trigger_automation · Home Assistant MCP Server MCP

WHAT IT DOES

What trigger_automation does on Home Assistant MCP Server

AI agents invoke trigger_automation to trigger actions in Home Assistant MCP Server. 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 trigger_automation needs a policy

This tool executes an automation, which runs a sequence of predefined actions in Home Assistant. The blast radius is high because automations can control physical devices (lights, locks, thermostats, cameras, etc.) or trigger complex workflows.

From the tool's definition Tool name 'trigger_automation' combined with description 'Manually trigger a Home Assistant automation' indicates execution of an automation workflow whose effects depend on what actions that automation contains.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

trigger_automation Rate-limited

trigger_automation 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": {
    "trigger_automation": {
      "limits": [
        {
          "counter": "trigger_automation_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 Assistant MCP Server, so you can run agents against it safely.

FAQ

Questions about trigger_automation

What does the trigger_automation tool do? +

Manually trigger a Home Assistant automation. It is categorised as a Execute tool in the Home Assistant MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on trigger_automation? +

Register the Home Assistant MCP Server MCP server in PolicyLayer and add a rule for trigger_automation: 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 Assistant MCP Server. Nothing to install.

What risk level is trigger_automation? +

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

Can I rate-limit trigger_automation? +

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

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

trigger_automation is provided by the Home Assistant MCP Server MCP server (mjrestivo16/mcp-homeassistant). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.