Model Context Protocol (MCP) over MQTT 5 — reference implementation and draft protocol spec, with per-tool broker-enforced ACL.

{
  "mcpServers": {
    "cloudsignalmcp-over-mqtt": {
      "command": "npx",
      "args": [
        "-y",
        "@cloudsignal/mcp-over-mqtt"
      ]
    }
  }
}