---
title: Messages
icon: send
---

The MQTT MCP server leverages FastMCP 2.0's core building blocks - resource templates, tools, and prompts - to streamline MQTT receive and publish operations with minimal boilerplate and a clean, Pythonic interface.

### Receive Message

Each topic on a device is mapped to a resource (and exposed as a tool) and [resource templates](https://gofastmcp.com/servers/resources#resource-templates) are used to specify connection details (host, port) and receive parameters (topic, timeout).

```python
@mcp.resource("mqtt://{host}:{port}/{topic*}")
@mcp.tool(
    annotations={
        "title": "Receive Message",
        "readOnlyHint": True,
        "openWorldHint": True,
    }
)
async def receive_message(
    topic: str,
    host: str = settings.mqtt.host,
    port: int = settings.mqtt.port,
    timeout: int = 60,
) -> str:
    """Receives a message published to the specified topic, if any."""
    ...
```

### Publish Message

Publish operations are exposed as a [tool](https://gofastmcp.com/servers/tools), accepting the same connection details (host, port) and allowing to publish a message to a specific topic in a single, atomic call.

```python
@mcp.tool(
    annotations={
        "title": "Publish Message",
        "readOnlyHint": False,
        "openWorldHint": True,
    }
)
async def publish_message(
    topic: str,
    message: str,
    host: str = settings.mqtt.host,
    port: int = settings.mqtt.port,
) -> str:
    """Publishes a message to the specified topic."""
    ...
```
