The short answer
The Model Context Protocol (MCP) is an open standard, published by Anthropic in late 2024, that lets AI assistants like Claude communicate with external tools, databases, APIs, and data sources using a common language.
If the AI is the brain, MCP is the USB-C port. Any tool that implements MCP can be plugged into Claude without writing custom integration code. That's why the ecosystem exploded from 50 servers in January 2025 to over 2,000 today.
Why it matters
Before MCP, if you wanted Claude to read your Notion, write SQL against Postgres, or control a browser, you had to either build a custom API wrapper yourself or wait for Anthropic to ship an official integration.
MCP flipped that. Now anyone can build a server that exposes tools, resources, or prompts over a standardized JSON-RPC interface. Claude discovers it automatically and can use it in conversations.
OpenAI adopted MCP in April 2025. Google DeepMind added support for Gemini. Cursor, Zed, Continue, Warp, and most serious AI devtools speak MCP today. It's become the de-facto standard.
How an MCP server works
An MCP server is a small program running on your machine (or in the cloud) that exposes one or more of three primitives: tools (functions Claude can call), resources (data Claude can read), and prompts (templates Claude can use).
When you launch Claude Desktop with an MCP server configured in claude_desktop_config.json, Claude connects over stdin/stdout or HTTP and asks 'what can you do?'. The server responds with a list of available tools and their schemas. Claude then decides when to call them based on what you ask.
Example: you install the GitHub MCP server, ask Claude 'what are my open PRs?', and Claude calls the server's list_pull_requests tool, gets back JSON, and summarizes it for you. Zero custom code.
Installing an MCP server
The simplest case is an npx-based server. Add this to your claude_desktop_config.json (~/Library/Application Support/Claude/claude_desktop_config.json on Mac, %APPDATA%/Claude/claude_desktop_config.json on Windows):
{"mcpServers":{"github":{"command":"npx","args":["-y","@modelcontextprotocol/server-github"],"env":{"GITHUB_PERSONAL_ACCESS_TOKEN":"ghp_..."}}}}Restart Claude Desktop. The server appears automatically. Same flow works for uvx (Python), pip+python, docker, and locally-built binaries.
We have 2000+ MCP servers indexed on ClaudeWave with ready-to-paste install snippets for each.
The top MCP servers right now
Browse the live leaderboard on our MCP category page. As of 2026-Q2, the most-used MCP servers cover: filesystem access, GitHub, Slack, Postgres/MySQL, web search (Brave, Tavily, Exa), browser automation (Playwright, Puppeteer), and LLM-vector stores (Pinecone, Chroma).