MCP (Model Context Protocol)

MCP, the Model Context Protocol, is an open standard for connecting AI applications to external systems — data, tools, prompts — implemented by Claude, ChatGPT, VS Code, Cursor and many others, so a server built once integrates everywhere. Adoption is its strongest argument, and it is now stewarded by the Agentic AI Foundation rather than by its author. The cost vendor material omits is real: most clients load every tool definition up front, so descriptions occupy the window before any work starts, and every intermediate result round-trips through the model. Install servers casually and you pay that tax on every single turn.