iOS Launch Performance

Use this skill to review the path from an app launch request to first visible UI and early responsiveness.

Focus on work that happens:

• before main
• during UIKit or SwiftUI startup
• inside UIApplicationDelegate, UISceneDelegate, or SwiftUI App
• during root UI creation
• before the first visible frame
• before the first meaningful interaction
• during early post-launch work that still affects user-perceived readiness

This is not a general iOS performance skill. Use it only when the issue is launch-specific or when the code runs on the launch path.

Core Model

Treat launch as a pipeline with separate phases: