MCP Hono Stateless

🚀 Stateless Hono MCP Server

An MCP server example based on Hono, utilizing Streamable HTTP. It's developed from the official Express example simpleStatelessStreamableHttp.ts, and uses fetch-to-node for conversion. It can be deployed to Cloudflare Workers (and other Hono-supported environments).

The main differences compared to the Express example are as follows:

- import express, { Request, Response } from 'express';
+ import { Hono } from 'hono';
+ import { toFetchResponse, toReqRes } from 'fetch-to-node';

// ...

- const app = express();
- app.use(express.json());
+ const app = new Hono();

- app.post('/mcp', async (req: Request, res: Response) => {
+ app.post('/mcp', async (c) => {
+   const { req, res } = toReqRes(c.req.raw);

    const server = getServer();
    try {
      const transport: StreamableHTTPServerTransport = new StreamableHTTPServerTransport({
        sessionIdGenerator: undefined,
      });
      await server.connect(transport);
-     await transport.handleRequest(req, res, req.body);
+     await transport.handleRequest(req, res, await c.req.json());
      res.on('close', () => {
        console.log('Request closed');
        transport.close();
        server.close();
      });
+     return toFetchResponse(res);
    } catch (error) {

🚀 Quick Start

💻 Usage Examples

Basic Usage

To test with the example MCP client:

In the first terminal:

npm start

In the second terminal:

node node_modules/@modelcontextprotocol/sdk/dist/esm/examples/client/simpleStreamableHttp.js

This will attempt to connect to the MCP server running on port 3000. You can use connect <url>/mcp to connect to different hosts or ports.

Then you can run commands like list-prompts or list-tools to verify if your MCP server is working properly.

📦 Installation

To deploy the server:

npm run deploy

Here is an example session for the Hono MCP server deployed on Cloudflare Workers:

> connect https://mcp-hono-stateless.michael.workers.dev/mcp
Connecting to https://mcp-hono-stateless.michael.workers.dev/mcp...
Creating transport channel, session ID: undefined
Connected to the MCP server

> list-tools
Available tools:
  - start-notification-stream: Start sending periodic notifications to test the reconnection feature

> list-prompts
Available prompts:
  - greeting-template: A simple greeting prompt template

> call-tool start-notification-stream
Calling tool 'start-notification-stream' with parameters: {}

Notification #1: info - Periodic notification #1 at 2025-04-27 16:31:00
Notification #2: info - Periodic notification #2 at 2025-04-27 16:31:10
...
Tool result:
  Periodic notifications have been started every 100ms