How to Build a Claude Connector: MCP Server Tutorial (2025)
Step-by-step guide to building a Claude connector using MCP. Create custom tools that connect Claude to your APIs, databases, and services.

Want Claude to connect to your custom APIs, databases, or internal tools? You need to build an MCP server. MCP (Model Context Protocol) is the standard for extending Claude with new capabilities.
This tutorial walks you through building a working MCP server from scratch.
What you'll build:
- A working MCP server that Claude can use
- Custom tools that call external APIs
- Proper authentication handling
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What is MCP?
MCP (Model Context Protocol) is an open protocol that standardizes how AI assistants connect to external tools. Think of it as a USB-C port for LLMs—a universal connector.
How It Works
Claude connects to your MCP server using the protocol. When a user asks Claude something, Claude calls your tools, your server executes the action, and returns results.
Quick Start: Python MCP Server
Step 1: Set up your environment with uv and install the MCP SDK.
Step 2: Create a server.py file that initializes FastMCP and defines your tools.
Step 3: Configure Claude Desktop to connect to your server.
Connecting to Claude
Edit the Claude Desktop config file and add your MCP server details. Use absolute paths and restart Claude Desktop completely after making changes.
FAQ
How long does it take to build an MCP server?
A basic server with 2-3 tools can be built in an afternoon. Production-ready servers take longer.
Can I use any programming language?
Python and TypeScript have official SDKs. Other languages have community support.
Conclusion
Building an MCP server lets you extend Claude with custom capabilities. Start with the quick start examples, then build toward your specific use case.
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