Ask Claude Code to "add a screen that loads a user profile and shows their orders" and the output compiles. It also strong-captures self in three closures, blocks the main thread on a network call, mutates @State from a background actor, and leaks a coordinator. Nothing crashes in the simulator. Everything crashes in TestFlight.

Swift is hostile to AI defaults: ARC, the SwiftUI lifecycle, Combine, structured concurrency, and a decade of UIKit history coexist in the same target. Half the model's training data is Objective-C, half is pre-async/await Swift, and the rest is SwiftUI tutorials that ignore actor isolation. A CLAUDE.md next to Package.swift is the cheapest way to pull it back to current Apple practice.

Get the full CLAUDE.md Rules Pack — oliviacraftlat.gumroad.com/l/skdgt . The 13 rules below are a free preview.

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