guide-swiftdata — Claude Code skill: SwiftData patterns
A skill for writing, reviewing and debugging SwiftData code: safe predicates, autosave rules and CloudKit constraints.
npx skills add Prisma-Labs-Dev/apple-skills --skill guide-swiftdata -a claude-codeWhat guide-swiftdata does
This is a pattern guide, not API reference. The agent reaches for it when you write models, chase a runtime crash in a predicate, or review code before a commit. Five reference files sit inside: references/core-rules.md covers autosave, relationships, delete rules, @Query restrictions, #Unique and @Transient; references/predicates.md lists supported predicates and the dangerous patterns that crash at runtime; references/cloudkit.md handles CloudKit constraints; references/indexing.md covers indexing on iOS 18+; references/class-inheritance.md covers model subclassing on iOS 26+.
The review order is fixed: core rules first, then predicates, then CloudKit if the project uses it, indexing for iOS 18+, inheritance for iOS 26+. On a partial task the agent loads only the file it needs, so context stays small. The skill targets Swift 6.2 and modern concurrency, will not push Core Data, and will not pull in third-party frameworks without asking.
One catch: with no SwiftData project, or a deployment target below iOS 18, some references never come into play because the version gates are baked into the review steps. Worth installing if you already write SwiftData and want the agent to flag real problems instead of nitpicking.
What it helps with
- check a predicate before it crashes the app at runtime
- work out autosave and delete rules for your models
- pick indexes for iOS 18+
- respect CloudKit constraints during sync
- spot mistakes in model subclassing for iOS 26+
Example prompts for the agent
- Review my SwiftData models against core-rules and predicates
- Check the predicates in this file — will any crash at runtime?
- We sync through CloudKit, check the constraints
How to install guide-swiftdata
1Skills CLI (Vercel)
npx skills add Prisma-Labs-Dev/apple-skills --skill guide-swiftdata -a claude-code2Manually: put the files in place
~/.claude/skills/guide-swiftdata/SKILL.mdCopy the whole skill folder; for one project use .claude/skills/guide-swiftdata/
1Skills CLI (Vercel)
npx skills add Prisma-Labs-Dev/apple-skills --skill guide-swiftdata -a codex2Manually: put the files in place
.agents/skills/guide-swiftdata/SKILL.mdFor all projects use ~/.agents/skills/
1Skills CLI (Vercel)
npx skills add Prisma-Labs-Dev/apple-skills --skill guide-swiftdata -a cursor2Manually: put the files in place
.cursor/skills/guide-swiftdata/SKILL.mdCursor also reads .agents/skills/ and .claude/skills/
1GitHub CLI
gh skill install Prisma-Labs-Dev/apple-skills guide-swiftdata2Manually: put the files in place
.github/skills/guide-swiftdata/SKILL.md1Skills CLI (Vercel)
npx skills add Prisma-Labs-Dev/apple-skills --skill guide-swiftdata -a gemini-cli2Platform CLI
gemini skills install https://github.com/Prisma-Labs-Dev/apple-skills --path skills/guide-swiftdataManually: put the files in place
.devin/skills/guide-swiftdata/SKILL.mdThe legacy .windsurf/skills/ path still works
Skills CLI (Vercel)
npx skills add Prisma-Labs-Dev/apple-skills --skill guide-swiftdata -a opencodeClaude.ai
Zip the folder and upload it in Settings → Capabilities → Skills
Step by step, with commands for each platform: How to install skills in Claude Code: five ways
Questions about guide-swiftdata
How do I install guide-swiftdata in Claude?
Run npx skills add Prisma-Labs-Dev/apple-skills --skill guide-swiftdata -a claude-code. The skill lands in ~/.claude/skills/guide-swiftdata/SKILL.md.
What does guide-swiftdata do?
It walks the agent through SwiftData patterns: autosave, relationships, predicates, CloudKit, indexing and class inheritance. It applies while you write, review or debug code.
Which versions does the skill need?
It targets Swift 6.2 and modern concurrency. Indexing references load for iOS 18+, class inheritance references for iOS 26+.
Source text
SKILL.md · MIT
--- name: guide-swiftdata description: SwiftData patterns — autosave, relationships, dangerous predicates, CloudKit constraints, indexing, class inheritance. Use when writing, reviewing, or debugging SwiftData code. type: guide origin: https://github.com/twostraws/SwiftData-Agent-Skill license: MIT --- > **Guide Skill** — This is an expert workflow/pattern guide, not API reference documentation. > Originally from [twostraws/SwiftData-Agent-Skill](https://github.com/twostraws/SwiftData-Agent-Skill) by Paul Hudson. MIT License. # SwiftData Patterns Write and review SwiftData code for correctness, modern API usage, and adherence to project conventions. Report only genuine problems — do not nitpick or invent issues. ## Core Instructions - Target Swift 6.2 or later, using modern Swift concurrency. - Prefer SwiftData across the board. Do not suggest Core Data unless the feature cannot be solved with SwiftData. - Do not introduce third-party frameworks without asking first. ## Review Process 1. Check for core SwiftData issues using `references/core-rules.md`. 2. Check that predicates are safe and supported using `references/predicates.md`. 3. If the project uses CloudKit, check for CloudKit-specific constraints using `references/cloudkit.md`. 4. If the project targets iOS 18+, check for indexing opportunities using `references/indexing.md`. 5. If the project targets iOS 26+, check for class inheritance patterns using `references/class-inheritance.md`. If doing partial work, load only the relevant reference files. ## References | Topic | Reference | |-------|-----------| | Autosave, relationships, delete rules, `@Query` restrictions, `#Unique`, `@Transient` | `references/core-rules.md` | | Supported predicates, dangerous patterns that crash at runtime, unsupported methods | `references/predicates.md` | | CloudKit constraints: no `#Unique`, optional requirements, eventual consistency | `references/cloudkit.md` | | Database indexing (iOS 18+), single and compound property indexes | `references/indexing.md` | | Model subclassing (iOS 26+), `@available` requirements, predicate filtering | `references/class-inheritance.md` |
© Prisma-Labs-Dev · MIT · Prisma-Labs-Dev/apple-skills
