macos-app-performance

Measure one app, judge it against Apple's published thresholds, and report what to fix first. Everything here is macOS-applicable and sourced from Apple's documentation; where Apple's guidance is iOS-only, this skill says so instead of borrowing it, and where Apple's own material is archived or does not affirm macOS support, the reference covering it says so.

Step 1 — establish the subject

A running app is named by name, pid, or bundle path. Detect a project in the working directory, because it decides what can be measured:

find . -maxdepth 1 \( -name Package.swift -o -name '*.xcodeproj' -o -name '*.xcworkspace' \)   # Swift / Xcode (a bare glob aborts under zsh)
[ -f src-tauri/tauri.conf.json ] && echo tauri
[ -f package.json ] && grep -q '"electron"' package.json && echo electron

The app is usually not one process. Tauri, Electron, and anything with XPC helpers or a WebKit content process spread work across several, and the one doing the work is rarely the one named on the bundle. Enumerate with pgrep -fl <app-name> and attribute every number to a named process.

Measure a release build, with the accuracy settings Apple prescribes for performance work — see references/measurement.md. If only a debug build exists, say so in the report rather than presenting its numbers as the app's.

Step 2 — fix hangs first