set_rain_delay · Home Controller MCP: Risk & Policy

WHAT IT DOES

What set_rain_delay does on Home Controller

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

WHY IT NEEDS A POLICY

Why set_rain_delay needs a policy

This tool modifies the operational state of a smart home irrigation/schedule controller by pausing schedules for a set duration. It is reversible (delay can be cleared with 0, or expires naturally), so it falls under Write rather than Destructive. Misuse could disrupt irrigation or automation schedules, causing plants to go unwatered or home routines to be disrupted, giving it medium severity.

From the tool's definition Pause all schedules on the controller for the given duration... Use 0 to clear the delay

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_rain_delay Rate-limited

set_rain_delay 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_rain_delay": {
      "limits": [
        {
          "counter": "set_rain_delay_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 Home Controller, so you can run agents against it safely.

FAQ

Questions about set_rain_delay

What does the set_rain_delay tool do? +

Pause all schedules on the controller for the given duration (in seconds, max 604800 = 7 days). Use 0 to clear the delay. It is categorised as a Write tool in the Home Controller 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_rain_delay? +

Register the Home Controller MCP server in PolicyLayer and add a rule for set_rain_delay: 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 set_rain_delay? +

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

Can I rate-limit set_rain_delay? +

Yes. Add a rate_limit block to the set_rain_delay 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_rain_delay completely? +

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

set_rain_delay 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.