MCP is the open standard that lets any AI agent connect to any tool or data source without custom API integrations — the USB-C port for AI. It solves the N×M problem: instead of building a bespoke connector for every model × every tool, you build the tool once as an MCP server and any compliant agent can discover and call it.
The three parts: MCP Host (the app, e.g. Claude Desktop), MCP Client (the connection inside the host), and MCP Server (the thing exposing tools/data). Created by Anthropic, donated to the Agentic AI Foundation (Dec 2025); the July 2026 spec revision made the transport stateless for enterprise-scale deployment.