start_sauna · Home Controller MCP: Risk & Policy

WHAT IT DOES

What start_sauna does on Home Controller

AI agents invoke start_sauna to trigger actions in Home Controller. 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.

WHY IT NEEDS A POLICY

Why start_sauna needs a policy

This tool executes a command that causes external hardware (HUUM sauna) to perform an action. While starting a sauna is not inherently destructive or financial, it is an Execute action because it triggers a physical operation whose effects depend on the provided arguments (target temperature).

From the tool's definition Tool description states 'Start the sauna and set target temperature' — this actively triggers a physical device operation with parameters that control its behavior (temperature 40-110°C).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

start_sauna Rate-limited

start_sauna 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "start_sauna": {
      "limits": [
        {
          "counter": "start_sauna_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Home Controller, so you can run agents against it safely.

FAQ

Questions about start_sauna

What does the start_sauna tool do? +

Start the sauna and set target temperature (40-110°C). It is categorised as a Execute tool in the Home Controller MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on start_sauna? +

Register the Home Controller MCP server in PolicyLayer and add a rule for start_sauna: 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 Home Controller. Nothing to install.

What risk level is start_sauna? +

start_sauna is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit start_sauna? +

Yes. Add a rate_limit block to the start_sauna 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.

How do I block start_sauna completely? +

Set action: deny in the PolicyLayer policy for start_sauna. 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.

What MCP server provides start_sauna? +

start_sauna is provided by the Home Controller MCP server (winsthuang/home-controller). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.