Brandrail

Your design system, in every AI coding tool.

AI coding tools don't know your design system, so every screen comes out with different colours, buttons and spacing. Brandrail's MCP server gives the tool your Brand Kit and components before it writes UI, then checks what it wrote and returns the fixes, so it corrects itself before you see the code.

• Seven read-only tools: get_guidelines, get_design_tokens, find_component, get_component_docs, get_template, get_migration_map, validate_snippet.

• Works in React, Angular, Vue, Web Components and plain HTML. The checker also reads Svelte, CSS, PHP, Twig, Mustache, Handlebars, Nunjucks and Liquid.

• Runs locally over stdio. Code is checked on your machine and never uploaded.

• Try it with no account: it starts with starter tokens. Connect a free Brandrail account to use your own Brand Kit.

Use it with your AI tool

In each repo:

npx brandrail connect

It signs you in through the browser and writes the MCP config and rule files for Claude Code, Cursor, Copilot, Codex, Windsurf and Gemini CLI. The files it writes hold no key, so commit them.

You type the code it shows on the Brandrail page, so nobody can approve a terminal for you with a link. The key is made on your machine (only its hash is sent) and saved outside the repo. To help you recognise the request, the terminal's description (user@computer · folder) is shown on the approval page.

Or add the MCP server by hand (works without an account):

{
  "mcpServers": {
    "brandrail": { "command": "npx", "args": ["-y", "brandrail", "mcp"] }
  }
}

Cursor install link:

cursor://anysphere.cursor-deeplink/mcp/install?name=brandrail&config=eyJjb21tYW5kIjoibnB4IiwiYXJncyI6WyIteSIsImJyYW5kcmFpbCIsIm1jcCJdfQ==

Set BRANDRAIL_KEY (an API key from Dashboard → Connect) to load your organisation's Brand Kit without running connect. Full docs: https://www.brandrail.com.au/docs/connect

BRANDRAIL_KEY is only ever sent to www.brandrail.com.au (or localhost). If BRANDRAIL_API_URL points anywhere else, the CLI says so on every run and won't send the key; sign in to that server with connect.

Related MCP server: Atelier-MCP

MCP tools

The CLI

The same package is a command-line checker:

npx brandrail check --changed          # only what you changed vs origin/main
npx brandrail scan http://localhost:3000 --pages 3   # a running app, in a real browser
npx brandrail migrate                  # what's left of Material, MUI, Bootstrap and others

Every command and option: packages/cli/README.md and https://www.brandrail.com.au/docs/cli

Privacy

The MCP server and CLI run on your machine. Code is checked locally and never uploaded. With a key, they fetch your Brand Kit; --upload and --report send scores and messages to your dashboard, never code. Security details: https://www.brandrail.com.au/security

What's in this repo

packages/
  cli/      the `brandrail` npm package: CLI and local MCP server
  mcp/      the MCP server's tools
  engine/   the checker rules engine (pure TypeScript, no runtime dependencies)
mcpb/       MCP bundle for Smithery and desktop apps
plugins/
  cursor/   Cursor plugin: MCP server plus a rule

pnpm install
pnpm test     # engine tests
pnpm build    # → packages/cli/dist/brandrail.mjs

Licence

MIT, see LICENSE. The Brandrail web app (Brand Kit hosting, repo sync, GitHub App, teams) is a separate service: https://www.brandrail.com.au/pricing

Questions: hello@brandrail.com.au · Security reports: security@brandrail.com.au