An MCP server is a lightweight process that Exposes a set of tools (functions the AI can call), resources (data the AI can read), and prompts (templates), Speaks the standardized MCP protocol over stdin/stdout or HTTP/SSE and acts as a bridge between the AI and a real service (your filesystem, a database, GitHub, Gmail, etc.)
Example: A filesystem MCP server exposes tools like read_file, write_file, list_directory — the AI calls these without knowing anything about the OS underneath. The fundamental shift is that tool makers now own and maintain integrations, not AI app developers. This decentralizes the ecosystem massively.
Client (AI app)
Protocol (The protocol is just JSON-RPC 2.0 under the hood.)
Server (tool)
0-2 years experience
5-8 years experience
8+ years experience
