ColorwayKit

ColorwayKit for Agents

Give your AI coding agent a brand's color system it can actually follow.

ColorwayKit turns one brand color into a complete, accessible light & dark web theme — 23 semantic roles, WCAG 2.1 + APCA contrast checks, and exports you can paste straight into a project.

• Website: https://www.colorwaykit.com
• Build a theme and export it: https://www.colorwaykit.com/brand

The problem this solves

Coding agents write working UI but invent colors: a blue button here, a different grey there, and a contrast ratio nobody checked. Re-describing your palette in every prompt doesn't scale.

DESIGN.md is an open format, adopted by AI coding tools, that puts a design system in one plain-text file: YAML design tokens (machine-readable values) plus a Markdown body (when and why to use them). Drop it in your project root and the agent reads it instead of guessing.

This repository collects the templates and an example we generate with ColorwayKit, so you can wire that file into the agents you already use.

Two ways to feed your agent

Both are free with a ColorwayKit account. Pick one, or use files as the versioned source and MCP as the live interface.

Option A: MCP server (live)

1. Create a free account at colorwaykit.com, then My Projects → Agent tab → Generate token.
2. Connect (Claude Code example):

   claude mcp add --transport http colorwaykit https://www.colorwaykit.com/api/mcp --header "Authorization: Bearer ck_YOUR_TOKEN"

1. Ask your agent: *"list the color tokens for #4F46E5"* — if it replies with named roles and measured contrast numbers, you are connected. Full setup for Cursor / Codex / Gemini CLI: https://www.colorwaykit.com/mcp

Tools: get_theme (one hex → full verified light & dark theme), check_pair (validate any text/background pair on the fly), get_theme_by_project (your saved cloud project), list_projects (enumerate your saved projects, newest first).

Option B: the file way (quick start)

1. Open the Brand Theme Engine and paste your brand hex (from your logo or guidelines).
2. Go to the Take it to dev tab and copy or download DESIGN.md. It is a free export format, alongside CSS variables, Tailwind config, Tokens Studio JSON and W3C DTCG tokens.
3. Save it as DESIGN.md in your project root.
4. Point your agent at it — see templates/.

What the exported file contains

• colors in YAML front matter: semantic roles for both themes (primary, on-primary, surface, on-surface, outline, error, …), with dark-theme roles prefixed dark-.
• components that reference those colors with {colors.x} syntax, so one change propagates.
• A Markdown Colors section listing a measured result for every text/background pair: WCAG 2.1 ratio against its threshold, plus APCA Lc against the use-case threshold. Pairs that fail are marked as failing — the file reports what the tool computed, nothing more.
• typography, rounded and spacing are declared omitted: the color engine has no measured values for them, so they stay with your framework's defaults rather than being invented.

See examples/DESIGN.md — generated from the brand color #4F46E5 by ColorwayKit, not hand-written.

Templates

Each template only describes how to consume DESIGN.md. Copy one into your project and adapt the paths. Every template now ships with an executable verification step — see below.

Verify with the linter (CLI)

Keep new colors honest with the companion checker — wild-color scan plus WCAG 2.1 pair validation, exit codes for CI. It ships in this repo — runs with Node 18+, no install:

node cli/index.js --tokens DESIGN.md --target .

Exit 0 = clean; exit 1 = wild hex values or failing pairs. Add --apca to also report APCA Lc per pair. Source lives in cli/ — wire it into a CI step so new colors go through the file first.

Already have extracted colors?

If you came from a DevTools inspection or an extraction tool, your hex list has no roles and no measurements yet. The migration guide walks it the last mile: docs/migration-extracted-css.md — raw hex → semantic roles → measured pairs → a formal DESIGN.md, with a real worked example (including a pair that genuinely fails).

FAQ

Where do the templates live? In this repository — free to copy. The DESIGN.md format itself is specified by Google Labs (Apache-2.0).

Do they work outside Claude Code? Yes. Templates are plain Markdown: .cursorrules for Cursor, AGENTS.md for Codex and most agents, SKILL.md for skill-aware clients.

Do I need both a skill and the MCP server? They compose. The file is the versioned contract your team ships; MCP is the live measurement tool that validates pairs and pulls freshly tuned themes on demand.

Is everything free? The templates, the Brand Theme Engine and the contrast checker are free. The MCP server is metered per account: Free 5 calls/day, Plus 1,000/month, Pro unlimited.

Notes and limits

• DESIGN.md is specified by Google Labs and licensed Apache-2.0 at google-labs-code/design.md. ColorwayKit is not the spec's author — we export to it.
• The specification is at an early version and describes parts of itself as evolving; component token structures may change.
• Contrast values are computed automatically and are a design reference, not a formal accessibility certification.
• The ColorwayKit engine covers color. Fonts, spacing and radii in the generated file are yours to define.

License

The templates and example in this repository are provided for practical use in your own projects. The DESIGN.md format itself is governed by its own specification and license (see the link above).