN.md so the next thing you build still matches it.

Are they free

Everything in this catalogue is open source, and most of it is MIT licensed. Check the licence on the source repo before shipping commercial work. The people who wrote these gave them away, so credit them.