Browser DevTools MCP for VS Code & Cursor

Playwright-powered browser automation and debugging for VS Code and Cursor via the Model Context Protocol (MCP).

This extension integrates browser-devtools-mcp into your IDE, enabling AI assistants like GitHub Copilot and Cursor AI to interact with real web browsers for testing, debugging, and automation tasks.

Features

• 🌐 Browser Automation - Navigate, click, fill forms, and interact with web pages

• 📸 Screenshots - Capture full-page or element screenshots

• ♿ Accessibility - Run accessibility audits and get ARIA/AX tree snapshots

• 📊 Web Vitals - Measure Core Web Vitals (LCP, INP, CLS, TTFB, FCP)

• 🔍 Network Inspection - Monitor HTTP requests and responses

• 🎭 Request Mocking - Stub and mock API responses

• ⚛️ React DevTools - Inspect React components and elements

• 🔭 OpenTelemetry - Distributed tracing integration with trace context propagation

• 🎨 Figma Comparison - Compare pages with Figma designs

• 🐛 Non-Blocking Debugging - Tracepoints, logpoints, exceptionpoints, watch expressions, probe snapshots

• ⚡ Execute - Batch multiple tool calls in one request via JavaScript and callTool(); on browser platform page (Playwright Page) is available for page.evaluate(), page.locator(), etc.

• 🌐 Playwright Browsers - On first install/upgrade, the extension downloads the browsers selected in settings (default: Chromium + headless shell + ffmpeg) into Playwright’s normal cache using playwright-core’s installer—no npx required. VSIX builds set PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 so binaries are not bundled. If that step fails for the Chromium stack, you may be prompted to use installed Google Chrome instead (Use system-installed browser). Run Browser DevTools MCP: Install Playwright Browsers... anytime to pick Chromium (default), Firefox, and/or WebKit: it updates install.chromium / install.firefox / install.webkit to match and downloads those engines.

• 📦 MCP Server - Shipped inside one universal VSIX (same artifact for all platforms). The package includes sharp + @img/sharp-wasm32; native sharp/libvips prebuild variants are excluded from VSIX contents. No npm required at runtime; the extension runs the bundled browser-devtools-mcp with node.

Related MCP server: Playwright MCP

Installation

From Open VSX Registry

1. Open VS Code or Cursor

2. Go to Extensions (Ctrl+Shift+X / Cmd+Shift+X)

3. Search for "Browser DevTools MCP"

4. Click Install

Or install via command line:

# VS Code
code --install-extension serkan-ozal.browser-devtools-mcp-vscode

# Cursor
cursor --install-extension serkan-ozal.browser-devtools-mcp-vscode

From VSIX

# VS Code
code --install-extension browser-devtools-mcp-vscode-x.x.x.vsix

# Cursor
cursor --install-extension browser-devtools-mcp-vscode-x.x.x.vsix

Registration: In Cursor the extension registers the MCP server via Cursor’s native MCP API (no mcp.json needed). In VS Code 1.96+ it uses vscode.lm.registerMcpServerDefinitionProvider. The server is started automatically when the extension is enabled.

Telemetry

The extension can send anonymous usage events (install/uninstall, browser install step, etc.) to help improve the product. The same opt-in/opt-out rules apply as for the bundled browser-devtools-mcp server. No PII is collected; only an anonymous ID in ~/.browser-devtools-mcp/config.json, plus event name and environment properties (e.g. extension version, OS, Node version).

• Events: cursor_ext_activated / cursor_ext_deactivated (extension lifecycle), cursor_ext_installed (only when first-install/upgrade path ran and bundled MCP path resolved), cursor_ext_install_failed, cursor_ext_browser_installed / cursor_ext_browser_install_failed, and cursor_ext_uninstalled (when the extension is uninstalled and deactivate runs with the extension listed in .obsolete). MCP registration state is included where relevant (mcp_server_registered / mcp_server_unregistered). If telemetry is disabled (setting, env, or config), no events are sent.

• Timing: Clients may batch or delay sending—events might not appear in analytics immediately. TELEMETRY_ENABLE=false and ~/.browser-devtools-mcp/config.json apply to both the extension and the bundled MCP process (the extension forwards the parent environment to the server).

How to disable telemetry

1. Setting (recommended): Set browserDevtoolsMcp.telemetry.enable to false in VS Code/Cursor settings. The extension syncs this to ~/.browser-devtools-mcp/config.json on activate and when the setting changes, so no telemetry events (including uninstall) are sent.

2. Environment variable: Set TELEMETRY_ENABLE=false before starting VS Code/Cursor.

3. Config file: Edit ~/.browser-devtools-mcp/config.json and set "telemetryEnabled": false.

MCP Server (bundled)

The browser-devtools-mcp package is a dependency of this extension and is included in the published VSIX with production node_modules. We publish a single universal VSIX where native sharp/libvips prebuild variants are excluded from the bundle and @img/sharp-wasm32 is included. @img/sharp-wasm32 is a direct extension dependency (aligned with the bundled sharp), and .npmrc sets force=true so npm installs it on normal hosts.

• Activate: The extension resolves node_modules/browser-devtools-mcp/dist/index.js inside the extension folder. No npm and no network required for the server binary itself.

• New server versions: Publish/build workflows are lockfile-driven (npm ci --omit=optional). Bump browser-devtools-mcp in package.json and refresh lockfile when you want to roll forward.

• Dependencies: browser-devtools-mcp and @img/sharp-wasm32 are regular dependencies in package.json for maintainers; end users do not run npm for MCP.

Maintainer: universal VSIX

• PR / CI: .github/workflows/build.yml — workflow_dispatch, pull_request (master), and push (main) triggers; on ubuntu-latest it runs npm ci --omit=optional, lint, build, and npx vsce package.

• Release / Open VSX: .github/workflows/publish-vscode-extension.yml — single release job runs npm ci --omit=optional, lint, build, version bump/tag/release, then publishes to Open VSX via HaaLeo/publish-vscode-extension@v2 (skipDuplicate: true) and uploads the produced VSIX as artifact.

• Packaging filter: .vscodeignore excludes @img/sharp-darwin-*, @img/sharp-win32-*, @img/sharp-linux-*, @img/sharp-libvips-* and keeps sharp + @img/sharp-wasm32. vsce collects production dependencies via npm list --production, so devDependencies are not bundled.

Local packaging check:

npm ci --omit=optional
npx vsce package

Playwright Browsers

The extension uses Playwright’s browser binaries (Chromium, Firefox, WebKit), stored in the default cache (e.g. ~/.cache/ms-playwright on Linux, ~/Library/Caches/ms-playwright on macOS).

• Which browsers to install: In Settings, use browserDevtoolsMcp.install.chromium, install.firefox, and install.webkit (default: Chromium group). On first install/upgrade, the extension calls Playwright’s installBrowsersForNpmInstall with that selection (unless Use system-installed browser is on or platform is Node). Playwright skips work when the chosen builds are already present in the cache (INSTALLATION_COMPLETE). Changing these settings triggers another install pass; restart the MCP session if it was already running. Install Playwright Browsers... in the Command Palette does the same selection UI and writes those three settings to match your choice, then runs the installer (so the sidebar/settings panel stay in sync).

• VSIX / CI: PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 is set when packaging so browser ZIPs are not part of the extension.

• Download failures (Chromium stack): If Playwright’s install step fails while the Chromium group is requested (network, proxy, firewall, Winldd on Windows, etc.), the extension shows one notification (error text in details) and may offer Use Google Chrome to enable Use system-installed browser (browserDevtoolsMcp.browser.useSystemBrowser). Google Chrome must be installed on the machine. Firefox/WebKit-only installs get a generic failure message instead. Restart the MCP session (or Restart Server) after accepting. You can also turn on Use system-installed browser manually in settings anytime.

To skip browser download (e.g. you use a system browser or custom path), set the environment variable PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 before starting VS Code/Cursor.

Configuration

Quick Settings

Open the Browser DevTools MCP panel in the Explorer sidebar to configure common settings.

Full Settings

Open VS Code Settings (Ctrl+, / Cmd+,) and search for "Browser DevTools MCP" or use the command:

Browser DevTools MCP: Open Settings

To (re)download Playwright binaries immediately:

Browser DevTools MCP: Install Playwright Browsers...

Available Settings

Settings below are passed to the MCP server as environment variables. Change them in Settings or in the Browser DevTools MCP sidebar panel (subset); restart the MCP session to apply.

General

Install (Playwright browsers to download on activate)

Browser

Node (when platform is node)

OpenTelemetry

AWS / Amazon Bedrock

Figma

Advanced (MCP)

Usage

Once installed, the MCP server is automatically available to AI assistants. Try prompts like:

Navigation & Screenshots:

Navigate to https://example.com and take a screenshot
Take a full-page screenshot of the current page
Wait for network to be idle and then take a screenshot

Accessibility Testing:

Check the accessibility of the current page
Get the ARIA snapshot for the navigation menu
Get the AX tree snapshot with occlusion checking enabled

Performance:

Get the Web Vitals for https://google.com
What is the LCP score of this page?
Measure Core Web Vitals and give me recommendations

Interaction:

Fill the login form with test@example.com and click submit
Click the "Sign Up" button and wait for the page to load
Scroll to the bottom of the page

Debugging:

Show me the console errors on this page
What network requests failed on this page?
Set a tracepoint at line 50 in main.js and capture the call stack
Get probe snapshots after triggering the code path

API Mocking:

Mock the /api/users endpoint to return an empty array
Intercept all API requests and add an auth header
List all active stubs and clear them

Execute (batch tool calls + optional page script):

Use execute to fill the login form and click submit in one call
Run a script that calls callTool('navigation_go-to', { url: '...' }) then callTool('a11y_take-aria-snapshot', {}, true)

Visualizer UI

Visualizer UI screenshot:

Visualizer UI renders MCP tool events as an animated scene. The UI connects to the Visualizer WebSocket stream at ws://localhost:<wsPort>.

How to open

1. Open the Browser DevTools MCP panel in VS Code/Cursor.

2. Set Show Visualizer to true.

3. Run Browser DevTools MCP: Restart Server.

4. Run any MCP tool (for example navigation_go-to, then content_take-screenshot).

If the panel does not open automatically, open Command Palette (Cmd+Shift+P) and run Browser DevTools MCP: Show Visualizer.

Alternative (run Visualizer UI locally for development):

From repo root:

cd visualizer-ui npm install npm run dev

Open http://localhost:3000 in your browser.

How it works (summary)

• The extension starts a Visualizer WebSocket server on browserDevtoolsMcp.visualizer.wsPort.

• The UI reads VIS_WS_PORT in visualizer-ui/src/main.ts and connects to ws://localhost:<wsPort>.

• Tool events (run_started, tool_started, tool_finished, run_done, etc.) are represented in the scene.

Settings you should configure

1. Show Visualizer: set to true to enable both the webview UI and the Visualizer WebSocket server.

2. browserDevtoolsMcp.visualizer.wsPort (default 3020): change this if the port is busy, then run Restart Server.

Available MCP Tools

Navigation Tools

Content Tools

Interaction Tools

Accessibility Tools

Observability Tools

Synchronization Tools

Stub Tools

React Tools

Execute

Figma Tools

Debug Tools (Non-Blocking)

When using Node platform (browserDevtoolsMcp.platform: node), additional tools: debug_connect, debug_disconnect, debug_get-logs.

Development

Prerequisites

• Node.js 22+

• VS Code 1.96+ or Cursor

Build

# Install dependencies
npm install

# Compile TypeScript
npm run compile

# Watch for changes
npm run watch

# Package extension
npm run package

Testing

1. Press F5 in VS Code/Cursor to launch Extension Development Host

2. The extension will be loaded in the new window

3. Open AI Chat (Copilot or Cursor AI) and test MCP tools

Troubleshooting

Restart the MCP server

If you run into problems—for example the MCP server fails to start, the browser that was opened has closed, MCP processes have leaked, or you see other odd behavior—try restarting the MCP server first:

1. Open the Command Palette (Ctrl+Shift+P / Cmd+Shift+P)

2. Run Browser DevTools MCP: Restart Server

This unregisters the server, stops any running MCP processes (e.g. Cursor-started ones), and registers it again so a fresh process is started.

MCP Server Not Starting

1. Reinstall the extension or install a fresh VSIX—the MCP server is bundled; a missing dist/index.js usually means a broken or partial install.

2. Check that Node.js 22+ is available to the IDE (extension host) and the extension is enabled.

3. Check Output panel for "Browser DevTools MCP" logs.

Browser Not Launching

1. Run Browser DevTools MCP: Install Playwright Browsers... and ensure Chromium (or your engine) is selected, or rely on install.* settings on first install/upgrade. If the Playwright download fails, enable Use system-installed browser in settings or choose Use Google Chrome when the extension prompts (Chromium stack only; Chrome must be installed). Skip download if you use a system browser only.

2. Try disabling headless mode in settings

3. Check if a custom executable path is needed (e.g. system browser or custom build)

Settings Not Applying

After changing settings, restart the MCP session:

1. Run the command Browser DevTools MCP: Restart Server

2. Or reload the VS Code/Cursor window (Cmd+Shift+P → "Developer: Reload Window")

Contributing

Contributions are welcome! Please open an issue or submit a pull request on GitHub.

License

MIT License - see LICENSE for details.

Links

• GitHub Repository - Extension source code

• Open VSX Registry - Extension page

• browser-devtools-mcp - Main MCP server (npm)

• VS Code MCP Documentation

• Model Context Protocol