Model Context Protocol (MCP)
The Model Context Protocol (MCP) is an open standard that lets AI assistants connect to external tools and data sources through one consistent interface instead of a bespoke integration per pairing.
MCP standardises three things: how a tool describes itself, how it is called, and how results and errors are returned. An MCP server exposes capabilities; an MCP client — the assistant — reads the available tools and decides when to call them. Announced by Anthropic in late 2024, the protocol was handed to the Linux Foundation in late 2025.
Because tool descriptions are read by the model, they behave as part of the prompt: a vague description produces a tool called at the wrong moments. Anything an MCP server returns must be treated as untrusted data rather than as instructions the assistant may follow.
