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name: performance description: Performance profiling and SwiftUI debugging skills — Instruments guidance, hangs, memory issues, slow launches, energy drain, unnecessary re-renders, and view identity problems. Use when an app is slow, janky, or resource-hungry. allowed-tools: [Read, Glob, Grep, Bash] last_verified: 2026-07-16 review_by: 2027-06-22

Performance Skills

Diagnose and fix performance problems, from system-level profiling to SwiftUI render behavior.

When This Skill Activates

Use this skill when the user:

• Reports the app is slow, janky, or hanging
• Wants to profile with Instruments (Time Profiler, Allocations, Hangs)
• Is investigating memory issues, slow launches, or energy drain
• Sees SwiftUI views re-rendering too often or slow body evaluations
• Asks about view identity problems or _printChanges()

Available Skills

Paths are relative to THIS file's directory — skills run with cwd set to the user's project, so resolve each path from this SKILL.md's own location.

Skill	Read	Covers
profiling	profiling/SKILL.md	Instruments workflows; hangs, memory, slow launch, energy diagnosis
swiftui-debugging	swiftui-debugging/SKILL.md	Unnecessary re-renders, view identity, slow body evaluations

How to Route

1. Match the request to a row above — system-level symptoms → profiling; SwiftUI render symptoms → swiftui-debugging.
2. Read that SKILL.md (relative to this file) plus any reference files it lists.
3. Apply the guidance to the user's code.