trace_app · Xcode MCP: Risk & Policy

WHAT IT DOES

What trace_app does on Xcode

AI agents invoke trace_app 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 trace_app needs a policy

This tool executes xctrace, an external command-line tool, to instrument and trace a running application. It triggers external operations (launching/attaching to a process, collecting system-level performance data) whose effects depend on arguments such as the target app and trace template. This is clearly Execute-level, with high severity since it can attach to arbitrary processes and collect sensitive runtime data.

From the tool's definition Captures a performance trace of an application using xctrace

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

trace_app Rate-limited

trace_app 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": {
    "trace_app": {
      "limits": [
        {
          "counter": "trace_app_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 trace_app

What does the trace_app tool do? +

Captures a performance trace of an application using xctrace. 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 trace_app? +

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

What risk level is trace_app? +

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

Can I rate-limit trace_app? +

Yes. Add a rate_limit block to the trace_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 trace_app completely? +

Set action: deny in the PolicyLayer policy for trace_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 trace_app? +

trace_app 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

trace_app 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 →