Puppeteer

Setup

On first use, read setup.md for integration guidelines.

When to Use

User needs browser automation: web scraping, E2E testing, PDF generation, screenshots, or any headless Chrome task. Agent handles page navigation, element interaction, waiting strategies, and data extraction.

Architecture

Scripts and outputs in ~/puppeteer/. See memory-template.md for structure.

~/puppeteer/
├── memory.md       # Status + preferences
├── scripts/        # Reusable automation scripts
└── output/         # Screenshots, PDFs, scraped data

Quick Reference

Core Rules

1. Always Wait Before Acting

Never click or type immediately after navigation. Always wait for the element:

await page.waitForSelector('#button');
await page.click('#button');

Clicking without waiting causes "element not found" errors 90% of the time.

2. Use Specific Selectors

Prefer stable selectors in this order:

1. [data-testid="submit"] — test attributes (most stable)
2. #unique-id — IDs
3. form button[type="submit"] — semantic combinations
4. .class-name — classes (least stable, changes often)

Avoid: div > div > div > button — breaks on any DOM change.

3. Handle Navigation Explicitly

After clicks that navigate, wait for navigation:

await Promise.all([
  page.waitForNavigation(),
  page.click('a.next-page')
]);

Without this, the script continues before the new page loads.

4. Set Realistic Viewport

Always set viewport for consistent rendering:

await page.setViewport({ width: 1280, height: 800 });

Default viewport is 800x600 — many sites render differently or show mobile views.

5. Handle Popups and Dialogs

Dismiss dialogs before they block interaction:

page.on('dialog', async dialog => {
  await dialog.dismiss(); // or dialog.accept()
});

Unhandled dialogs freeze the script.

6. Close Browser on Errors

Always wrap in try/finally:

const browser = await puppeteer.launch();
try {
  // ... automation code
} finally {
  await browser.close();
}

Leaked browser processes consume memory and ports.

7. Respect Rate Limits

Add delays between requests to avoid blocks:

await page.waitForTimeout(1000 + Math.random() * 2000);

Hammering sites triggers CAPTCHAs and IP bans.

Common Traps