MCP Servers Explained: Give Your AI Agent Real Tools
Versions used in this post — read this first: Python 3.12 · MCP Python SDK mcp 2.3.0 (specification revision 2026-07-28) · Transport: stdio · No API key, no account. Version note that matters: SDK v2 renamed the class most older tutorials use — code importing FastMCP was written for v1 and will not run on v2. This post uses MCPServer throughout. The direct answer MCP — the Model Context Protocol — is a standard way for an AI application to discover and call tools that live outside the model. Instead of every framework inventing its own plugin format, a tool is packaged once as an MCP server, and any MCP-aware host can list its tools, read their input schemas, and call them over a defined protocol. In the previous post, the tools lived inside the same file as the agent. That works for one program. MCP is for when a tool should outlive it — usable by a second agent, a different host, or next month's project. Host, client, server — in plain words Three roles appear in every ...