Ios PersistenceSAFE

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The instruction file, verbatim from the audited commit — this is the text the model reads, and the surface the audit's instruction layer examines. Quoted here so you can judge it without cloning anything.

---
name: ios-persistence
description: Implement local persistence with SwiftData, Core Data, and secure storage. Use when setting up SwiftData models, Core Data stacks, or local persistence in iOS.
metadata:
  triggers:
    files:
    - '**/*.xcdatamodeld'
    - '**/*Model.swift'
    keywords:
    - PersistentContainer
    - FetchRequest
    - ManagedObject
    - Query
    - ModelContainer
    - Repository
---
# iOS Persistence

## **Priority: P0 (CRITICAL)**

## Implementation Workflow

1. **Choose storage tier** — SwiftData for iOS 17+, Core Data for legacy, Apple secure credential storage for secrets, UserDefaults for flags only.
2. **Define models** — Use `@Model` macro (SwiftData) or `.xcdatamodeld` (Core Data).
3. **Configure container** — Use `@MainActor` for `ModelContainer` (SwiftData) or `NSPersistentContainer` (Core Data).
4. **Perform background writes** — Use `newBackgroundContext()` (Core Data) to avoid UI lag; never heavy I/O on `viewContext`.
5. **Secure sensitive data** — Use secure storage for tokens and PII; never store in `UserDefaults`.

See [SwiftData and Core Data implementation examples](references/implementation.md)

## Anti-Patterns

- **No Heavy I/O on `viewContext`**: Use private background contexts
- **No String-based Predicates**: Use KeyPaths or generated helpers
- **No Missing Merge Strategy**: Set the merge policy (`mergePolicy`) explicitly (e.g., `mergeByPropertyObjectTrump`)

## References

- [SwiftData & Core Data Implementation](references/implementation.md)

SAFEgrade B · trust 89/100 Nothing in the source contradicts what it says it does. Grade A is reserved for packages that have also passed the behavioural sandbox.

What the source does

Filesystem

none-observed

Network

none-observed

Shell

none-observed

Dependencies

pinned

Secrets in source

none-found

Findings (0)

No findings outside the package's declared scope.

Gates applied: no_behavioural_pass.