kef_standby · Kef MCP: Risk & Policy

WHAT IT DOES

What kef_standby does on Kef

AI agents invoke kef_standby to trigger actions in Kef. 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 kef_standby needs a policy

This tool triggers an external operation on a physical device (KEF speakers), changing their power state to standby. It is not a simple data read or write, but an action that affects real-world hardware. It is reversible (speakers can be powered back on), so it doesn't qualify as Destructive. It fits best under Execute as it triggers an external operation on a networked device.

From the tool's definition Put the KEF speakers into standby (off)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

kef_standby Rate-limited

kef_standby 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": {
    "kef_standby": {
      "limits": [
        {
          "counter": "kef_standby_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 Kef, so you can run agents against it safely.

FAQ

Questions about kef_standby

What does the kef_standby tool do? +

Put the KEF speakers into standby (off). It is categorised as a Execute tool in the Kef MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on kef_standby? +

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

What risk level is kef_standby? +

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

Can I rate-limit kef_standby? +

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

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

kef_standby is provided by the Kef MCP server (nqrwhal/kef-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.