MCP Server for Smart Home & IoT Orchestration

An MCP (Model Context Protocol) server that gives any MCP-compatible AI client (Claude, etc.) safe, structured access to control smart devices via Home Assistant and query local sensors over MQTT — turning natural-language instructions into validated device actions.

Architecture

AI client (Claude Desktop, etc.)
     │  MCP protocol (stdio/SSE)
     ▼
FastMCP server ──► Home Assistant REST/WebSocket API (device control)
     │
     └────────────► MQTT broker (sensor reads, local automation triggers)

Related MCP server: Home Assistant MCP Server

Tools exposed

• list_devices() — enumerate controllable entities from Home Assistant

• get_device_state(entity_id) — read current state

• set_device_state(entity_id, state, **attrs) — guarded: checks an allowlist before executing

• read_sensor(topic) — read latest value from an MQTT sensor topic

• run_automation(name) — trigger a pre-defined Home Assistant automation (never arbitrary scripts)

Tech stack

FastMCP (Python MCP server framework), Home Assistant REST/WebSocket API, MQTT (paho-mqtt).

Getting started

pip install -r requirements.txt
cp .env.example .env   # HA_URL, HA_TOKEN, MQTT_BROKER
python src/server.py

Then point your MCP client's config at this server (stdio transport by default — see docs/CLIENT_SETUP.md).

Safety design

• set_device_state checks ALLOWED_ENTITIES in config.py before sending any command — nothing outside an explicit allowlist can be controlled, by design, to prevent an LLM from accidentally (or via a malicious prompt) unlocking doors, disabling alarms, etc.

• run_automation only triggers automations pre-defined in Home Assistant, never arbitrary code.

• All tool calls are logged to logs/mcp_actions.log for auditability.

Status

Server scaffold, tool definitions, and the Home Assistant client wrapper are implemented. You must populate ALLOWED_ENTITIES for your own home before deploying — it ships empty (deny-by-default) on purpose.

License

MIT