An MCP server is a small program that connects an AI assistant to one outside tool: your database, your calendar, your help desk, a website you want checked. Once it is connected, you can ask the assistant about that tool and it fetches the real answer instead of guessing.
MCP stands for Model Context Protocol. Anthropic published it as an open standard in November 2024, and it is now supported by Claude, ChatGPT, Cursor, VS Code, Windsurf and many other assistants. Because it is a shared standard, a developer builds one server and it works in every assistant that speaks MCP.
- MCP servers listed here
- 5
- Categories they cover
- 4
- Free to use
- 5
How an MCP server works
Three parts are involved. The host is the app you talk to, such as Claude or Cursor. Inside it, an MCP client keeps a connection open to each server you have added. The MCP server offers a short list of actions and data, and does the actual work when the assistant calls one.
- Step 1You ask“When do the clocks change in London this year?” in Claude, Cursor or VS Code.
- Step 2The assistant picks a toolIt reads the tools each connected server offers and chooses the one that fits.
