What problem does it solve? SwiftData code often compiles cleanly yet crashes at runtime or silently loses data because Swift-language semantics are overridden by the Core Data machinery underneath, and Apple's own samples ship incomplete or non-compiling patterns. This Skill audits a macOS SwiftUI project to detect twelve specific SwiftData defects — from let on relationships to fatalError on ModelContainer — and fixes the one mechanical defect automatically. ## Core Features & Use Cases - Twelve-rule defect index (sd-01 to sd-12): Detects relationship mutability crashes, init-assignment data loss, missing initializers, the positional @Relationship(.cascade) type error, non-optional to-one traps, preview container crashes, off-actor mutation races, and missing save() calls. - Hybrid lint engine: Combines tier-1 grep tells with tier-2 ast-grep structural rules that express patterns grep cannot, emitting unified JSON and SARIF output with a CI gate on hard-fail findings. - Evidence-grounded verification: Cross-checks uncertain findings against a corpus of 1,857 real shipping macOS apps via the swiftui-ctx CLI and Apple documentation via Sosumi before reporting. - Use Case: Point the Skill at an in-progress macOS SwiftUI app using SwiftData; it locates candidates, reads each file in full, reports only 100%-certain findings to swiftui-audits/swiftdata/, and auto-fixes the @Relationship(.cascade) error under a fix-safety protocol. ## Quick Start Audit the SwiftData layer of my macOS SwiftUI project in the current directory and write findings to the swiftui-audits folder.
