Stitch::extract Static Html

Extract Static HTML

Extract a self-contained static HTML file from any web application.

Which Strategy to Use

You MUST ask the user to choose which strategy to use before proceeding. Present the options clearly, recommend Strategy A as the preferred default, and provide a brief pros/cons summary for each option to help them make an informed decision.

| | Strategy A (Puppeteer) | Strategy B (Browser Subagent) | | :--- | :--- | :--- | | When | App runs locally, no auth wall | Need to interact with page first (click, fill forms) | | Fidelity | Highest — computed styles resolved | High — rendered DOM | | Setup | Zero — no mock needed | Zero — no mock needed | | Framework | Any | Any | | Output | Writes to file — no size limit | May truncate in agent context |

> [!WARNING] > Checkpoint — User Confirmation Required. > You MUST ask the user which strategy they prefer before proceeding. > Present the comparison table above, recommend Strategy A as the default, and > wait for explicit approval. Do NOT make the decision yourself or proceed > until the user confirms.

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Strategy A: Puppeteer Snapshot (Recommended)

Launches headless Chrome, captures the fully rendered DOM, and produces a self-contained HTML file with all CSS inlined and images as base64. Works with any framework — no MockPage.jsx needed.

Prerequisites

• App running locally (e.g., npm run dev)
• Node.js with puppeteer available (check: node -e "require('puppeteer')")

Workflow

1. Start the App and note the port.

> [!WARNING] > Checkpoint — User Confirmation Required. > After starting the local server, you MUST pause and ask the user for > confirmation before running the snapshot script or launching a browser > subagent. Report the URL and port to the user so they can verify the app > is running and rendering correctly. Do NOT proceed to the snapshot > step until the user confirms.

1. Run the Snapshot Script:

``bash npx tsx /scripts/snapshot.ts \ --url http://localhost:5173 \ --output .stitch/home.html \ --wait 2000 ``

1. Multiple pages — run once per route:

``bash npx tsx /scripts/snapshot.ts \ --url http://localhost:5173 --output .stitch/home.html --wait 2000 npx tsx /scripts/snapshot.ts \ --url http://localhost:5173/pricing --output .stitch/pricing.html --wait 2000 npx tsx /scripts/snapshot.ts \ --url http://localhost:5173/dashboard --output .stitch/dashboard.html --wait 2000 --html-class dark ``

Script Flags

| Flag | Default | Description | | :--- | :--- | :--- | | --url | (required) | URL to capture | | --output | (required) | Output file path | | --wait | 1000 | Extra wait (ms) after network idle. Increase for lazy-loading apps. | | --viewport | 1280x800 | Viewport size as WIDTHxHEIGHT | | --html-class | — | Class(es) for ` element (e.g., dark) | | --remove-fixed | false | Remove fixed/sticky elements (cookie banners, chat widgets) | | --full-height | false | Resize viewport to full scroll height | | --title` | — | Override page title |

What It Does Automatically

• Inlines all ` → ` blocks
• Converts ` src **and srcset`** → base64 data URIs (skips fonts)
• Inlines `` URLs as base64
• Removes failed/dead srcset entries so the browser falls back to the inlined src
• Removes `` tags, Vite overlay, Next.js dev indicators
• Resolves relative CSS url() paths before inlining

Framework Notes

| Framework | Notes | | :--- | :--- | | React + Vite | Works out of the box. --wait 1000. | | Next.js | --wait 3000 for SSR hydration. URL: http://localhost:3000. ` from /_next/image is auto-inlined as base64. | | **Vue / Nuxt** | Works out of the box. | | **Svelte / SvelteKit** | Works out of the box. | | **Storybook** | Use story URL: --url http://localhost:6006/?path=/story/... | | **SSR (Webpack)** | May need longer --wait`. |

Troubleshooting

| Issue | Solution | | :--- | :--- | | Images missing | Increase --wait | | Images show as broken after server stops | Verify srcset was inlined — check log for "Inlined N images". If srcset URLs failed, they are auto-removed so src (inlined) is used. | | Next.js /_next/image not inlined | Ensure the dev server is running when snapshot runs — the script fetches optimized images from the running server. | | Dark mode not applied | --html-class dark | | Cookie banner in output | --remove-fixed | | Page requires login | Use the Static Fallback (appendix below) | | Cannot find module 'puppeteer' | npm install -g puppeteer |

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Strategy B: Browser Subagent Capture

Use when you need to interact with the page (click buttons, fill forms, navigate tabs) before capturing. The browser subagent gives you full control but output may truncate for large pages.

Workflow

1. Start the App locally.
2. Navigate using a browser subagent.
3. Interact as needed (click, scroll, fill forms).
4. Extract DOM: document.documentElement.outerHTML

> [!WARNING] > Large pages may truncate. To handle this: > - Remove ` tags before extraction: document.querySelectorAll('style').forEach(el => el.remove())` > - Re-add styles statically (Tailwind CDN link, source CSS)

1. Save to file.

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Appendix: Static Fallback (MockPage.jsx)

> [!NOTE] > This method is a last resort for when the app cannot run locally (broken deps, missing backend, auth walls with no bypass). It requires manually flattening React components into a single JSX file. Prefer Strategy A whenever possible.

When to Use

• App can't run locally at all
• Page requires auth with no mock/bypass
• You need a specific UI state that's impossible to reach by navigation (error screens, empty states)

Quick Reference

npx tsx /scripts/extract_inline_html.ts \
  --index-css src/css/App.css \
  --extra-css index.html \
  --outdir .stitch \
  --page src/MockPage.jsx:Page.html:"Page Title"

Key flags: --no-tailwind (non-Tailwind apps), --html-class dark (dark mode), --css-files (extra CSS files).

Auto-detection: Tailwind config is auto-detected. @apply directives automatically use ``.

MockPage.jsx Rules

1. Include the full layout — header, sidebar, footer (read App.js first)
2. Flatten all conditionals — pick one state, remove all ternaries and && guards
3. Hardcode all data — replace {variable} with concrete values, unroll .map() loops
4. Preserve logos — use `` with local paths (post-process will inline them)
5. Remove floating elements — cookie banners, chat widgets, feedback buttons

Post-Processing

Inline local images:

npx tsx /scripts/post_process.ts \
  .stitch/Page.html --base-dir 

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: google-labs-code
• Source: google-labs-code/stitch-skills
• License: Apache-2.0
• Homepage: https://stitch.withgoogle.com/docs/mcp/setup

Install and usage instructions live in the source repository linked above.