boot_simulator · Xcode MCP: Risk & Policy

WHAT IT DOES

What boot_simulator does on Xcode

AI agents invoke boot_simulator to trigger actions in Xcode. 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 boot_simulator needs a policy

This tool starts/launches an iOS simulator, which is an external operation that triggers a system process. It doesn't merely read data, nor does it write/modify files, but it executes an action that starts a running simulator instance. Misuse could consume system resources or trigger unintended simulator environments, making it medium severity.

From the tool's definition Boot an iOS simulator by UDID or name

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

boot_simulator Rate-limited

boot_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": {
    "boot_simulator": {
      "limits": [
        {
          "counter": "boot_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 Xcode, so you can run agents against it safely.

FAQ

Questions about boot_simulator

What does the boot_simulator tool do? +

Boot an iOS simulator by UDID or name. It is categorised as a Execute tool in the Xcode MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on boot_simulator? +

Register the Xcode MCP server in PolicyLayer and add a rule for boot_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 Xcode. Nothing to install.

What risk level is boot_simulator? +

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

Can I rate-limit boot_simulator? +

Yes. Add a rate_limit block to the boot_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 boot_simulator completely? +

Set action: deny in the PolicyLayer policy for boot_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 boot_simulator? +

boot_simulator is provided by the Xcode MCP server (xcode-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

// THE FULL RECORD

boot_simulator is one line of Xcode's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →