Paul Hudson built this to catch the SwiftData mistakes that actually break things at runtime, not style nitpicks. It reviews your models and queries against a set of reference files covering core rules, predicate safety, CloudKit constraints, and iOS 18+ indexing. The output is organized by file with before/after fixes and a prioritized summary of what will cause crashes or data loss versus what's just suboptimal. Useful if you're working on a real SwiftData project and want to avoid the predicate gotchas and relationship bugs that only show up when users start deleting things. Targets Swift 6.2 and modern concurrency throughout.
npx skills add https://github.com/twostraws/swiftdata-agent-skill --skill swiftdata-pro