send_notification · Homeassistant MCP: Risk & Policy

WHAT IT DOES

What send_notification does on Homeassistant

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

WHY IT NEEDS A POLICY

Why send_notification needs a policy

Sending notifications creates new messages/alerts in a system, which is a reversible write operation. Severity is medium because unsolicited or spam notifications can degrade user experience and potentially be abused for social engineering or harassment, but the impact is not destructive or financial.

From the tool's definition Tool named 'send_notification' on a Home Assistant control server; no description provided. The name and context indicate this creates/sends notifications to users or devices.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_notification Rate-limited

send_notification 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": {
    "send_notification": {
      "limits": [
        {
          "counter": "send_notification_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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

FAQ

Questions about send_notification

What does the send_notification tool do? +

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

How do I enforce a policy on send_notification? +

Register the Homeassistant MCP server in PolicyLayer and add a rule for send_notification: 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 Homeassistant. Nothing to install.

What risk level is send_notification? +

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

Can I rate-limit send_notification? +

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

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

send_notification is provided by the Homeassistant MCP server (robbrad/homeassistant-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.