MCP (Model Context Protocol)
An open standard for AI assistants to communicate with external tools, databases, APIs, and data sources through a unified JSON-RPC interface.
MCP (Model Context Protocol) was published by Anthropic in late 2024 and became the de-facto standard for AI tool integration in 2025. Think of it as USB-C for AI: instead of writing custom adapters for every tool, you implement MCP once and any compliant client (Claude Desktop, Claude Code, Cursor, Zed, ChatGPT) can use it.
The protocol defines three primitives a server can expose: tools (functions Claude can call, like 'send_slack_message'), resources (data Claude can read, like 'list of open Postgres tables'), and prompts (templates Claude can use as a starting point). Clients discover these capabilities at connect time and decide when to invoke them based on the user's request.
Adoption snapshot (April 2026): OpenAI, Google DeepMind, and most serious AI tooling speak MCP. The community ecosystem has grown from ~50 servers in January 2025 to over 1.990 today. ClaudeWave indexes the full directory.