MCP (Model Context Protocol) server for se-cli — exposes all 62 Selenium browser automation tools for AI agents.
A thin wrapper that delegates to @browsers-cli/se-cli's MCP server.

se-mcp is the recommended way for MCP-aware AI clients (VS Code, Claude Desktop, Cursor, etc.) to use se-cli — a token-efficient Selenium browser automation CLI.

This package is a thin wrapper around se-cli's built-in MCP server. It provides a standalone entry point (npx @browsers-cli/se-mcp) so MCP clients can discover and invoke all browser automation tools without manually configuring the se-cli binary.

┌──────────────────┐     JSON-RPC 2.0      ┌──────────────────┐
│  MCP Client      │ ◄─── over stdio ───► │  se-mcp          │
│  (VS Code,       │                       │  (this package)  │
│   Claude, etc.)  │                       │  thin wrapper    │
└──────────────────┘                       └────────┬─────────┘
                                                    │
                                           require() │ delegates to
                                                    ▼
                                           ┌──────────────────┐
                                           │  @browsers-cli/  │
                                           │  se-cli          │
                                           │  MCP Server      │
                                           │  (mcp-server.ts) │
                                           └────────┬─────────┘
                                                    │
                                           JSON line │ over socket
                                                    ▼
                                           ┌──────────────────┐
                                           │  se-cli Daemon    │
                                           │  (long-lived)     │
                                           │  WebDriver +      │
                                           │  Selenium         │
                                           └────────┬─────────┘
                                                    │
                                                    ▼
                                           ┌──────────────────┐
                                           │  Browser         │
                                           │  (Chrome/Edge/   │
                                           │   Firefox)       │
                                           └──────────────────┘

The MCP server reads JSON-RPC 2.0 requests from stdin and writes responses to stdout. Browser commands are forwarded to the se-cli daemon over a Unix socket (or Windows named pipe), which holds the WebDriver instance across calls.

You do not need to install anything globally. MCP clients will use npx automatically:

npx @browsers-cli/se-mcp

npm install -g @browsers-cli/se-mcp

Note: se-mcp depends on @browsers-cli/se-cli as a peer dependency. It will be installed automatically by npx or when you install se-mcp with npm 7+.

Add to your VS Code settings (settings.json):

{
  "mcp.servers": {
    "se-cli": {
      "command": "npx",
      "args": ["-y", "@browsers-cli/se-mcp"]
    }
  }
}

Or use the bundled server.json file directly — copy its contents into your MCP client configuration.

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "se-cli": {
      "command": "npx",
      "args": ["-y", "@browsers-cli/se-mcp"]
    }
  }
}

Add to ~/.cursor/mcp.json:

{
  "mcpServers": {
    "se-cli": {
      "command": "npx",
      "args": ["-y", "@browsers-cli/se-mcp"]
    }
  }
}

Add to .mcp.json in your project root:

{
  "mcpServers": {
    "se-cli": {
      "command": "npx",
      "args": ["-y", "@browsers-cli/se-mcp"]
    }
  }
}

Use the server.json file included in this package:

{
  "mcpServers": {
    "se-cli": {
      "command": "npx",
      "args": ["-y", "@browsers-cli/se-mcp"],
      "env": {}
    }
  }
}

se-mcp exposes 62 MCP tools covering the full browser automation lifecycle. All tools are prefixed with browser_.

1. MCP client (e.g., VS Code) spawns npx @browsers-cli/se-mcp as a subprocess.
2. se-mcp loads the MCP server from @browsers-cli/se-cli and starts listening on stdin/stdout.
3. When the MCP client calls a tool (e.g., browser_open), the server maps it to se-cli CLI args and sends them to the se-cli daemon over a socket.
4. The daemon holds the WebDriver instance and executes the command, returning a JSON response.
5. The server wraps the response in a JSON-RPC 2.0 envelope and writes it to stdout.

The daemon architecture means the browser stays open across tool calls. There is no reconnection cost, no driver restart overhead, and the WebDriver instance is reused. This is what makes se-cli token-efficient compared to traditional MCP browser implementations.

The browser_snapshot tool returns a compact YAML-like accessibility tree with element references (e1, e2, etc.). Subsequent commands can reference these elements by ref instead of verbose CSS selectors, dramatically reducing token usage.

You can also use se-mcp programmatically:

const { startMcpServer, McpServer, toolDefinitions, mapToolToCliArgs } = require('@browsers-cli/se-mcp');

// Start the MCP server (reads JSON-RPC from stdin, writes to stdout)
startMcpServer();

// Or create an instance with a custom workspace directory
const server = new McpServer('/path/to/workspace');
server.start();

import { startMcpServer, McpServer, toolDefinitions, mapToolToCliArgs } from '@browsers-cli/se-mcp';

// startMcpServer(workspaceDir?: string): void
// McpServer: class { constructor(workspaceDir?: string); start(): void }
// toolDefinitions: ToolDef[]
// mapToolToCliArgs(toolName: string, args: any): string[] | null

• se-cli — The core Selenium CLI with daemon architecture
• se-cli documentation — Full documentation and guides
• se-cli npm — Core package on npm

Apache License 2.0 — see LICENSE for details.