Native App Performance (CLI-only)

SkillAI & models

Lets your agent profile a Mac app's performance from the command line and find the slowest code hotspots.

Then ask your AI: use the Native App Performance (CLI-only) skill

Details

Instructions available. Your AI can read the instructions. Execution depends on the setup they require.

Account requirements not reviewed. Check the skill instructions before use; Ahel provides instructions and does not run this skill.

No other account needed.

Add it as a step in a pipeline you build on Ahel, or connect Ahel to Claude, ChatGPT, Cursor, Claude Code or Codex and ask your AI to use it.

About this skill

Native app performance: xctrace, Time Profiler, traces, hotspots.

What this skill tells your AI

The instructions your AI receives, as published by steipete/agent-scripts in skills/native-app-performance/SKILL.md and read by Ahel’s review.

Goal: record Time Profiler via xctrace, extract samples, symbolicate, and propose hotspots without opening Instruments.

# Start app yourself, then attach
xcrun xctrace record --template 'Time Profiler' --time-limit 90s --output /tmp/App.trace --attach <pid>

xcrun xctrace record --template 'Time Profiler' --time-limit 90s --output /tmp/App.trace --launch -- /path/App.app/Contents/MacOS/App

scripts/extract_time_samples.py --trace /tmp/App.trace --output /tmp/time-sample.xml

# While app is running
vmmap <pid> | rg -m1 "__TEXT" -n

scripts/top_hotspots.py --samples /tmp/time-sample.xml \
  --binary /path/App.app/Contents/MacOS/App \
  --load-address 0x100000000 --top 30

Always confirm you’re profiling the correct binary (local build vs /Applications). Prefer direct binary path for --launch.
Ensure you trigger the slow path during capture (menu open/close, refresh, etc.).
If stacks are empty, capture longer or avoid idle sections.
xcrun xctrace help record and xcrun xctrace help export show correct flags.

ASLR means you must use the runtime __TEXT load address from vmmap.
If using a new build, update the --binary path; symbols must match the trace.
CLI-only flow: no need to open Instruments if stacks are symbolicated via atos.

Advanced