This JavaScript Sandbox MCP Server provides a secure environment to execute JavaScript code with configurable constraints:
Run JavaScript in an isolated environment
Set memory limits (1MB to 100MB)
Configure execution timeouts (100ms to 30000ms)
Safely execute untrusted code such as plugins or bots
Provides a secure environment for executing JavaScript code with configurable memory and time limits, allowing safe evaluation of JavaScript snippets.
js-sandbox MCP Server
A Model Context Protocol server that provides a secure JavaScript execution environment.
Features
Tools
execute_js- Executes JavaScript code in an isolated environmentParameters:
code(required): JavaScript code to executetimeout(optional): Maximum execution time in milliseconds (100-30000ms)memory(optional): Memory limit in bytes (1MB-100MB)
Returns the result of code execution
Security
Isolated code execution in a controlled environment
Configurable execution time and memory limits
Protection against malicious code
Related MCP server: MCP-REPL
Development
Install dependencies:
Build the server:
Development mode with auto-rebuild:
Installation
To use with Claude Desktop, add the server configuration:
MacOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%/Claude/claude_desktop_config.json
Debugging
Since MCP servers communicate over stdio, debugging can be challenging. We recommend using MCP Inspector, which is available as:
The Inspector will provide a URL to access debugging tools in your browser.