Integrations

Allows execution of JavaScript code in a sandbox with support for one-time execution and stateful REPL sessions
Enables direct execution of JavaScript code in Node.js with support for asynchronous operations and module imports
Provides package management capabilities including installing, checking and listing npm packages for use in JavaScript execution

JavaScript MCP Server (js-mcp)

A Model Context Protocol (MCP) server that allows AI assistants to execute JavaScript code with stateful REPL sessions.

Features

Core Features

One-time JavaScript Execution: Execute JavaScript code directly in Node.js
Stateful REPL Sessions: Maintain variables and context across multiple executions
File System Operations: Read, write, and manipulate files
Package Management: Import modules and manage npm packages

Advanced Features

Secure sandboxed execution
Asynchronous code support
Error handling with formatted stack traces
Session management with automatic cleanup

Installation

# Clone the repository
git clone https://github.com/yourusername/js-mcp.git
cd js-mcp

# Install dependencies
npm install

# Build the project
npm run build

Usage

Run with stdio transport (for use with Claude Desktop)

npm start
# or
node dist/index.js --stdio

Run with HTTP transport

node dist/index.js --http
# Default port is 3000, or specify with PORT environment variable
PORT=3456 node dist/index.js --http

Available Tools

JavaScript Execution

execute_javascript: Run JavaScript code in a basic sandbox
execute_javascript_with_modules: Run JavaScript with module imports
execute_javascript_async: Run asynchronous JavaScript code

REPL Sessions

repl_create_session: Create a new REPL session
repl_execute: Execute code in a REPL session
repl_get_context: Get variable values in a session
repl_delete_session: Delete a session
repl_list_sessions: List all active sessions

File Operations

file_read: Read file contents
file_write: Write content to a file
file_list: List files in a directory
file_delete: Delete a file or directory
file_exists: Check if a file exists

Package Management

package_check: Check if a module is available
package_install: Install an npm package
package_list: List installed packages

Security

The server uses direct JavaScript execution with safety features:

Timeout limits for code execution
File system access limited to working directory
Path validation to prevent dangerous operations

Configuration

Configure the server by setting environment variables:

PORT: HTTP server port (default: 3000)
WORKING_DIRECTORY: Base directory for file operations (default: current directory)
SESSION_TIMEOUT: REPL session timeout in minutes (default: 30)

Development

# Start in development mode
npm run dev

# Run tests
npm test

# Lint code
npm run lint

# Format code
npm run format

License

MIT

This server cannot be installed

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security - not tested

F

license - not found

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quality - not tested

A server that enables AI assistants to execute JavaScript code with persistent context through stateful REPL sessions, file operations, and package management features.