update_automation · Home Assistant MCP Server MCP

WHAT IT DOES

What update_automation does on Home Assistant MCP Server

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

WHY IT NEEDS A POLICY

Why update_automation needs a policy

This tool creates or modifies data reversibly (Write category). While it doesn't delete automations (which would be Destructive), updating automation rules could alter critical home control logic, potentially affecting security or device behavior.

From the tool's definition Tool description states 'Update an existing Home Assistant automation'. The tool modifies automation configurations, which are data structures that control smart home behavior and device actions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_automation Rate-limited

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

FAQ

Questions about update_automation

What does the update_automation tool do? +

Update an existing Home Assistant automation. It is categorised as a Write tool in the Home Assistant 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 update_automation? +

Register the Home Assistant MCP Server MCP server in PolicyLayer and add a rule for update_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 update_automation? +

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

Can I rate-limit update_automation? +

Yes. Add a rate_limit block to the update_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 update_automation completely? +

Set action: deny in the PolicyLayer policy for update_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 update_automation? +

update_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.