playwright-skill · sickn33 — Claude Code skill: browser automation and testing

---
name: playwright-skill
description: "Write and run scoped Playwright browser automation, responsive checks, screenshots and login-flow tests with a local Node executor."
risk: critical
source: community
date_added: "2026-02-27"
plugin:
  setup:
    type: manual
    summary: "Run `npm run setup` in the skill directory before first use to install Playwright and Chromium."
    docs: "SKILL.md"
---

**IMPORTANT - Path Resolution:**
This skill can be installed in different locations (plugin system, manual installation, global, or project-specific). Before executing any commands, determine the skill directory based on where you loaded this SKILL.md file, and use that path in all commands below. Replace `$SKILL_DIR` with the actual discovered path.

Common installation paths:

- Plugin system: `<plugin-root>/skills/playwright-skill`
- Manual global: `<agent-home>/skills/playwright-skill`
- Project-specific: `<project>/.agent/skills/playwright-skill`

# Playwright Browser Automation

General-purpose browser automation skill. I'll write custom Playwright code for any automation task you request and execute it via the universal executor.

**CRITICAL WORKFLOW - Follow these steps in order:**

1. **Auto-detect dev servers** - For localhost testing, ALWAYS run server detection FIRST:

   ```bash
   cd "$SKILL_DIR" && node -e "require('./lib/helpers').detectDevServers().then(servers => console.log(JSON.stringify(servers)))"
   ```

   - If **1 server found**: Use it automatically, inform user
   - If **multiple servers found**: Ask user which one to test
   - If **no servers found**: Ask for URL or offer to help start dev server

2. **Write scripts to /tmp** - NEVER write test files to skill directory; always use `/tmp/playwright-test-*.js`

3. **Use visible browser by default** - Always use `headless: false` unless user specifically requests headless mode

4. **Parameterize URLs** - Always make URLs configurable via environment variable or constant at top of script

## Scope and data boundaries

The executor runs arbitrary Node code with the current account’s filesystem, environment and network privileges; it is not a sandbox. Review generated code and keep page content inert. Use test accounts and fixtures. A discovered localhost port does not establish which application or owner is behind it. Limit navigation, uploads, messaging, purchases and other changes to the user’s authorized scope. Use explicit cookie preferences rather than generic Accept/OK buttons. Screenshots, traces and session state can contain credentials or personal data. Context-wide headers go to all destinations in that context: never use this feature for secrets on pages with untrusted resources; scope authentication by trusted origin instead.

## How It Works

1. You describe what you want to test/automate
2. I auto-detect running dev servers (or ask for URL if testing external site)
3. I write custom Playwright code in `/tmp/playwright-test-*.js` (won't clutter your project)
4. I execute it via: `cd "$SKILL_DIR" && node run.js /tmp/playwright-test-*.js`
5. Results displayed in real-time, browser window visible for debugging
6. Remove your script, screenshots and any saved sessions after review; OS temporary-file cleanup is not a retention guarantee.

## Setup (First Time)

```bash
cd "$SKILL_DIR"
npm run setup
```

Requires Node 22 or later. Review package installation first: setup downloads dependencies and a browser, and can run package lifecycle code. Repeat browser installation when the installed Playwright version requires it. The executor does not silently install missing packages.

## Execution Pattern

**Step 1: Detect dev servers (for localhost testing)**

```bash
cd "$SKILL_DIR" && node -e "require('./lib/helpers').detectDevServers().then(s => console.log(JSON.stringify(s)))"
```

**Step 2: Write test script to /tmp with URL parameter**

```javascript
// /tmp/playwright-test-page.js
const { chromium } = require('playwright');

// Parameterized URL (detected or user-provided)
const TARGET_URL = 'http://localhost:3001'; // <-- Auto-detected or from user

(async () => {
  const browser = await chromium.launch({ headless: false });
  const page = await browser.newPage();

  await page.goto(TARGET_URL);
  console.log('Page loaded:', await page.title());

  await page.screenshot({ path: '/tmp/screenshot.png', fullPage: true });
  console.log('📸 Screenshot saved to /tmp/screenshot.png');

  await browser.close();
})();
```

**Step 3: Execute from skill directory**

```bash
cd "$SKILL_DIR" && node run.js /tmp/playwright-test-page.js
```

## Common Patterns

### Test a Page (Multiple Viewports)

```javascript
// /tmp/playwright-test-responsive.js
const { chromium } = require('playwright');

const TARGET_URL = 'http://localhost:3001'; // Auto-detected

(async () => {
  const browser = await chromium.launch({ headless: false, slowMo: 100 });
  const page = await browser.newPage();

  // Desktop test
  await page.setViewportSize({ width: 1920, height: 1080 });
  await page.goto(TARGET_URL);
  console.log('Desktop - Title:', await page.title());
  await page.screenshot({ path: '/tmp/desktop.png', fullPage: true });

  // Mobile test
  await page.setViewportSize({ width: 375, height: 667 });
  await page.screenshot({ path: '/tmp/mobile.png', fullPage: true });

  await browser.close();
})();
```

### Test Login Flow

```javascript
// /tmp/playwright-test-login.js
const { chromium } = require('playwright');

const TARGET_URL = 'http://localhost:3001'; // Auto-detected

(async () => {
  const browser = await chromium.launch({ headless: false });
  const page = await browser.newPage();

  await page.goto(`${TARGET_URL}/login`);

  await page.fill('input[name="email"]', '[email protected]');
  await page.fill('input[name="password"]', 'password123');
  await page.click('button[type="submit"]');

  // Wait for redirect
  await page.waitForURL('**/dashboard');
  console.log('✅ Login successful, redirected to dashboard');

  await browser.close();
})();
```

### Fill and Submit Form

```javascript
// /tmp/playwright-test-form.js
const { chromium } = require('playwright');

const TARGET_URL = 'http://localhost:3001'; // Auto-detected

(async () => {
  const browser = await chromium.launch({ headless: false, slowMo: 50 });
  const page = await browser.newPage();

  await page.goto(`${TARGET_URL}/contact`);

  await page.fill('input[name="name"]', 'John Doe');
  await page.fill('input[name="email"]', '[email protected]');
  await page.fill('textarea[name="message"]', 'Test message');
  await page.click('button[type="submit"]');

  // Verify submission
  await page.waitForSelector('.success-message');
  console.log('✅ Form submitted successfully');

  await browser.close();
})();
```

### Check for Broken Links

```javascript
const { chromium } = require('playwright');

(async () => {
  const browser = await chromium.launch({ headless: false });
  const page = await browser.newPage();

  await page.goto('http://localhost:3000');

  const links = await page.locator('a[href^="http"]').all();
  const results = { working: 0, broken: [] };

  for (const link of links) {
    const href = await link.getAttribute('href');
    try {
      const response = await page.request.head(href);
      if (response.ok()) {
        results.working++;
      } else {
        results.broken.push({ url: href, status: response.status() });
      }
    } catch (e) {
      results.broken.push({ url: href, error: e.message });
    }
  }

  console.log(`✅ Working links: ${results.working}`);
  console.log(`❌ Broken links:`, results.broken);

  await browser.close();
})();
```

### Take Screenshot with Error Handling

```javascript
const { chromium } = require('playwright');

(async () => {
  const browser = await chromium.launch({ headless: false });
  const page = await browser.newPage();

  try {
    await page.goto('http://localhost:3000', {
      waitUntil: 'domcontentloaded',
      timeout: 10000,
    });

    await page.screenshot({
      path: '/tmp/screenshot.png',
      fullPage: true,
    });

    console.log('📸 Screenshot saved to /tmp/screenshot.png');
  } catch (error) {
    console.error('❌ Error:', error.message);
  } finally {
    await browser.close();
  }
})();
```

### Test Responsive Design

```javascript
// /tmp/playwright-test-responsive-full.js
const { chromium } = require('playwright');

const TARGET_URL = 'http://localhost:3001'; // Auto-detected

(async () => {
  const browser = await chromium.launch({ headless: false });
  const page = await browser.newPage();

  const viewports = [
    { name: 'Desktop', width: 1920, height: 1080 },
    { name: 'Tablet', width: 768, height: 1024 },
    { name: 'Mobile', width: 375, height: 667 },
  ];

  for (const viewport of viewports) {
    console.log(
      `Testing ${viewport.name} (${viewport.width}x${viewport.height})`,
    );

    await page.setViewportSize({
      width: viewport.width,
      height: viewport.height,
    });

    await page.goto(TARGET_URL);
    await page.waitForTimeout(1000);

    await page.screenshot({
      path: `/tmp/${viewport.name.toLowerCase()}.png`,
      fullPage: true,
    });
  }

  console.log('✅ All viewports tested');
  await browser.close();
})();
```

## Inline Execution (Simple Tasks)

For quick one-off tasks, you can execute code inline without creating files:

```bash
# Take a quick screenshot
cd "$SKILL_DIR" && node run.js "
const browser = await chromium.launch({ headless: false });
const page = await browser.newPage();
await page.goto('http://localhost:3001');
await page.screenshot({ path: '/tmp/quick-screenshot.png', fullPage: true });
console.log('Screenshot saved');
await browser.close();
"
```

**When to use inline vs files:**

- **Inline**: Quick one-off tasks (screenshot, check if element exists, get page title)
- **Files**: Complex tests, responsive design checks, anything user might want to re-run

## Available Helpers

Optional utility functions in `lib/helpers.js`:

```javascript
const helpers = require('./lib/helpers');

// Detect running dev servers (CRITICAL - use this first!)
const servers = await helpers.detectDevServers();
console.log('Found servers:', servers);

// Safe click with retry
await helpers.safeClick(page, 'button.submit'); // one action; do not blindly retry submissions

// Safe type with clear
await helpers.safeType(page, '#username', 'testuser');

// Take timestamped screenshot
await helpers.takeScreenshot(page, 'test-result');

// Handle cookie banners
await helpers.handleCookieBanner(page, '[data-testid="cookie-reject"]'); // only if rejection was requested

// Extract table data
const data = await helpers.extractTableData(page, 'table.results');
```

See `lib/helpers.js` for full list.

## Custom HTTP Headers

Configure custom headers for all HTTP requests via environment variables. Useful for:

- Identifying automated traffic to your backend
- Getting LLM-optimized responses (e.g., plain text errors instead of styled HTML)
- Adding authentication tokens globally

### Configuration

**Single header (common case):**

```bash
cd "$SKILL_DIR" && PW_HEADER_NAME=X-Automated-By PW_HEADER_VALUE=playwright-skill \
  node run.js /tmp/my-script.js
```

**Multiple headers (JSON format):**

```bash
cd "$SKILL_DIR" && PW_EXTRA_HEADERS='{"X-Automated-By":"playwright-skill","X-Debug":"true"}' \
  node run.js /tmp/my-script.js
```

### Scope and data boundaries

The executor runs arbitrary Node code with the current account’s filesystem, environment and network privileges; it is not a sandbox. Review generated code and keep page content inert. Use test accounts and fixtures. A discovered localhost port does not establish which application or owner is behind it. Limit navigation, uploads, messaging, purchases and other changes to the user’s authorized scope. Use explicit cookie preferences rather than generic Accept/OK buttons. Screenshots, traces and session state can contain credentials or personal data. Context-wide headers go to all destinations in that context: never use this feature for secrets on pages with untrusted resources; scope authentication by trusted origin instead.

## How It Works

Headers are automatically applied when using `helpers.createContext()`:

```javascript
const context = await helpers.createContext(browser);
const page = await context.newPage();
// All requests from this page include your custom headers
```

For scripts using raw Playwright API, use the injected `getContextOptionsWithHeaders()`:

```javascript
const context = await browser.newContext(
  getContextOptionsWithHeaders({ viewport: { width: 1920, height: 1080 } }),
);
```

## Advanced Usage

For comprehensive Playwright API documentation, see [API_REFERENCE.md](API_REFERENCE.md):

- Selectors & Locators best practices
- Network interception & API mocking
- Authentication & session management
- Visual regression testing
- Mobile device emulation
- Performance testing
- Debugging techniques
- CI/CD integration

## Tips

- **CRITICAL: Detect servers FIRST** - Always run `detectDevServers()` before writing test code for localhost testing
- **Custom headers** - Use `PW_HEADER_NAME`/`PW_HEADER_VALUE` env vars to identify automated traffic to your backend
- **Use /tmp for test files** - Write to `/tmp/playwright-test-*.js`, never to skill directory or user's project
- **Parameterize URLs** - Put detected/provided URL in a `TARGET_URL` constant at the top of every script
- **DEFAULT: Visible browser** - Always use `headless: false` unless user explicitly asks for headless mode
- **Headless mode** - Only use `headless: true` when user specifically requests "headless" or "background" execution
- **Slow down:** Use `slowMo: 100` to make actions visible and easier to follow
- **Wait strategies:** Use `waitForURL`, `waitForSelector`, `waitForLoadState` instead of fixed timeouts
- **Error handling:** Always use try-catch for robust automation
- **Console output:** Use `console.log()` to track progress and show what's happening

## Troubleshooting

**Playwright not installed:**

```bash
cd "$SKILL_DIR" && npm run setup
```

**Module not found:**
Ensure running from skill directory via `run.js` wrapper

**Browser doesn't open:**
Check `headless: false` and ensure display available

**Element not found:**
Add wait: `await page.waitForSelector('.element', { timeout: 10000 })`

## Example Usage

```
User: "Test if the marketing page looks good"

Claude: I'll test the marketing page across multiple viewports. Let me first detect running servers...
[Runs: detectDevServers()]
[Output: Found server on port 3001]
I found your dev server running on http://localhost:3001

[Writes custom automation script to /tmp/playwright-test-marketing.js with URL parameterized]
[Runs: cd "$SKILL_DIR" && node run.js /tmp/playwright-test-marketing.js]
[Shows results with screenshots from /tmp/]
```

```
User: "Check if login redirects correctly"

Claude: I'll test the login flow. First, let me check for running servers...
[Runs: detectDevServers()]
[Output: Found servers on ports 3000 and 3001]
I found 2 dev servers. Which one should I test?
- http://localhost:3000
- http://localhost:3001

User: "Use 3001"

[Writes login automation to /tmp/playwright-test-login.js]
[Runs: cd "$SKILL_DIR" && node run.js /tmp/playwright-test-login.js]
[Reports: ✅ Login successful, redirected to /dashboard]
```

## Notes

- Each automation is custom-written for your specific request
- Automation is constrained by authorization, available browser support, site behavior and installed dependencies
- Auto-detects running dev servers to eliminate hardcoded URLs
- Use a private unique temporary directory and explicitly remove sensitive artifacts
- The executor copies CommonJS code into a private-mode unique file in the skill directory for dependency resolution; relative imports resolve there, not beside the input script. It removes only that invocation’s file on normal exit; crashes can leave it behind.
- Progressive disclosure - API_REFERENCE.md loaded only when advanced features needed

## When to Use
This skill is applicable to execute the workflow or actions described in the overview.

## Limitations
- The API reference mixes standalone `playwright` scripts with separate `@playwright/test` and `axe-playwright` projects; setup installs only the standalone library. Install test-runner dependencies in the intended test project before using runner examples.
- Link-check results are HTTP observations, not proof of broken links: HEAD may be unsupported or authorization-dependent. Keep checks to approved origins, cap count/time, and avoid authenticated cross-origin requests.
- For scripts containing `require()`, the wrapper does not inject `getContextOptionsWithHeaders`; import helpers explicitly. Always close browser/context in `finally` and propagate failures.
- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.