The MCP Guide: Building and Connecting Model Context Protocol Servers

A practical guide to extending AI assistants with your own tools, data, and workflows using the Model Context Protocol.

About This Book

The Model Context Protocol (MCP) is an open standard created by Anthropic that defines how AI models connect to external tools and data sources. Think of it as a universal adapter — like USB-C for AI — that lets any MCP-compatible application (Claude Desktop, Claude Code, Cursor, and many others) connect to any MCP server you build.

Before MCP, every AI integration was bespoke: a custom plugin for one app, a different API wrapper for another, brittle and non-portable. MCP changes that. You write a server once, and any compatible client can use it.

This book walks you through MCP from the ground up: what the protocol does, how to write your own server in Python, and how to connect it to the applications you already use.

Who This Book Is For

Developers who want to extend AI assistants with custom tools or internal APIs
Engineers building AI-powered workflows who need reliable, reusable integrations
Anyone curious about how tools like Claude Desktop or Cursor actually connect to external systems
Python developers comfortable with basic async programming

What You’ll Learn

The MCP architecture and how Hosts, Clients, and Servers relate to each other
How to write a fully functional MCP server using the Python SDK
How to define Tools (actions the AI can call), Resources (data it can read), and Prompts (reusable templates)
How to choose and implement the right transport (stdio vs HTTP/SSE)
How to connect your server to Claude Desktop, Claude Code, and Cursor
Advanced topics: OAuth authentication, sampling (servers calling back to the LLM), logging, and deployment

Book Structure

The book is organized in four parts:

Part 1 — Foundations (Chapters 0–1): What MCP is and how its architecture works.

Part 2 — Building a Server (Chapters 2–6): Step-by-step guide to writing MCP servers in Python, covering tools, resources, prompts, and transport options.

Part 3 — Connecting to Clients (Chapters 7–9): Practical configuration for Claude Desktop, Claude Code, Cursor, and building a custom client.

Part 4 — Going Further (Chapters 10–11): Authentication, advanced features, production patterns, and an action plan.

Author Notes

All code examples use Python 3.11+ and the mcp Python SDK (pip install mcp). Longer code examples live in the code/ subdirectory and are referenced from the text. Shorter snippets (≤20 lines) appear inline.

The MCP specification and SDK evolve quickly. This guide was written against the MCP spec as of early 2026. When in doubt, check the official MCP documentation.