Code Runner MCP

🚀 Let AI execute JavaScript/Python code with any package imports!

✨ Core Value

• 🔒 Secure Sandbox: Isolated execution environment protecting your host system
• 📦 Install-on-Demand: Dynamically import any npm/PyPI packages
• 🎯 Reduce Hallucinations: Let AI verify logic by executing code
• ⚡ Quick Validation: Test if packages meet your needs without local installation

🌐 Try it online: smithery.ai

🚀 Quick Start

Option 1: Using Deno (Recommended)

{
  "mcpServers": {
    "code-runner": {
      "command": "deno",
      "args": ["run", "--allow-all", "jsr:@mcpc/code-runner-mcp/bin"],
      "env": {
        "DENO_PERMISSION_ARGS": "--allow-net",
        "NODEFS_ROOT": "/tmp",
        "NODEFS_MOUNT_POINT": "/tmp"
      },
      "transportType": "stdio"
    }
  }
}

Option 2: Using Node.js

{
  "mcpServers": {
    "code-runner": {
      "command": "npx",
      "args": ["-y", "deno", "run", "--allow-all", "jsr:@mcpc/code-runner-mcp/bin"],
      "env": {
        "DENO_PERMISSION_ARGS": "--allow-net",
        "NODEFS_ROOT": "/tmp",
        "NODEFS_MOUNT_POINT": "/tmp"
      },
      "transportType": "stdio"
    }
  }
}

💡 Use Cases

JavaScript/TypeScript

// Import npm packages directly to test functionality
import { z } from "npm:zod";
import { serve } from "jsr:@std/http";

const schema = z.object({ name: z.string() });
console.log(schema.parse({ name: "test" }));

Python

# Dynamically install and use Python packages
import requests
response = requests.get("https://api.github.com")
print(f"Status code: {response.status_code}")

File System Access

# Access host file system (via NODEFS_ROOT and NODEFS_MOUNT_POINT)
import os
files = os.listdir('/tmp')  # List files at the mount point
print(f"Found {len(files)} files")

⚙️ Environment Variables

• DENO_PERMISSION_ARGS: JS/TS execution permissions (e.g., --allow-env --allow-net)
• NODEFS_ROOT: Host file system root directory path for Python access
• NODEFS_MOUNT_POINT: Mount point path in Python environment (defaults to NODEFS_ROOT if not specified)
• PYODIDE_PACKAGE_BASE_URL: Custom package download source for Pyodide (e.g., private mirror CDN)

🛡️ Security Features

• Deno Sandbox: Strict permission control with explicit authorization
• Pyodide WASM: WebAssembly isolated environment
• File System Isolation: Controlled host file access

📋 Technical Architecture

• JavaScript/TypeScript: Powered by Deno runtime
• Python: Powered by Pyodide WebAssembly technology
• Package Management: Dynamic installation from npm, JSR, and PyPI

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💬 Issues & Feedback: GitHub Issues
🌟 Repository: GitHub Repository