DesignScan MCP Server

DesignScan

URL → design tokens → DESIGN.md. Point it at any website and get a spec-compliant DESIGN.md file (YAML tokens + prose) that AI coding agents can read to match that site's look.

Preview

Every run can also emit a self-contained HTML proof sheet (--preview) that renders the extracted tokens — color roles, type specimens, spacing/radius scales, components — so you can eyeball the result before trusting it:

Notes for your coding agent

A DESIGN.md is always consumed by an AI coding agent (Cursor, Claude Code, …). So rather than run our own LLM to resolve semantic intent, every file ends with a Notes for your coding agent section: deterministic, per-extraction instructions computed from the actual tokens — heading hierarchy vs. a muted text color, sub-AA body contrast, brand-font fallback, the primary-button contract, shape/spacing rhythm. The reasoning stays on our side (no API key); the application happens for free inside the agent you already use.

It measurably changes the output. Below: the same stripe.DESIGN.md cloned by an agent that ignored the notes (left) vs one that followed them (right) — identical tokens, layout, and copy:

Brand corpus

A growing, curated library of real-brand specs lives in examples/ — each one a DESIGN.md, an HTML preview, and the raw token JSON, indexed in examples/README.md (visual gallery: index.html).

Rebuild it from the committed JSON with pnpm seed rebuild (no network), or add brands with pnpm seed add <url> — degenerate / bot-challenged pages are skipped automatically so the corpus only holds trustworthy specs.

Monorepo layout

Install (as a CLI / library)

The engine ships as the publishable @designscan/extractor package — a designscan CLI and a typed library.

# one-off, no install
npx @designscan/extractor stripe.com --md --out stripe.DESIGN.md

# or install the CLI
npm i -g @designscan/extractor
npx playwright install chromium   # one-time (the engine drives headless Chromium)
designscan stripe.com --md --preview --out stripe.DESIGN.md

Quick start (from this repo)

This is a pnpm workspace (corepack enable to get pnpm).

pnpm install
pnpm --filter @designscan/extractor exec playwright install chromium  # one-time

# token profile (JSON) for any URL
pnpm extract stripe.com

# generate a DESIGN.md (light theme by default)
pnpm extract stripe.com --md --out out/stripe.DESIGN.md

# pick a theme: light (default) | dark | both
pnpm extract vercel.com --md --theme dark --out out/vercel.dark.DESIGN.md

# both = bundle light + dark into one file (parallel *-dark tokens)
pnpm extract vercel.com --md --theme both --out out/vercel.DESIGN.md

# --preview = also write a self-contained HTML proof sheet beside the file,
# rendering every token (swatches, type specimens, scales, components) so you
# can eyeball the extraction before trusting it (--theme both adds a Light/Dark toggle)
pnpm extract stripe.com --md --preview --out out/stripe.DESIGN.md
# → out/stripe.DESIGN.md  +  out/stripe.preview.html

# --format = pick your output: json (profile) | md (DESIGN.md) | w3c | css
pnpm extract stripe.com --format w3c --out out/stripe.tokens.json  # W3C Design Tokens (Style Dictionary etc.)
pnpm extract stripe.com --format css --out out/stripe.tokens.css   # CSS custom properties, paste-ready
# (--theme both folds a genuinely distinct dark pass into every format)

# --strict = exit non-zero if the result looks degenerate (bot challenge / too
# few signals), for CI/automation that must not consume junk tokens
pnpm extract stripe.com --strict --quiet

# seed / rebuild the curated brand corpus under examples/
pnpm seed add tailwindcss.com vercel.com   # extract live + add to the corpus
pnpm seed rebuild                          # regen md/preview/gallery from JSON

Scripts (root)

All of these run on every push/PR via GitHub Actions. The engine is consumable as a library through its public API (packages/extractor/src/index.ts).

Status

• Step 1 — Extraction engine (Playwright → clean token profile)
• Step 2 — Generator (token profile → spec-valid DESIGN.md, lint-clean)
• Step 3 — HTML preview (--preview → self-contained token proof sheet, light/dark toggle)
• [~] Step 4 — agent guidance. Each DESIGN.md now ships a Notes for your coding agent section: deterministic, per-extraction instructions (contrast, heading hierarchy, font fallback) so the consuming agent applies the tokens with intent — no LLM on our side. (Optional LLM-refined prose still future.)
• [~] Step 5 — brand-seed library (pnpm seed, curated corpus + gallery) done; npx … add / checkout next

See packages/extractor/README.md for the full roadmap and engine details.