Performance Fast means two numbers: the first frame after a key press shows in under 100 ms, and nothing on the main thread blocks for more than 50 ms. Every change in this skill starts and ends with a measurement , so you know it helped. Symptom-by-symptom fixes are in recipes.md. For video, audio, camera, Metal, or large image pipelines, also read gpu-media.md. The loop 1. Reproduce. Write the exact steps, or add a probe command to the debug bridge ( skill) that runs the slow action and logs the time of each step. 2. Measure the release build. Debug Swift is 3 to 10 times slower and points…