simctl_install_app · Simctl MCP: Risk & Policy

WHAT IT DOES

What simctl_install_app does on Simctl

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

WHY IT NEEDS A POLICY

Why simctl_install_app needs a policy

Installing an app writes/deploys new software to the simulator device. This is a reversible operation (apps can be uninstalled), so it falls under Write rather than Execute or Destructive. The blast radius is medium — misuse could install unwanted or malicious apps on a simulator, but it's limited to the simulator environment and not a production system.

From the tool's definition Install an app on a simulator device

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

simctl_install_app Rate-limited

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

FAQ

Questions about simctl_install_app

What does the simctl_install_app tool do? +

Install an app on a simulator device. It is categorised as a Write tool in the Simctl MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on simctl_install_app? +

Register the Simctl MCP server in PolicyLayer and add a rule for simctl_install_app: 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_install_app? +

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

Can I rate-limit simctl_install_app? +

Yes. Add a rate_limit block to the simctl_install_app 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_install_app completely? +

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

simctl_install_app 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.