Deno

You can run Deno TypeScript or JavaScript code securely through a dedicated MCP server that lets you specify precise permissions and features. This setup enables you to execute Deno code within controlled boundaries, making it suitable for AI-assisted coding tasks and automated workflows.

How to use

After you configure the MCP server, you can ask your MCP client to execute Deno code with explicit permissions. You can run simple code without special permissions, or request network, file system, environment, or other permissions as needed. Commands are issued through your MCP client, which passes the request to the Deno MCP server for safe execution.

How to install

Prerequisites take care of the runtime and tooling you need to run the MCP server and its client integrations.

# Prerequisites
node --version  # Node.js 16 or higher
deno --version  # Deno installed
# Optional: Claude Desktop or Cline installed for client integration

Configuration and usage notes

Configure the Deno MCP server so your MCP client can reach and authorize it. The server is designed to be run locally and referenced by your client tools.

{
  "mcpServers": {
    "deno": {
      "command": "node",
      "args": [
        "/absolute/path/to/deno-mcp/dist/index.js"
      ],
      "disabled": false,
      "autoApprove": [
        "execute_deno_code",
        "check_deno_version"
      ]
    }
  }
}

Examples of usage

Basic usage runs a simple Deno program without extra permissions. You can request more permissions as needed.

// Example: just print Deno version and working directory
console.log("Hello from Deno MCP!");
console.log("Version:", Deno.version);
console.log("Current directory:", Deno.cwd());

With permissions and libraries

Grant network or file system permissions when your code needs them. You can combine permissions as required.

// Network example with file write
async function fetchData() {
  const response = await fetch("https://jsonplaceholder.typicode.com/todos/1");
  const data = await response.json();
  await Deno.writeTextFile("./todo.json", JSON.stringify(data, null, 2));
  console.log("Todo data saved to file");
}
fetchData();

Using Deno Standard Library

You can import modules from Deno's standard library and use them in your code with appropriate permissions.

import { serve } from "https://deno.land/std@0.192.0/http/server.ts";

const handler = (req) => new Response("Hello, Deno Server!");
serve(handler, { port: 8000 });

Troubleshooting

If you encounter issues, ensure Deno is installed and accessible, and verify that you have requested the necessary permissions for your code.

Common checks include ensuring proper permissions for network, read, write, env, and run operations, and watching for execution time limits.

Tools and capabilities

The MCP server exposes specific tools to perform actions like executing Deno code and querying the installed Deno version.

Available tools

execute_deno_code

Runs Deno TypeScript/JavaScript code with optional permission sets and unstable feature flags.

check_deno_version

Returns information about the installed Deno version.