/ios-persistence

Implement local persistence with SwiftData, Core Data, and secure storage. Use when setting up SwiftData models, Core Data stacks, or local persistence in iOS.

hoangnguyen0403@hoangnguyen0403

GitHub

From plugin

agent-skills-standard

538200 skills1 MCP

Install

$ npx -y skills add hoangnguyen0403/agent-skills-standard --skill ios-persistence --agent claude-code

How it fires

How this skill gets triggered: by you, by Claude, or both.

Fires itselfAuto-invocation. Claude auto-loads it when your prompt matches the work.
You can call itInvoke it directly when you want it.
Slash command/ios-persistence

Context preview

The summary Claude sees to decide when to auto-load this skill.

Implement local persistence with SwiftData, Core Data, and secure storage. Use when setting up SwiftData models, Core Data stacks, or local persistence in iOS.

SKILL.md

ios-persistence.SKILL.md

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, Keychain or other secure 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`)