TypeScript MCP SDK: Complete Developer Guide

Overview

The TypeScript MCP SDK is the official library for building MCP servers in TypeScript. It supports tools, resources, prompts, transports, and the stdio and streamable-http transport.

Installation

npm install @modelcontextprotocol/sdk

Minimal Server Example

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";

const server = new McpServer({ name: "my-server", version: "1.0.0" });

server.tool(
  "add",
  { a: z.number(), b: z.number() },
  async ({ a, b }) => ({
    content: [{ type: "text", text: String(a + b) }],
  })
);

const transport = new StdioServerTransport();
await server.connect(transport);

Adding a Tool

Tools are the primary way MCP servers expose functionality to clients. Each tool has a name, input schema, and handler function.

server.tool("get_weather", { city: z.string() }, async ({ city }) => {
  const data = await fetchWeather(city);
  return { content: [{ type: "text", text: JSON.stringify(data) }] };
});

Supported Features

Testing Your Server

1. Start the server and verify it prints no startup errors.
2. Run npx @modelcontextprotocol/inspector and connect over stdio.
3. Call your tools and verify they return the expected responses.
4. Connect from Claude Desktop and confirm tool visibility.