Install an app on a simulator
AI agents use install_app to create or update resources in Simulator — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Simulator environment.
Installing an app writes new data (the app bundle) to the simulator. This is reversible (the app can be uninstalled), so it falls under Write rather than Destructive. Misuse could result in unauthorized or malicious apps being installed on the simulator, giving it a medium severity.
From the tool's definition 'Install an app on a simulator' — installs (creates/adds) an app onto a simulator environment
Documented attack patterns abuse exactly the kind of access install_app gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Simulator, and nothing reaches the server without passing your rules. This is the rule we recommend for install_app:
{
"version": "1",
"default": "deny",
"tools": {
"install_app": {
"limits": [
{
"counter": "install_app_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}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.
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Install an app on a simulator. It is categorised as a Write tool in the Simulator MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Simulator MCP server in PolicyLayer and add a rule for 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 Simulator. Nothing to install.
install_app is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the 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.
Set action: deny in the PolicyLayer policy for 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.
install_app is provided by the Simulator MCP server (joshuarileydev/simulator-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Simulator, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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5 Simulator tools catalogued and risk-classified — across an index of 43,000+ MCP servers.