Compare two trace files to detect performance regressions or improvements
AI agents call compare_traces to retrieve information from XcodeTraceMCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and analyzes existing trace data to generate comparative insights. It performs no modifications to the traces, executes no external operations based on variable inputs, and has no destructive or financial implications. The output is purely informational analysis, making it a Read operation with minimal security risk.
From the tool's definition Tool name 'compare_traces' and description 'Compare two trace files to detect performance regressions or improvements' indicate data retrieval and analysis without modification.
Documented attack patterns abuse exactly the kind of access compare_traces gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and XcodeTraceMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for compare_traces:
{
"version": "1",
"default": "deny",
"tools": {
"compare_traces": {}
}
}compare_traces is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Compare two trace files to detect performance regressions or improvements. It is categorised as a Read tool in the XcodeTraceMCP MCP Server, which means it retrieves data without modifying state.
Register the XcodeTrace MCP server in PolicyLayer and add a rule for compare_traces: 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 XcodeTraceMCP. Nothing to install.
compare_traces is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the compare_traces 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 compare_traces. 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.
compare_traces is provided by the XcodeTrace MCP server (jamesrochabrun/xcodetracemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from XcodeTraceMCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
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