What it looks like underneath

Underneath the SDK, MCP messages are structured data.

{
  "method": "tools/call",
  "params": {
    "name": "list_events",
    "arguments": { "date": "2030-05-14" }
  }
}

The method names the kind of request. The parameters name the tool and supply its inputs.

Most developers use an MCP software kit that creates these messages for them. The protocol still defines the shape both sides agree to understand.