set_sim_appearance · Sl Test MCP: Risk & Policy

WHAT IT DOES

What set_sim_appearance does on Sl Test

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

WHY IT NEEDS A POLICY

Why set_sim_appearance needs a policy

This tool modifies simulator settings (appearance mode) reversibly without deleting data, executing arbitrary code, or causing financial impact. It is a configuration change that can be easily undone by setting the appearance to a different value, making it a Write operation. Severity is low because misuse only affects the visual appearance of a development simulator environment with no blast radius beyond that.

From the tool's definition Tool name is 'set_sim_appearance' and description states it 'Sets the appearance mode (dark/light) of an iOS simulator.' The verb 'Sets' indicates modification of simulator configuration state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_sim_appearance Rate-limited

set_sim_appearance 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": {
    "set_sim_appearance": {
      "limits": [
        {
          "counter": "set_sim_appearance_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 Sl Test, so you can run agents against it safely.

FAQ

Questions about set_sim_appearance

What does the set_sim_appearance tool do? +

Sets the appearance mode (dark/light) of an iOS simulator. It is categorised as a Write tool in the Sl Test MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_sim_appearance? +

Register the Sl Test MCP server in PolicyLayer and add a rule for set_sim_appearance: 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 Sl Test. Nothing to install.

What risk level is set_sim_appearance? +

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

Can I rate-limit set_sim_appearance? +

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

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

set_sim_appearance is provided by the Sl Test MCP server (sampsonky/xcodebuildmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.