Hono Remote MCP Server

The Hono Remote MCP Server is a Boilerplate example that builds a Model Context Protocol (MCP) server using the Hono web framework, exposes four arithmetic tools, and deploys to Vercel as a serverless function.

What is the Hono Remote MCP Server?

The Hono Remote MCP Server is an example MCP server that turns simple math operations into remotely callable tools. It takes MCP client requests over HTTP and returns tool execution results, running on Hono and Vercel's serverless platform. The project is part of a curated collection of examples and solutions (the repository has 5,146 stars) and includes a live deployment at https://hono-mcp-demo.vercel.app/mcp.

Key Features

• Math operation tools — Exposes add, subtract, multiply, and divide tools that can be invoked by any MCP-compatible client.
• MCP protocol handling — Uses the mcp-handler library to process MCP protocol transport and tool dispatch automatically.
• TypeScript with Zod validation — The server is written in TypeScript and uses Zod schemas to validate tool inputs at runtime.
• Vercel serverless deployment — Optimized for serverless; deploy with vc deploy, build with vc build.
• Live demo — A hosted instance at https://hono-mcp-demo.vercel.app/mcp lets you test the server without setting it up.
• Local development workflow — Run vc dev to start a local server at http://localhost:3000 for testing changes.

Who is it for?

• Developers learning MCP: They can read the small codebase to see exactly how MCP tools are defined, validated, and served over HTTP.
• Teams creating MCP servers: They can clone the example and replace the four math tools with their own business tools, keeping the Hono and Vercel setup intact.
• Serverless API developers: They get a reference pattern for mounting a third-party handler into a Hono app and deploying to Vercel.

What can you do with it? (Use cases)

• AI app builders: Connect an MCP client (like Claude or other assistants) to the demo endpoint and immediately test arithmetic capabilities.
• Prototyping custom tools: Swap the math functions for database queries or third-party API calls to give LLMs real-world actions.
• Learning serverless TypeScript: Use the local workflow to inspect how Hono routes POST /mcp/* requests and how Zod guards tool arguments.

How does the Hono Remote MCP Server work?

1. Install dependencies with npm install.
2. Start locally with vc dev and visit http://localhost:3000.
3. Deploy with vc deploy to Vercel.
4. Point an MCP client to the /mcp endpoint; the server receives POST requests and executes the requested tool, returning the result to the client.

FAQ

What tools does this MCP server expose?

The server exposes four math tools: add, subtract, multiply, and divide. Each accepts two numeric arguments, and divide includes zero-division protection so it won't crash on division by zero.

What URL do MCP clients connect to?

MCP clients should connect to https://hono-mcp-demo.vercel.app/mcp, or to /mcp on your own deployment. The browser root (https://hono-mcp-demo.vercel.app) shows server information instead.

What stack is this built with?

Hono is the web framework, TypeScript provides static typing, Zod handles runtime validation, and the mcp-handler library manages the MCP protocol. The app targets Vercel's serverless functions.

Can I extend it with my own tools?

Yes, the example is designed as a starting point. Add new tool definitions and their Zod input schemas, and the mcp-handler will route calls to them automatically; then redeploy with vc deploy.