A Model Context Protocol (MCP) server for taking screenshots and reading console logs from web pages using Playwright. This tool allows AI agents to automatically capture screenshots and monitor browser console output for debugging, testing, and development tasks.
NOTE: Almost all of the code in this repository has been auto-generated. That means you should probably not trust it too much. That being said, it does work and I'm using it myself.
NOTE: If the documentation is incorrect, please let me know or send a PR. If you too want to use a code generation tool to update the code for this project, PROJECT_CONTEXT.md
has been used as context to give a good overview of the various parts of the project. It might be a bit messy now but it's a good starting point and you're welcome to update it.
- 📸 High-quality screenshot capture using Playwright
- 📝 Console log monitoring and collection from web pages
- 🌐 Support for localhost and remote URLs
- 🍪 Cookie-based authentication for protected pages
- 🐳 Docker containerization for consistent environments
- ⚡ PNG, JPEG, and WebP format support with configurable quality
- 🛡️ Secure non-root container execution
- 🤖 Full MCP protocol integration with AI development tools
- 🔧 Configurable viewport sizes and capture options
- 📱 Full page and element-specific screenshot capture
⚠️ Browser warning and error capture (Permissions-Policy, security warnings)- ⚡ TypeScript with Biome for fast development
- 🧪 Comprehensive testing with Node.js built-in test runner
The easiest way to get started - no installation required!
# Install Chromium browser (one-time setup)
npx playwright install chromium
# Test that BrowserLoop works
npx browserloop@latest --version
That's it! The latest version of BrowserLoop will be downloaded and executed automatically. Perfect for MCP users who want zero-maintenance screenshots.
Add BrowserLoop to your MCP configuration file (e.g. ~/.cursor/mcp.json
):
{
"mcpServers": {
"browserloop": {
"command": "npx",
"args": ["-y", "browserloop@latest"],
"description": "Screenshot and console log capture server for web pages using Playwright"
}
}
}
💡 Using @latest
ensures you always get the newest features and bug fixes automatically.
Add BrowserLoop to Cursor with a single click using this deeplink:
🔗 Add BrowserLoop to Cursor
This deeplink will automatically configure BrowserLoop in your Cursor MCP settings with the optimal configuration using npx and the latest version.
Prerequisites: Make sure you have Chromium installed first:
npx playwright install chromium
🚨 Critical: BrowserLoop requires Chromium to be installed via Playwright before it can take screenshots.
Install Chromium browser:
npx playwright install chromium
Verify installation:
# Check Playwright installation
npx playwright --version
# Test BrowserLoop (if using NPX)
npx browserloop@latest --version
For containerized environments:
# Pull and run with Docker
docker run --rm --network host browserloop
# Or use docker-compose for development
git clone <repository-url>
cd browserloop
docker-compose -f docker/docker-compose.yml up
For contributors or advanced users who want to build from source:
# Clone the repository
git clone <repository-url>
cd browserloop
# Install dependencies
npm install
# Install Playwright browsers (required for screenshots)
npx playwright install chromium
# OR use the convenient script:
npm run install-browsers
# Build the project
npm run build
{
"mcpServers": {
"browserloop": {
"command": "node",
"args": [
"/absolute/path/to/browserloop/dist/src/index.js"
],
"description": "Screenshot and console log capture server for web pages using Playwright"
}
}
}
Replace /absolute/path/to/browserloop/
with your actual project path.
Once configured, you can use natural language commands in your AI tool:
Take a screenshot of https://example.com
Take a screenshot of https://example.com with width 1920 and height 1080
Take a screenshot of https://example.com in JPEG format with 95% quality
Take a full page screenshot of https://example.com
Take a screenshot of http://localhost:3000 to verify the UI changes
Read console logs from https://example.com
Check for console errors on https://example.com
Monitor console warnings from http://localhost:3000
Read only error and warning logs from https://example.com
Capture console output from https://example.com for debugging
BrowserLoop supports cookie-based authentication for capturing screenshots of login-protected pages during development:
Take a screenshot of http://localhost:3000/admin/dashboard using these cookies: [{"name":"connect.sid","value":"s:session-id.signature","domain":"localhost"}]
📖 For cookie extraction methods and development workflows, see:
Common development use cases:
- Local development servers with authentication
- Staging environment testing
- API documentation tools (Swagger, GraphQL Playground)
- Custom web applications during development
- Admin panels and protected routes
- 🔐 Cookie Authentication Guide - Complete guide for authenticated screenshots
- 📚 Complete API Reference - Detailed parameter documentation, examples, and response formats
Parameter | Type | Description | Default |
---|---|---|---|
url |
string | Target URL to capture (required) | - |
width |
number | Viewport width (200-4000) | 1280 |
height |
number | Viewport height (200-4000) | 720 |
format |
string | Image format (webp, png, jpeg) | webp |
quality |
number | Image quality (1-100) | 80 |
fullPage |
boolean | Capture full page | false |
selector |
string | CSS selector for element capture | - |
📖 See docs/API.md for complete parameter details, usage examples, and configuration options.
BrowserLoop can be configured using environment variables:
Variable | Default | Description |
---|---|---|
BROWSERLOOP_DEFAULT_WIDTH |
1280 |
Default viewport width (200-4000) |
BROWSERLOOP_DEFAULT_HEIGHT |
720 |
Default viewport height (200-4000) |
BROWSERLOOP_DEFAULT_FORMAT |
webp |
Default image format (webp , png , jpeg ) |
BROWSERLOOP_DEFAULT_QUALITY |
80 |
Default image quality (0-100) |
BROWSERLOOP_DEFAULT_TIMEOUT |
30000 |
Default timeout in milliseconds |
BROWSERLOOP_USER_AGENT |
- | Custom user agent string |
Variable | Default | Description |
---|---|---|
BROWSERLOOP_DEFAULT_COOKIES |
- | Default cookies as file path or JSON string (see Cookie Authentication Guide) |
Variable | Default | Description |
---|---|---|
BROWSERLOOP_CONSOLE_LOG_LEVELS |
log,info,warn,error,debug |
Comma-separated list of log levels to capture |
BROWSERLOOP_CONSOLE_TIMEOUT |
30000 |
Page navigation timeout in milliseconds (not log collection time) |
BROWSERLOOP_SANITIZE_LOGS |
true |
Enable/disable sensitive data sanitization in logs |
BROWSERLOOP_CONSOLE_WAIT_NETWORK_IDLE |
true |
Wait for network idle before finishing collection |
BROWSERLOOP_MAX_LOG_SIZE |
1048576 |
Maximum total log size in bytes (1MB) |
Note: Console log collection always waits exactly 3 seconds after page load to capture console messages. The timeout setting only affects how long the page has to initially load.
Console log sanitization is enabled by default (BROWSERLOOP_SANITIZE_LOGS=true
) to protect sensitive information. When enabled, the following patterns are automatically masked:
Pattern Type | Example Input | Masked Output |
---|---|---|
API Keys | sk_live_1234567890abcdef... |
[API_KEY_MASKED] |
Email Addresses | [email protected] |
[EMAIL_MASKED] |
JWT Tokens | eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9... |
[JWT_TOKEN_MASKED] |
Auth Headers | Bearer abc123token... |
[AUTH_HEADER_MASKED] |
URLs with Auth | https://api.com/data?token=secret123 |
[URL_WITH_AUTH_MASKED] |
Secret Variables | password: mySecretPass |
password: [VALUE_MASKED] |
To disable sanitization (for debugging):
BROWSERLOOP_SANITIZE_LOGS=false
Note: Sanitization preserves log structure while masking sensitive content, making logs safe for sharing and analysis.
Variable | Default | Description |
---|---|---|
BROWSERLOOP_RETRY_COUNT |
3 |
Number of retry attempts for failed operations |
BROWSERLOOP_RETRY_DELAY |
1000 |
Delay between retries in milliseconds |
Variable | Default | Description |
---|---|---|
BROWSERLOOP_DEBUG |
false |
Enable debug logging to /tmp/browserloop.log |
BROWSERLOOP_ENABLE_METRICS |
true |
Enable error metrics collection |
BROWSERLOOP_DISABLE_FILE_WATCHING |
false |
Disable automatic cookie file monitoring |
When BROWSERLOOP_DEBUG=true
, detailed logs are written to /tmp/browserloop.log
including:
- Cookie file loading and automatic refresh events
- File watching status and recreation events
- Screenshot operation details
- Configuration changes and errors
Monitor logs in real-time:
tail -f /tmp/browserloop.log
Note: Logs are written to a file (not console) to maintain compatibility with MCP's stdio protocol.
Create a cookies file:
// ~/.config/browserloop/cookies.json
[
{
"name": "connect.sid",
"value": "s:your-dev-session.signature",
"domain": "localhost"
}
]
Reference in MCP config:
{
"mcpServers": {
"browserloop": {
"command": "node",
"args": ["dist/src/mcp-server.js"],
"env": {
"BROWSERLOOP_DEFAULT_COOKIES": "/home/username/.config/browserloop/cookies.json",
"BROWSERLOOP_DEFAULT_FORMAT": "webp",
"BROWSERLOOP_DEFAULT_QUALITY": "85"
}
}
}
}
{
"mcpServers": {
"browserloop": {
"command": "node",
"args": ["dist/src/mcp-server.js"],
"env": {
"BROWSERLOOP_DEFAULT_COOKIES": "[{\"name\":\"session_id\",\"value\":\"your_session_value\",\"domain\":\"example.com\"},{\"name\":\"auth_token\",\"value\":\"your_auth_token\"}]",
"BROWSERLOOP_DEFAULT_FORMAT": "webp",
"BROWSERLOOP_DEFAULT_QUALITY": "85"
}
}
}
}
# Only capture warnings and errors
BROWSERLOOP_CONSOLE_LOG_LEVELS="warn,error"
# Debug mode with all logs, no sanitization
BROWSERLOOP_DEBUG="true"
BROWSERLOOP_SANITIZE_LOGS="false"
BROWSERLOOP_CONSOLE_LOG_LEVELS="log,info,warn,error,debug"
"Executable doesn't exist" Error
# Install Chromium browser (most common fix)
npx playwright install chromium
MCP Server Not Starting
- Test manually:
npx browserloop@latest --version
- Verify requirements:
- Node.js 20+:
node --version
- npm:
npm --version
- npx:
npx --version
- Node.js 20+:
- Check MCP config JSON syntax
Screenshots Show Login Pages
- Use cookie authentication (see Cookie Authentication Guide)
- Check cookie expiration and domain settings
Console Logs Are Empty
- Some production websites have no console output (this is normal)
- Test with development sites that have console activity
- Enable debug logging:
BROWSERLOOP_DEBUG=true
and check/tmp/browserloop.log
- Check log level filtering:
BROWSERLOOP_CONSOLE_LOG_LEVELS=log,info,warn,error,debug
Console Log Collection Timing
- Collection always waits exactly 3 seconds after page load
BROWSERLOOP_CONSOLE_TIMEOUT
controls page loading timeout, not log collection time- Fast sites will still take ~3-4 seconds total (load + 3s collection + processing)
Network/Connection Issues
- Test with external URLs first:
https://example.com
- For localhost: ensure your dev server is running
- Check firewall settings
Updating BrowserLoop
- NPX: Automatically uses latest version with
@latest
- no manual updates needed! - Check current version:
npx browserloop@latest --version
# Test complete setup
node --version && npm --version
npx playwright --version
# Test BrowserLoop
npx browserloop@latest --version
Enable debug logging:
Set BROWSERLOOP_DEBUG=true
in your MCP config and monitor /tmp/browserloop.log
📖 See docs/API.md#error-handling for detailed troubleshooting.
BrowserLoop is licensed under the GNU Affero General Public License v3.0 or later (AGPL-3.0-or-later).
- ✅ Free to use - Personal and commercial use allowed
- ✅ Free to modify - You can adapt the code to your needs
- ✅ Free to distribute - Share copies with others
- ✅ Patent protection - Contributors provide patent grants
⚠️ Copyleft - Derivative works must also be open source under AGPL-3.0⚠️ Network clause - If you run a modified version on a server, you must provide source code to users
Important: If you modify BrowserLoop and run it as a network service (e.g., web app, API server, or cloud service), the AGPL requires you to:
- Offer the complete source code to all users of your service
- Include a prominent notice about how users can access the source
- Use a compatible license for the entire service
- LICENSE - Full license text
Organizations can use BrowserLoop under the AGPL for commercial purposes, but must comply with the copyleft requirements. If you need to keep modifications private, consider:
- Using BrowserLoop without modifications
- Contributing improvements back to the community
- Contacting the maintainers about potential alternative licensing arrangements
For questions about licensing, please open an issue or contact the maintainers.