Use this skill when choosing, running, or interpreting iOS performance profiling workflows, including Instruments traces, signposts, XCTest metrics, MetricKit, Xcode Organizer, hangs, hitches, CPU, allocations, memory graphs, disk I/O, networking, power, or production performance signals. Do not use it as the deep domain skill for launch, SwiftUI, concurrency, perceived performance, or runtime issues unless the task is specifically about measurement, tool selection, trace interpretation, or verification.
