set_dhw_mode · Plugwise MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_dhw_mode does on Plugwise MCP Server

AI agents use set_dhw_mode to create or update resources in Plugwise MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Plugwise MCP Server environment.

WHY IT NEEDS A POLICY

Why set_dhw_mode needs a policy

This tool creates or modifies smart home device configuration (DHW mode) reversibly. It does not delete data (Destructive), execute arbitrary code (Execute), involve money (Financial), or merely read data (Read). Setting a mode can be reversed by setting it to another mode.

From the tool's definition Tool name 'set_dhw_mode' indicates setting/modifying a mode parameter. DHW (Domestic Hot Water) mode is a configuration setting on smart home thermostats that controls hot water heating behavior. The action of 'set' implies modifying existing state reversibly.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_dhw_mode Rate-limited

set_dhw_mode stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_dhw_mode": {
      "limits": [
        {
          "counter": "set_dhw_mode_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about set_dhw_mode

What does the set_dhw_mode tool do? +

DHW mode:. It is categorised as a Write tool in the Plugwise MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_dhw_mode? +

Register the Plugwise MCP Server MCP server in PolicyLayer and add a rule for set_dhw_mode: 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 Plugwise MCP Server. Nothing to install.

What risk level is set_dhw_mode? +

set_dhw_mode is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit set_dhw_mode? +

Yes. Add a rate_limit block to the set_dhw_mode 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 set_dhw_mode completely? +

Set action: deny in the PolicyLayer policy for set_dhw_mode. 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 set_dhw_mode? +

set_dhw_mode is provided by the Plugwise MCP Server MCP server (tommertom/plugwise-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.