@modelfetch/deno

Deno runtime adapter for building MCP (Model Context Protocol) servers with ModelFetch.

Installation

deno add npm:@modelfetch/deno

Quick Start

// server.ts
import { McpServer } from "npm:@modelcontextprotocol/sdk@^1.15.0/server/mcp.js";
import { z } from "npm:zod@^3.25.74";

const server = new McpServer({
  title: "My Deno MCP Server",
  name: "my-deno-server",
  version: "1.0.0",
});

server.registerTool(
  "roll_dice",
  {
    title: "Roll Dice",
    description: "Rolls an N-sided dice",
    inputSchema: { sides: z.number().int().min(2) },
  },
  ({ sides }) => ({
    content: [
      {
        type: "text",
        text: `🎲 You rolled a ${1 + Math.floor(Math.random() * sides)}!`,
      },
    ],
  }),
);

export default server;

// index.ts
import handle, { getEndpoint } from "npm:@modelfetch/deno";
import server from "./server.ts";

// Start the server
const httpServer = handle(server);
httpServer.finished.then(() => {
  console.log("Server stopped");
});

// Get the server address
const address = httpServer.addr;
if (address) {
  console.log(`Server running at: ${getEndpoint(address)}`);
}

API Reference

`handle(server, options?)`

Starts the MCP server with Deno-specific optimizations and returns a Deno.HttpServer instance.

server: The MCP server instance from @modelcontextprotocol/sdk
options: Optional Deno.ServeOptions for configuring the HTTP server

Returns: Deno.HttpServer

const httpServer = handle(server, {
  port: 3000,
  hostname: "localhost",
});

`getEndpoint(address)`

Gets the MCP server endpoint URL for connecting clients.

address: A Deno.Addr object from the HTTP server

Returns: string - The complete endpoint URL

const endpoint = getEndpoint(httpServer.addr); // "http://localhost:3000/mcp"

Running Your Server

# Development (with all permissions)
deno run -A index.ts

# Production (with specific permissions)
deno run --allow-net index.ts

# Compiled executable
deno compile -A index.ts -o mcp-server
./mcp-server

Permissions

Deno requires explicit permissions. For MCP servers, you typically need:

--allow-net: For the HTTP server
--allow-read: If reading files
--allow-write: If writing files
--allow-env: For environment variables
-A: Allow all (development only)

Configuration

Optional deno.json:

{
  "compilerOptions": {
    "strict": true
  },
  "imports": {
    "@modelfetch/deno": "npm:@modelfetch/deno",
    "@modelcontextprotocol/sdk": "npm:@modelcontextprotocol/sdk@^1.15.0",
    "zod": "npm:zod@^3.25.74"
  },
  "tasks": {
    "dev": "deno run -A index.ts",
    "build": "deno compile -A index.ts"
  }
}

Documentation

For complete documentation, examples, and guides, visit www.modelfetch.com/docs/runtimes/deno.

License

MIT