mcp-hono-stateless

# Stateless Hono MCP Server [](https://deploy.workers.cloudflare.com/?url=https://github.com/mhart/mcp-hono-stateless) An example [Hono](https://hono.dev/) MCP server using Streamable HTTP, based off [the official Express example](https://github.com/modelcontextprotocol/typescript-sdk/blob/4d6197ac07776ab95a2d63a781514a75740cf746/src/examples/server/simpleStatelessStreamableHttp.ts), using [fetch-to-node](https://github.com/mhart/fetch-to-node) to convert, deployable to [Cloudflare Workers](https://developers.cloudflare.com/workers/) (and anywhere else Hono runs). The only real changes to the Express example are: ```diff - 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) { ``` ## Testing with an example MCP client In one terminal: ```sh npm start ``` In another: ```sh node node_modules/@modelcontextprotocol/sdk/dist/esm/examples/client/simpleStreamableHttp.js ``` This will try to connect to the MCP server running on port 3000. You can use `connect <url>/mcp` to connect to a different host or port. Then you can run commands like `list-prompts` or `list-tools` to verify your MCP server is working. ## Deploying ```sh npm run deploy ``` Here's an example session against a Hono MCP server deployed on Cloudflare Workers: ```console > connect https://mcp-hono-stateless.michael.workers.dev/mcp Connecting to https://mcp-hono-stateless.michael.workers.dev/mcp... Transport created with session ID: undefined Connected to MCP server > list-tools Available tools: - start-notification-stream: Starts sending periodic notifications for testing resumability > list-prompts Available prompts: - greeting-template: A simple greeting prompt template > call-tool start-notification-stream Calling tool 'start-notification-stream' with args: {} Notification #1: info - Periodic notification #1 at 2025-04-22T16:20:50.178Z > Notification #2: info - Periodic notification #2 at 2025-04-22T16:20:50.278Z > Notification #3: info - Periodic notification #3 at 2025-04-22T16:20:50.378Z > Notification #4: info - Periodic notification #4 at 2025-04-22T16:20:50.478Z > Notification #5: info - Periodic notification #5 at 2025-04-22T16:20:50.578Z > Notification #6: info - Periodic notification #6 at 2025-04-22T16:20:50.678Z > Notification #7: info - Periodic notification #7 at 2025-04-22T16:20:50.778Z > Notification #8: info - Periodic notification #8 at 2025-04-22T16:20:50.878Z > Notification #9: info - Periodic notification #9 at 2025-04-22T16:20:50.978Z > Notification #10: info - Periodic notification #10 at 2025-04-22T16:20:51.078Z > Tool result: Started sending periodic notifications every 100ms ```