Fast Playwright MCP

Fast Playwright MCP

This MCP server is a fork of the Microsoft one. https://github.com/microsoft/playwright-mcp

A Model Context Protocol (MCP) server that provides browser automation capabilities using Playwright. This server enables LLMs to interact with web pages through structured accessibility snapshots, bypassing the need for screenshots or visually-tuned models.

Key Features

• Fast and lightweight. Uses Playwright's accessibility tree, not pixel-based input.
• LLM-friendly. No vision models needed, operates purely on structured data.
• Deterministic tool application. Avoids ambiguity common with screenshot-based approaches.

Fast Server Features (This Fork)

• Token Optimization. All tools support an expectation parameter to control response content:
  • includeCode: false - Suppress Playwright code generation to reduce tokens
  • includeSnapshot: false - Skip page snapshot for minimal responses (70-80% token reduction)
  • includeConsole: false - Exclude console messages
  • includeTabs: false - Hide tab information
• Image Compression. Screenshot tool supports imageOptions:
  • format: 'jpeg' - Use JPEG instead of PNG
  • quality: 1-100 - Compress images (e.g., 50 for 50% quality)
  • maxWidth: number - Resize images to max width
• Batch Execution. Use browser_batch_execute for multiple operations:
  • Significant token reduction by eliminating redundant responses
  • Per-step and global expectation configuration
  • Error handling with continueOnError and stopOnFirstError options
• Snapshot Control. Limit snapshot size with snapshotOptions:
  • selector: string - Capture only specific page sections (recommended over maxLength)
  • format: "aria" - Accessibility tree format for LLM processing
• Diff Detection. Track only changes with diffOptions:
  • enabled: true - Show only what changed from previous state (massive token saver)
  • format: "minimal" - Ultra-compact diff output
  • Perfect for monitoring state changes during navigation or interactions
• Diagnostic System. Advanced debugging and element discovery tools:
  • browser_find_elements - Find elements using multiple search criteria (text, role, attributes)
  • browser_diagnose - Comprehensive page analysis with performance metrics and troubleshooting
  • Enhanced error handling with alternative element suggestions
  • Page structure analysis (iframes, modals, accessibility metrics)
  • Performance monitoring with execution time under 300ms
• Enhanced Selector System. Unified element selection with multiple strategies:
  • Selector Arrays: All element-based tools now support multiple selectors with automatic fallback
  • 4 Selector Types:
    • ref: System-generated element IDs from previous tool results (highest priority)
    • role: ARIA roles with optional text matching (e.g., {role: "button", text: "Submit"})
    • css: Standard CSS selectors (e.g., {css: "#submit-btn"})
    • text: Text content search with optional tag filtering (e.g., {text: "Click me", tag: "button"})
  • Intelligent Resolution: Parallel CSS resolution, sequential role matching, automatic fallback
  • Multiple Match Handling: When multiple elements match, returns candidate list for LLM selection
  • HTML Inspection: New browser_inspect_html tool for intelligent content extraction with depth control

Requirements

• Node.js 18 or newer
• VS Code, Cursor, Windsurf, Claude Desktop, Goose or any other MCP client

Getting started

First, install the Playwright MCP server with your client.

Standard config works in most of the tools:

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": [
        "@tontoko/fast-playwright-mcp@latest"
      ]
    }
  }
}

claude mcp add fast-playwright npx @tontoko/fast-playwright-mcp@latest

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "playwright": {
      "type": "local",
      "command": [
        "npx",
        "@tontoko/fast-playwright-mcp"
      ],
      "enabled": true
    }
  }
}

# For VS Code
code --add-mcp '{"name":"fast-playwright","command":"npx","args":["@tontoko/fast-playwright-mcp@latest"]}'

Configuration

Playwright MCP server supports following arguments. They can be provided in the JSON configuration above, as a part of the "args" list:

> npx @tontoko/fast-playwright-mcp@latest --help
  --allowed-origins <origins>  semicolon-separated list of origins to allow the
                               browser to request. Default is to allow all.
  --blocked-origins <origins>  semicolon-separated list of origins to block the
                               browser from requesting. Blocklist is evaluated
                               before allowlist. If used without the allowlist,
                               requests not matching the blocklist are still
                               allowed.
  --block-service-workers      block service workers
  --browser <browser>          browser or chrome channel to use, possible
                               values: chrome, firefox, webkit, msedge.
  --caps <caps>                comma-separated list of additional capabilities
                               to enable, possible values: vision, pdf.
  --cdp-endpoint <endpoint>    CDP endpoint to connect to.
  --config <path>              path to the configuration file.
  --device <device>            device to emulate, for example: "iPhone 15"
  --executable-path <path>     path to the browser executable.
  --headless                   run browser in headless mode, headed by default
  --host <host>                host to bind server to. Default is localhost. Use
                               0.0.0.0 to bind to all interfaces.
  --ignore-https-errors        ignore https errors
  --isolated                   keep the browser profile in memory, do not save
                               it to disk.
  --image-responses <mode>     whether to send image responses to the client.
                               Can be "allow" or "omit", Defaults to "allow".
  --no-sandbox                 disable the sandbox for all process types that
                               are normally sandboxed.
  --output-dir <path>          path to the directory for output files.
  --port <port>                port to listen on for SSE transport.
  --proxy-bypass <bypass>      comma-separated domains to bypass proxy, for
                               example ".com,chromium.org,.domain.com"
  --proxy-server <proxy>       specify proxy server, for example
                               "http://myproxy:3128" or "socks5://myproxy:8080"
  --save-session               Whether to save the Playwright MCP session into
                               the output directory.
  --save-trace                 Whether to save the Playwright Trace of the
                               session into the output directory.
  --storage-state <path>       path to the storage state file for isolated
                               sessions.
  --user-agent <ua string>     specify user agent string
  --user-data-dir <path>       path to the user data directory. If not
                               specified, a temporary directory will be created.
  --viewport-size <size>       specify browser viewport size in pixels, for
                               example "1280, 720"

User profile

You can run Playwright MCP with persistent profile like a regular browser (default), in isolated contexts for testing sessions, or connect to your existing browser using the browser extension.

Persistent profile

All the logged in information will be stored in the persistent profile, you can delete it between sessions if you'd like to clear the offline state. Persistent profile is located at the following locations and you can override it with the --user-data-dir argument.

# Windows
%USERPROFILE%\AppData\Local\ms-playwright\mcp-{channel}-profile

# macOS
- ~/Library/Caches/ms-playwright/mcp-{channel}-profile

# Linux
- ~/.cache/ms-playwright/mcp-{channel}-profile

Isolated

In the isolated mode, each session is started in the isolated profile. Every time you ask MCP to close the browser, the session is closed and all the storage state for this session is lost. You can provide initial storage state to the browser via the config's contextOptions or via the --storage-state argument. Learn more about the storage state here.

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": [
        "@tontoko/fast-playwright-mcp@latest",
        "--isolated",
        "--storage-state={path/to/storage.json}"
      ]
    }
  }
}

Browser Extension

The Playwright MCP Chrome Extension allows you to connect to existing browser tabs and leverage your logged-in sessions and browser state. See extension/README.md for installation and setup instructions.

Configuration file

The Playwright MCP server can be configured using a JSON configuration file. You can specify the configuration file using the --config command line option:

npx @tontoko/fast-playwright-mcp@latest --config path/to/config.json

{
  // Browser configuration
  browser?: {
    // Browser type to use (chromium, firefox, or webkit)
    browserName?: 'chromium' | 'firefox' | 'webkit';

    // Keep the browser profile in memory, do not save it to disk.
    isolated?: boolean;

    // Path to user data directory for browser profile persistence
    userDataDir?: string;

    // Browser launch options (see Playwright docs)
    // @see https://playwright.dev/docs/api/class-browsertype#browser-type-launch
    launchOptions?: {
      channel?: string;        // Browser channel (e.g. 'chrome')
      headless?: boolean;      // Run in headless mode
      executablePath?: string; // Path to browser executable
      // ... other Playwright launch options
    };

    // Browser context options
    // @see https://playwright.dev/docs/api/class-browser#browser-new-context
    contextOptions?: {
      viewport?: { width: number, height: number };
      // ... other Playwright context options
    };

    // CDP endpoint for connecting to existing browser
    cdpEndpoint?: string;

    // Remote Playwright server endpoint
    remoteEndpoint?: string;
  },

  // Server configuration
  server?: {
    port?: number;  // Port to listen on
    host?: string;  // Host to bind to (default: localhost)
  },

  // List of additional capabilities
  capabilities?: Array<
    'tabs' |    // Tab management
    'install' | // Browser installation
    'pdf' |     // PDF generation
    'vision' |  // Coordinate-based interactions
  >;

  // Directory for output files
  outputDir?: string;

  // Network configuration
  network?: {
    // List of origins to allow the browser to request. Default is to allow all. Origins matching both `allowedOrigins` and `blockedOrigins` will be blocked.
    allowedOrigins?: string[];

    // List of origins to block the browser to request. Origins matching both `allowedOrigins` and `blockedOrigins` will be blocked.
    blockedOrigins?: string[];
  };
 
  /**
   * Whether to send image responses to the client. Can be "allow" or "omit". 
   * Defaults to "allow".
   */
  imageResponses?: 'allow' | 'omit';
}

Standalone MCP server

When running headed browser on system w/o display or from worker processes of the IDEs, run the MCP server from environment with the DISPLAY and pass the --port flag to enable HTTP transport.

npx @tontoko/fast-playwright-mcp@latest --port 8931

And then in MCP client config, set the url to the HTTP endpoint:

{
  "mcpServers": {
    "playwright": {
      "url": "http://localhost:8931/mcp"
    }
  }
}

{
  "mcpServers": {
    "playwright": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "--init", "--pull=always", "mcr.microsoft.com/playwright/mcp"]
    }
  }
}

docker build -t mcr.microsoft.com/playwright/mcp .

import http from 'http';

import { createConnection } from '@tontoko/fast-playwright-mcp';
import { SSEServerTransport } from '@modelcontextprotocol/sdk/server/sse.js';

http.createServer(async (req, res) => {
  // ...

  // Creates a headless Playwright MCP server with SSE transport
  const connection = await createConnection({ browser: { launchOptions: { headless: true } } });
  const transport = new SSEServerTransport('/messages', res);
  await connection.sever.connect(transport);

  // ...
});

Tools

Token Optimization Features

Playwright MCP server includes advanced token optimization features to reduce token usage and improve performance through response filtering and batch execution.

Response Filtering with Expectation Parameter

All browser tools support an optional expectation parameter that controls what information is included in the response. This can significantly reduce token usage by excluding unnecessary data.

Basic Usage

// Standard call - includes all information (snapshot, console, tabs, etc.)
{
  "name": "browser_navigate",
  "arguments": {
    "url": "https://example.com"
  }
}

// Optimized call - only includes essential information
{
  "name": "browser_navigate",
  "arguments": {
    "url": "https://example.com",
    "expectation": {
      "includeSnapshot": false,
      "includeConsole": false,
      "includeTabs": false
    }
  }
}

Expectation Options

• includeSnapshot (boolean, default: varies by tool): Include page accessibility snapshot
• includeConsole (boolean, default: varies by tool): Include browser console messages
• includeDownloads (boolean, default: true): Include download information
• includeTabs (boolean, default: varies by tool): Include tab information
• includeCode (boolean, default: true): Include executed code in response

Advanced Snapshot Options

{
  "name": "browser_click",
  "arguments": {
    "element": "Login button",
    "ref": "#login-btn",
    "expectation": {
      "includeSnapshot": true,
      "snapshotOptions": {
        "selector": ".dashboard",
        "maxLength": 1000,
        "format": "text"
      }
    }
  }
}

Console Filtering Options

{
  "name": "browser_navigate",
  "arguments": {
    "url": "https://example.com",
    "expectation": {
      "includeConsole": true,
      "consoleOptions": {
        "levels": ["error", "warn"],
        "maxMessages": 5,
        "patterns": ["^Error:"],
        "removeDuplicates": true
      }
    }
  }
}

Batch Execution

Execute multiple browser actions in a single request with optimized response handling and flexible error control.

Basic Batch Execution

{
  "name": "browser_batch_execute",
  "arguments": {
    "steps": [
      {
        "tool": "browser_navigate",
        "arguments": { "url": "https://example.com/login" }
      },
      {
        "tool": "browser_type",
        "arguments": { 
          "element": "username field", 
          "ref": "#username", 
          "text": "testuser" 
        }
      },
      {
        "tool": "browser_type",
        "arguments": { 
          "element": "password field", 
          "ref": "#password", 
          "text": "password" 
        }
      },
      {
        "tool": "browser_click",
        "arguments": { "element": "login button", "ref": "#login-btn" }
      }
    ]
  }
}

Advanced Batch Configuration

{
  "name": "browser_batch_execute",
  "arguments": {
    "steps": [
      {
        "tool": "browser_navigate",
        "arguments": { "url": "https://example.com" },
        "expectation": { "includeSnapshot": false },
        "continueOnError": true
      },
      {
        "tool": "browser_click",
        "arguments": { "element": "button", "ref": "#submit" },
        "expectation": { 
          "includeSnapshot": true,
          "snapshotOptions": { "selector": ".result-area" }
        }
      }
    ],
    "stopOnFirstError": false,
    "globalExpectation": {
      "includeConsole": false,
      "includeTabs": false
    }
  }
}

Error Handling Options

• continueOnError (per step): Continue batch execution even if this step fails
• stopOnFirstError (global): Stop entire batch on first error
• Flexible combination allows for robust automation workflows

Tool-Specific Defaults

Each tool has optimized defaults based on typical usage patterns:

• Navigation tools (browser_navigate): Include full context for verification
• Interactive tools (browser_click, browser_type): Include snapshot but minimal logging
• Screenshot/snapshot tools: Exclude additional context
• Code evaluation: Include console output but minimal other info
• Wait operations: Minimal output for efficiency

Performance Benefits

• Token Reduction: 50-80% reduction in token usage with optimized expectations
• Faster Execution: 2-5x speed improvement with batch execution
• Reduced Latency: Fewer round trips between client and server
• Cost Optimization: Lower API costs due to reduced token consumption

Response Diff Detection

The Fast Server includes automatic diff detection to efficiently track changes between consecutive tool executions:

{
  "name": "browser_click",
  "arguments": {
    "element": "Load more button",
    "ref": "#load-more",
    "expectation": {
      "includeSnapshot": true,
      "diffOptions": {
        "enabled": true,
        "threshold": 0.1,
        "format": "unified",
        "maxDiffLines": 50,
        "context": 3
      }
    }
  }
}

Diff Detection Benefits

• Minimal token usage: Only changed content is shown instead of full snapshots
• Change tracking: Automatically detects what changed after actions
• Flexible formats: Choose between unified, split, or minimal diff formats
• Smart caching: Compares against previous response from the same tool

When to Use Diff Detection

1. UI interactions without navigation: Clicks, typing, hover effects
2. Dynamic content updates: Loading more items, real-time updates
3. Form interactions: Track changes as users fill forms
4. Selective monitoring: Use with CSS selectors to track specific areas

{
  "name": "browser_type",
  "arguments": {
    "element": "Search input",
    "ref": "#search",
    "text": "playwright",
    "expectation": {
      "includeSnapshot": true,
      "snapshotOptions": {
        "selector": "#search-results"
      },
      "diffOptions": {
        "enabled": true,
        "format": "minimal"
      }
    }
  }
}

Best Practices

1. Use batch execution for multi-step workflows
2. Enable diff detection for actions without page navigation
3. Disable snapshots for intermediate steps that don't need verification
4. Use selective snapshots with CSS selectors for large pages
5. Filter console messages to relevant levels only
6. Combine global and step-specific expectations for fine-grained control
7. Use minimal diff format for maximum token savings

Diagnostic System Examples

Find alternative elements when selectors fail:

{
  "name": "browser_find_elements",
  "arguments": {
    "searchCriteria": {
      "text": "Submit",
      "role": "button"
    },
    "maxResults": 5
  }
}

Generate comprehensive page diagnostics:

{
  "name": "browser_diagnose",
  "arguments": {
    "includePerformanceMetrics": true,
    "includeAccessibilityInfo": true,
    "includeTroubleshootingSuggestions": true
  }
}

Debug automation failures with enhanced errors: All tools automatically provide enhanced error messages with:

• Alternative element suggestions
• Page structure analysis
• Context-aware troubleshooting tips
• Performance insights

Network Request Filtering

The browser_network_requests tool provides advanced filtering capabilities to reduce token usage by up to 80-95% when working with network logs.

Basic Usage Examples

// Filter API requests only
{
  "name": "browser_network_requests",
  "arguments": {
    "urlPatterns": ["api/", "/graphql"]
  }
}

// Exclude analytics and tracking
{
  "name": "browser_network_requests", 
  "arguments": {
    "excludeUrlPatterns": ["analytics", "tracking", "ads"]
  }
}

// Success responses only
{
  "name": "browser_network_requests",
  "arguments": {
    "statusRanges": [{ "min": 200, "max": 299 }]
  }
}

// Recent errors only
{
  "name": "browser_network_requests",
  "arguments": {
    "statusRanges": [{ "min": 400, "max": 599 }],
    "maxRequests": 5,
    "newestFirst": true
  }
}

Advanced Filtering

// Complex filtering for API debugging
{
  "name": "browser_network_requests",
  "arguments": {
    "urlPatterns": ["/api/users", "/api/posts"],
    "excludeUrlPatterns": ["/api/health"],
    "methods": ["GET", "POST"],
    "statusRanges": [
      { "min": 200, "max": 299 },
      { "min": 400, "max": 499 }
    ],
    "maxRequests": 10,
    "newestFirst": true
  }
}

// Monitor only failed requests
{
  "name": "browser_network_requests", 
  "arguments": {
    "statusRanges": [
      { "min": 400, "max": 499 },
      { "min": 500, "max": 599 }
    ],
    "maxRequests": 3
  }
}

Regex Pattern Support

{
  "name": "browser_network_requests",
  "arguments": {
    "urlPatterns": ["^/api/v[0-9]+/users$"],
    "excludeUrlPatterns": ["\\.(css|js|png)$"]
  }
}

Token Optimization Benefits

• Massive reduction: 80-95% fewer tokens for large applications
• Focused debugging: See only relevant network activity
• Performance monitoring: Track specific endpoints or error patterns
• Cost savings: Lower API costs due to reduced token usage

When to Use Network Filtering

1. API debugging: Focus on specific endpoints and methods
2. Error monitoring: Track only failed requests
3. Performance analysis: Monitor slow or problematic endpoints
4. Large applications: Reduce overwhelming network logs
5. Token management: Stay within LLM context limits

Migration Guide

Existing code continues to work without changes. To optimize:

1. Start by adding expectation: { includeSnapshot: false } to intermediate steps
2. Use batch execution for sequences of 3+ operations
3. Gradually fine-tune expectations based on your specific needs
4. Use diagnostic tools when automation fails or needs debugging