Control climate devices (thermostats, AC) in Home Assistant. List devices, get state, set HVAC mode, temperature, or fan mode.
AI agents invoke climate_control to trigger actions in HomeAssistant MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool triggers real-world physical effects by controlling HVAC systems and thermostats — setting temperatures and modes. It goes beyond a simple write/update of data as it drives external hardware with tangible environmental impact. Misuse could result in unsafe temperatures (e.g., disabling heating in cold weather), making severity high.
From the tool's definition Control climate devices (thermostats, AC) ... set HVAC mode, temperature, or fan mode
Documented attack patterns abuse exactly the kind of access climate_control gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and HomeAssistant MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for climate_control:
{
"version": "1",
"default": "deny",
"tools": {
"climate_control": {
"limits": [
{
"counter": "climate_control_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
} climate_control stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Control climate devices (thermostats, AC) in Home Assistant. List devices, get state, set HVAC mode, temperature, or fan mode. It is categorised as a Execute tool in the HomeAssistant MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the HomeAssistant MCP server in PolicyLayer and add a rule for climate_control: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches HomeAssistant MCP. Nothing to install.
climate_control is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the climate_control rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for climate_control. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
climate_control is provided by the HomeAssistant MCP server (jango-blockchained/advanced-homeassistant-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from HomeAssistant MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
13 HomeAssistant MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.