Stateless Hono MCP Server
About
An example Hono MCP server using Streamable HTTP
Details
- Author
- mhart
- GitHub stars
- 102
- Downloads
- 287
- Categories
- Other
Jump to
- Streamable HTTP transport for MCP
- Deployable to Cloudflare Workers
- Start-notification-stream tool included
- Greeting-template prompt included
- Stateless server example
- Based on official MCP Express example
Setting up with Highlight
This MCP is not yet compatible with Highlight’s one-click setup. However, you can still use it with Highlight by following these steps:
- Download and install Highlight from highlightai.com/download
- Navigate to the plugins tab and select "Add Custom Plugin"
-
Configure the plugin with the settings below
Plugin Name
Stateless Hono MCP ServerCommand (node, npx, python, etc.)Please refer to the README for specific instructions on how to obtain API keys or other required environment variables.
- Enable "Start Automatically" if you want the plugin to start when Highlight launches
From the repository
Run npm start to start the server locally on port 3000, then connect using an MCP client like the one at node node_modules/@modelcontextprotocol/sdk/dist/esm/examples/client/simpleStreamableHttp.js with the command connect http://localhost:3000/mcp. Deploy to Cloudflare Workers using npm run deploy.
Claude Desktop / Cursor
Paste into your MCP client config file to install this server.
{
"mcpServers": {
"stateless hono mcp server": {
"mcp-hono-stateless": {
"command": "node",
"args": [
"node_modules/@modelcontextprotocol/sdk/dist/esm/examples/client/simpleStreamableHttp.js"
]
}
}
}
}McpServers
{
"mcp-hono-stateless": {
"command": "node",
"args": [
"node_modules/@modelcontextprotocol/sdk/dist/esm/examples/client/simpleStreamableHttp.js"
]
}
}Stateless Hono MCP Server
An example Hono MCP server using Streamable HTTP, based off the official Express example,
using fetch-to-node to convert, deployable to Cloudflare Workers (and anywhere else Hono runs).
The only real changes to the Express example are:
- 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:
npm start
In another:
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
npm run deploy
Here's an example session against a 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...
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
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