Extract Design

---
name: extract-design
description: >-
  Extract a complete design system — colors, typography, spacing, components, shadows, and W3C design tokens — from any live website using Dembrandt. Runs a headless browser against the URL and returns real computed values from the DOM. Use when you need a site's actual design tokens, want to reverse-engineer a visual design, or need to seed a design system from an existing product.
metadata:
  priority: 9
  requires: dembrandt>=0.23.1
  pathPatterns:
  - '**/tokens/**'
  - '**/theme/**'
  - tailwind.config.*
  - '**/design-system/**'
  - '**/*.css'
  - '**/*.scss'
  - '**/styles/**'
  promptSignals:
    phrases:
    - extract design
    - design tokens
    - reverse engineer
    - copy design
    - extract colors
    - extract typography
    - brand tokens
    - design system from
    - extract from website
    - dembrandt
    - what colors does
    - what fonts does
    - design of this site
retrieval:
  aliases:
  - extract design tokens
  - reverse engineer design
  - get colors from website
  - extract brand
  - design system extraction
  - dembrandt
  - copy design system
  intents:
  - extract design tokens from a live site
  - reverse engineer a website's visual design
  - seed a new design system from an existing product
  - get exact colors, fonts, and spacing from a URL
  - analyze a competitor's design system
  - generate tailwind config from a real site
  - generate shadcn theme from a real site
  examples:
  - extract the design system from stripe.com
  - what colors and fonts does linear.app use
  - reverse engineer vercel.com's design tokens
  - get the tailwind config for this site
  - copy the design system from this URL
  - what is the primary color of this website
---
# Extract Design — Dembrandt

Dembrandt runs a headless Chromium browser against any URL, walks up to thousands of DOM elements, reads computed CSS, and returns a structured design system: colors with confidence scoring, typography styles, spacing scale, border radius, borders, shadows, and interactive component styles.

## How to Run

```bash
# Zero-install — npx fetches the package on first run (lowest friction)
npx -y dembrandt https://stripe.com

# Or install once (global), then call `dembrandt` directly
npm i -g dembrandt

# Basic extraction — outputs to terminal
dembrandt https://stripe.com

# JSON output — pipe into files or other tools
dembrandt https://stripe.com --json-only > stripe-tokens.json

# W3C DTCG format (design-tokens.org standard)
dembrandt https://stripe.com --dtcg --save-output

# Generate DESIGN.md (human + AI readable brand doc)
dembrandt https://stripe.com --design-md

# Multi-page crawl (follows internal links)
dembrandt https://stripe.com --crawl 5

# Dark mode colors
dembrandt https://stripe.com --dark-mode

# Mobile viewport
dembrandt https://stripe.com --mobile

# Everything saved to output/
dembrandt https://stripe.com --save-output

# Self-contained HTML report — open offline or attach as a CI artifact  [dembrandt 0.19+]
dembrandt https://stripe.com --html report.html

# Drift gate — compare against a saved baseline; exits 1 on drift  [dembrandt 0.19+]
dembrandt https://app.example.com --compare baseline.json --html report.html
```

## MCP Usage (async by default)

To expose Dembrandt as MCP tools, add this server to the agent's MCP config (no install — `npx` fetches it on first run):

```json
{ "mcpServers": { "dembrandt": { "command": "npx", "args": ["-y", "--package", "dembrandt", "dembrandt-mcp"] } } }
```

When using the Dembrandt MCP server, all extraction tools return a `job_id` immediately rather than blocking. Poll `get_job_status` until `status` is `"completed"`:

```
1. get_design_tokens({ url: "stripe.com" })
   → { job_id: "job_123_abc", status: "queued" }

2. get_job_status({ job_id: "job_123_abc" })
   → { status: "running" }   // poll again

3. get_job_status({ job_id: "job_123_abc" })
   → { status: "completed", result: { ... } }
```

Pass `sync: true` to any extraction tool to block and return the result directly (useful on fast networks, risks timeout on slow sites).

Extraction tools: `get_design_tokens` (everything), `get_color_palette`, `get_typography`, `get_component_styles`, `get_surfaces`, `get_spacing`, `get_brand_identity`. All accept `slow`, `mobile` (mobile viewport), and `cookie` (cookie string for authenticated pages); `get_design_tokens` and `get_color_palette` also accept `darkMode` and `wcag` (contrast analysis).  [dembrandt 0.23.1+ for mobile/cookie/wcag]

Pure tools (no browser, synchronous, take an extraction object): `compute_drift` (0-100 drift score between two extractions), `get_findings` (design-system lint: contrast, consistency, duplication), `export_dtcg` (W3C Design Tokens format), `generate_design_md` (DESIGN.md brand guide), `render_report` (self-contained HTML report). Job control: `get_job_status`, `list_jobs`, `cancel_job`.  [dembrandt 0.23.1+ for get_findings/export_dtcg/generate_design_md/list_jobs]

Note: dembrandt <=0.23.0 fails to start via the npx one-liner above (`McpDepsMissingError`) — the MCP SDK was an optional peer dependency. Fixed in 0.23.1; require it.

## Output Structure

Dembrandt returns a structured object. The key sections:

```
colors.palette        — Deduplicated colors with confidence (high/medium/low)
colors.semantic       — Primary, secondary, background, text, and accent detection
colors.cssVariables   — Named CSS custom properties with LCH + OKLCH values
typography.styles     — Font family, size, weight, line-height per context
typography.sources    — Google Fonts, Adobe Fonts, variable font detection
spacing.commonValues  — Margin/padding scale with rem equivalents
spacing.scaleType     — 4px, 8px, or custom grid
borderRadius.values   — Border radius tokens with element context
borders.combinations  — Width + style + color combinations
shadows               — Box shadow elevation system
components.buttons    — Button variants with hover/active/focus states
components.inputs     — Input styles with focus states
components.links      — Link colors and hover states
components.badges     — Badge/tag/chip variants
breakpoints           — Responsive breakpoints from CSS media queries
frameworks            — Detected CSS framework (Tailwind, shadcn, MUI, etc.)
iconSystem            — Detected icon library (Heroicons, FA, Material, etc.)
```

## Working with Extracted Tokens

### Seeding a Tailwind config

After extraction, map the output to `tailwind.config.js`:

```js
// tailwind.config.js
export default {
  theme: {
    colors: {
      primary: '#hex-from-colors.palette[0]',
      // ...
    },
    fontFamily: {
      sans: ['Family from typography.styles', 'system-ui'],
    },
    spacing: {
      // Map spacing.commonValues px → rem
    },
    borderRadius: {
      // Map borderRadius.values
    },
    boxShadow: {
      // Map shadows
    },
  }
}
```

### Seeding a shadcn/ui theme

Map semantic colors to shadcn CSS variables in HSL:

```css
:root {
  --background: /* from colors.semantic.background (0.22.0+), else colors.palette — lightest neutral */;
  --foreground: /* from colors.semantic.text (0.22.0+), else colors.palette — darkest neutral */;
  --primary: /* from colors.semantic.primary */;
  --primary-foreground: /* contrasting color */;
  --muted: /* mid-tone neutral */;
  --border: /* from borders.combinations[0].color */;
  --radius: /* from borderRadius.values[0].value */;
}
```

### Reading confidence levels

Dembrandt scores every color by semantic context:

| Confidence | Meaning |
|---|---|
| **high** | Appears on semantically labeled elements (buttons, CTAs, headers with brand classes). Almost certainly a brand color. |
| **medium** | Moderate frequency or moderate context. Likely a brand color. |
| **low** | Rare, low semantic context. May be a one-off or component-specific color. |

Start with `high` confidence colors when building a palette. Include `medium` for full coverage. Treat `low` as reference only.

## Flags Reference

| Flag | What it does |
|---|---|
| `--json-only` | Clean JSON to stdout — pipe into files or tools |
| `--save-output` | Save JSON to `output/<domain>/<timestamp>.json` |
| `--dtcg` | W3C Design Tokens Community Group format |
| `--design-md` | Generate `DESIGN.md` — prose-first brand doc |
| `--html [path]` | Self-contained HTML report (inline CSS, embedded JSON). Open offline or attach as a CI artifact. *(0.19+)* |
| `--compare <baseline.json>` | Diff against a saved extraction; prints a drift verdict and exits `1` on drift. CI gate. *(0.19+)* |
| `--brand-guide` | Generate a PDF brand guide |
| `--dark-mode` | Extract dark color scheme and merge into palette |
| `--mobile` | Extract at 390px mobile viewport |
| `--crawl <n>` | Crawl up to N pages and merge tokens |
| `--sitemap` | Discover pages from sitemap.xml |
| `--slow` | 3× timeouts — use on slow-loading or JS-heavy sites |
| `--screenshot <path>` | Save a full-page screenshot |
| `--raw-colors` | Include pre-filter raw colors in JSON output |
| `--browser firefox` | Use Firefox instead of Chromium |
| `--stealth` | Opt-in anti-detection: navigator spoofing + human mouse simulation. Use only when authorized. |
| `--user-agent <string>` | Custom user agent string |
| `--locale <string>` | Browser locale, e.g. `fi-FI`, `en-GB` (default: `en-US`) |
| `--timezone <string>` | Browser timezone, e.g. `Europe/Helsinki` (default: `America/New_York`) |
| `--accept-language <string>` | Custom `Accept-Language` header value |
| `--screen-size <WxH>` | Physical screen resolution to report, e.g. `1920x1080` |

## Drift Detection & CI  *(dembrandt 0.19+)*

`--compare` turns extraction into a gate. Save a known-good baseline, then compare later extractions against it:

```bash
# 1. capture a baseline (in the SAME environment you will check against)
dembrandt https://app.example.com --json-only > baseline.json

# 2. later — compare; exits 0 if stable, 1 if drifted
dembrandt https://app.example.com --compare baseline.json --html report.html
```

- Runs the canonical drift engine over **structured tokens** — deterministic, not a pixel/render diff.
- **Exit code:** `0` stable, `1` drift. Gates a pipeline directly.
- `--html` writes a self-contained report; with `--compare` it includes a drift banner (added/removed/changed tokens). Attach it as a CI artifact.

**Determinism:** capture the baseline in the *same environment* you check it in (both production, or both the same preview). A baseline from one environment compared against another shows false drift.

**In CI:** run `--compare <baseline> --html report.html` against a preview/deployed URL, fail the job on exit `1`, upload the HTML artifact. **Programmatic:** import `computeDrift` from `dembrandt/drift` and `generateHtmlReport` from `dembrandt/report` to diff and render server-side without the CLI.

## Anti-Bot and SPA Handling

Dembrandt handles common extraction challenges automatically:

- **SPA hydration** — waits 8s for React/Vue/Svelte to render before extracting
- **Lazy content** — scrolls the full page to trigger lazy-loaded components
- **Cloudflare / bot walls** — auto-retries with a visible browser if headless is blocked
- **Slow sites** — use `--slow` for 3× timeouts on heavy JS bundles
- **Cookie banners** — dismisses common CMP dialogs (OneTrust, cookielaw, GDPR patterns) automatically
- **Bot detection bypass** — use `--stealth` to opt in to navigator spoofing and human mouse simulation; off by default so the tool identifies itself honestly

## Checklist After Extraction

- [ ] Identify the 3–5 high-confidence colors — these are the core brand palette
- [ ] Check `colors.semantic.primary` — is it correct?
- [ ] Look at `typography.styles` — what are the heading and body fonts?
- [ ] Check `spacing.scaleType` — 4px or 8px grid?
- [ ] Review `components.buttons` — how many variants exist?
- [ ] Check `frameworks` — is Tailwind, shadcn, or MUI detected? This shapes how you apply the tokens.
- [ ] Use `--dark-mode` if the site has a dark theme
- [ ] Use `--crawl 3` if the site has a multi-section design system spread across routes