Does this skill handle data validation during migration?

Yes, it generates logic to validate that data has been correctly mapped and saved to SwiftData before the original UserDefaults keys are archived.

Is the generated migration code thread-safe?

The skill generates asynchronous migration methods (async throws) designed to run efficiently without blocking the main thread during application startup.

What happens if a migration fails?

The logic includes safety checks and data preservation steps, ensuring that legacy data remains in UserDefaults until the new storage is successfully verified.

Can I use this for apps other than Leavn?

While optimized for specific patterns, the migration logic generated follows standard SwiftData best practices applicable to most iOS development projects.

SwiftData Migration Writer

Name: SwiftData Migration Writer
Author: willsigmon

bywillsigmon

•

Mobile Development

Generates robust migration logic for transitioning iOS application data from UserDefaults to SwiftData with built-in validation and rollback support.

The SwiftData Migration Writer is a specialized Claude Code skill designed to streamline the modernization of iOS app persistence layers. It automates the complex task of mapping legacy UserDefaults keys to new SwiftData entity fields, writing asynchronous migration methods that ensure data integrity. By implementing standard patterns for data preservation, archiving old keys, and marking migration status, this skill helps developers move away from unstructured storage toward robust, schema-driven databases without risking user data loss during app updates.

주요 기능

019 GitHub stars

02Automated PreferencesStore extension generation

03Built-in data preservation and rollback mechanisms

04Asynchronous migration method generation with error handling

05Validation logic to verify data integrity before archival

06Automated mapping of UserDefaults keys to SwiftData entity fields

사용 사례

01Modernizing legacy iOS application persistence layers to use SwiftData

02Refactoring app architecture while ensuring zero user data loss

03Migrating user preferences from key-value pairs to structured database entities

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add willsigmon/sigstack swiftdata-migration-writer

For use in Claude.ai and ChatGPT

주요 기능

019 GitHub stars

02Automated PreferencesStore extension generation

03Built-in data preservation and rollback mechanisms

04Asynchronous migration method generation with error handling

05Validation logic to verify data integrity before archival

06Automated mapping of UserDefaults keys to SwiftData entity fields

사용 사례

01Modernizing legacy iOS application persistence layers to use SwiftData

02Refactoring app architecture while ensuring zero user data loss

03Migrating user preferences from key-value pairs to structured database entities

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add willsigmon/sigstack swiftdata-migration-writer

For use in Claude.ai and ChatGPT