simctl_shutdown_device · Simctl MCP: Risk & Policy

WHAT IT DOES

What simctl_shutdown_device does on Simctl

AI agents invoke simctl_shutdown_device to trigger actions in Simctl. 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 simctl_shutdown_device needs a policy

Shutting down a simulator device is an external operation that affects the state of a running process/device. It is not purely destructive (the device is not deleted, just stopped), but it executes a state-changing command. Misuse could interrupt active testing sessions or development workflows, giving it medium severity.

From the tool's definition 'Shutdown a simulator device' — triggers an external operation (shutting down a running iOS Simulator instance) via xcrun simctl commands

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

simctl_shutdown_device Rate-limited

simctl_shutdown_device 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": {
    "simctl_shutdown_device": {
      "limits": [
        {
          "counter": "simctl_shutdown_device_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 Simctl, so you can run agents against it safely.

FAQ

Questions about simctl_shutdown_device

What does the simctl_shutdown_device tool do? +

Shutdown a simulator device. It is categorised as a Execute tool in the Simctl MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on simctl_shutdown_device? +

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

What risk level is simctl_shutdown_device? +

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

Can I rate-limit simctl_shutdown_device? +

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

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

simctl_shutdown_device is provided by the Simctl MCP server (nzrsky/simctl-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.