MCP TypeScript SDK

What is MCP TypeScript SDK?

The MCP TypeScript SDK is the official TypeScript implementation of the Model Context Protocol, the open protocol for plugging AI applications into the data sources and tools they need. You build a server that offers tools, resources and prompts, and any MCP host such as Claude Code, VS Code or Cursor can connect to it and let a model call them. Version 2, the current stable line, implements the 2026-07-28 spec and ships as separate packages including @modelcontextprotocol/server and @modelcontextprotocol/client, plus adapters for Express, Fastify, Hono and Node. Tool inputs are declared with a schema such as Zod, and the SDK validates each call before your handler runs. A full stdio server fits in one file, and client packages let you build applications that talk to MCP servers. The older v1 line, published as @modelcontextprotocol/sdk, gets bug fixes and security updates only. It is free open-source software installed from npm.

Use cases

• Build an MCP server in TypeScript
• Expose an internal API to AI assistants
• Write an MCP client application
• Add MCP to an Express or Hono app
• Run an MCP server on Cloudflare Workers
• Upgrade a project from SDK v1 to v2

Who it's for

• TypeScript developers
• JavaScript developers
• AI engineers
• Backend teams

Why use MCP TypeScript SDK

• A tool is a name, a schema and a handler, so you do not hand-write protocol messages.
• Zod-style input schemas validate every call before your code runs, which cuts defensive checks.
• Framework adapters let you add an MCP endpoint to the Express, Hono or Fastify app you already run.
• The same toolkit covers servers and clients, so one team can build both sides of an integration.
• A codemod package and migration guide reduce the work of moving from v1 to v2.

MCP TypeScript SDK features

• McpServer class with registerTool for defining tools
• Resources and prompts alongside tools
• Input validation against Zod schemas before handlers run
• stdio and Streamable HTTP serving
• Separate client package for talking to MCP servers
• Adapters for Express, Fastify, Hono and Node HTTP
• Runs on Node.js, Bun and Deno
• Sessions and authorization helpers
• Codemod package for migrating from v1
• Generated API reference for all packages

MCP TypeScript SDK integrations

• Claude Code
• VS Code
• Cursor
• GitHub Copilot
• Express
• Fastify
• Hono
• Zod

How to get started with MCP TypeScript SDK

1. Install @modelcontextprotocol/server with npm, and add the client or an adapter package if you need one.
2. Create an McpServer, then register tools with an input schema and an async handler.
3. Serve it over stdio with serveStdio, or over HTTP through the Express, Hono, Fastify or Node adapter.
4. Register the launch command in a host such as VS Code, Claude Code or Cursor.
5. Ask the assistant a question and approve the tool call it proposes.

MCP TypeScript SDK limitations

• v2 ships as separate packages and replaces the single v1 package, so existing projects must migrate
• v1 documents the 2025-11-25 spec and gets only fixes and security updates
• A stdio server must log to stderr because stdout carries the protocol
• It is a developer library, not a hosted service or end-user app

MCP TypeScript SDK pricing

MCP TypeScript SDK is open source, so you can use and self-host it for free.

Prices can change and may vary by country or exclude tax. Check the official pricing page.

MCP TypeScript SDK alternatives

The main MCP TypeScript SDK alternatives listed on Debuly are MCP Python SDK, FastMCP, Letta, LMQL, Agno and Bult. The table compares pricing and platforms; order is A–Z.

1. 

   Agno

   Python framework and AgentOS runtime for building agents, teams and workflows, then serving them as an API with a control plane.

   Developer platformsAutomation and agentsCoding
   Open sourceVisit Agno (official site)
2. 

   Bult

   Deployment platform for Node.js, Python and AI apps with Git deploys, one-click templates, an AI copilot and an MCP server for agents.

   Developer platformsAutomation and agentsCoding
   Free trialVisit Bult (official site)
3. 

   FastMCP

   Python framework for building Model Context Protocol servers, clients and interactive apps, with managed hosting via Prefect Horizon.

   Developer platformsCodingAutomation and agents
   Open sourceVisit FastMCP (official site)
4. 

   Letta

   Platform, formerly MemGPT, for building stateful AI agents with persistent memory, from a terminal app, SDK or API.

   Developer platformsAutomation and agentsCoding
   FreemiumVisit Letta (official site)
5. LM

   LMQL

   Programming language from ETH Zurich for LLM prompting that adds Python control flow, typed variables and hard output constraints.

   Developer platformsCodingAutomation and agents
   Open sourceVisit LMQL (official site)
6. 

   MCP Python SDK

   The official open-source Python library for writing Model Context Protocol servers and clients that give LLM apps access to tools and data.

   Developer platformsAutomation and agentsCoding
   Open sourceVisit MCP Python SDK (official site)

MCP TypeScript SDK FAQ

Sources & verification

Facts on this page come from the official sources below, each with the date we read it. Written by Debuly; the vendor did not review this page.

Image credits

• Logo: from ts.sdk.modelcontextprotocol.io · fetched 24 Oct 2026 · Vendor trademark, used only to identify the product; removed on request
• Cover: none collected yet, so a generated tile is shown.

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