core-data-diag

Core Data migration crashes often stem from schema mismatches between your data model and the persistent store. This Skill detects crash type, verifies store versus model versions, and applies safety-first migration patterns to preserve data during schema updates.

Thread-confinement errors occur when Core Data objects are accessed from threads other than the one that created them. This Skill analyzes threading violations, logs concurrent access patterns, and identifies which operations violate Core Data's thread-safety requirements.

N+1 query patterns happen when fetching relationships individually instead of prefetching them, multiplying database round trips. This Skill profiles your queries, detects prefetch opportunities, and recommends relationship batching to reduce database calls and improve performance.

Bridging SwiftData and Core Data requires careful model alignment and migration testing. This Skill diagnoses bridging conflicts, validates data integrity across both frameworks, and enforces patterns that prevent schema and concurrency mismatches when mixing them.

Safe migrations require verifying schema compatibility, testing with real production data, and checking for concurrency issues across devices. This Skill provides a diagnostic workflow covering crash detection, data preservation validation, and performance profiling on real devices and simulators.

Slowdowns stem from N+1 queries, inefficient fetch requests, or excessive thread switching. This Skill logs SQL activity, analyzes query patterns, and profiles concurrency behavior to identify and fix performance bottlenecks specific to your device environment.