open_simulator · Shotter MCP: Risk & Policy

WHAT IT DOES

What open_simulator does on Shotter

AI agents invoke open_simulator to trigger actions in Shotter. 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 open_simulator needs a policy

This tool launches an external application (iOS Simulator), which is an execution action that triggers an external operation. It's not merely reading data, and the effect depends on the system state. Misuse could interfere with running development workflows or consume system resources, warranting a medium severity.

From the tool's definition Open the iOS Simulator application. Use this if the simulator is not already running.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

open_simulator Rate-limited

open_simulator 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": {
    "open_simulator": {
      "limits": [
        {
          "counter": "open_simulator_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 Shotter, so you can run agents against it safely.

FAQ

Questions about open_simulator

What does the open_simulator tool do? +

Open the iOS Simulator application. Use this if the simulator is not already running. It is categorised as a Execute tool in the Shotter MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on open_simulator? +

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

What risk level is open_simulator? +

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

Can I rate-limit open_simulator? +

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

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

open_simulator is provided by the Shotter MCP server (nathanstitt/shotter). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.