SOLID principles for Swift 6 and SwiftUI (iOS 26+). Files < 100 lines, protocols separated, @Observable, actors, Preview-driven development. Features Modular MANDATORY.
From fuse-swift-apple-expertnpx claudepluginhub fusengine/agents --plugin fuse-swift-apple-expertThis skill uses the workspace's default tool permissions.
references/anti-patterns.mdreferences/concurrency-patterns.mdreferences/dependency-inversion.mdreferences/interface-segregation.mdreferences/liskov-substitution.mdreferences/open-closed.mdreferences/single-responsibility.mdreferences/solid-principles.mdreferences/templates/model.mdreferences/templates/protocol.mdreferences/templates/service.mdreferences/templates/view.mdreferences/templates/viewmodel.mdGuides Payload CMS config (payload.config.ts), collections, fields, hooks, access control, APIs. Debugs validation errors, security, relationships, queries, transactions, hook behavior.
Designs, audits, and improves analytics tracking systems using Signal Quality Index for reliable, decision-ready data in marketing, product, and growth.
Enforces A/B test setup with gates for hypothesis locking, metrics definition, sample size calculation, assumptions checks, and execution readiness before implementation.
Before ANY implementation, use TeamCreate to spawn 3 agents:
Before writing ANY new code:
Core/Extensions/, Core/Utilities/, Core/Protocols/Core/ directly| Layer | Location | Max Lines |
|---|---|---|
| Views | Features/[Feature]/Views/ | 80 |
| ViewModels | Features/[Feature]/ViewModels/ | 100 |
| Services | Features/[Feature]/Services/ | 100 |
| Protocols | Features/[Feature]/Protocols/ | 30 |
| Shared | Core/{Models,Protocols,Services,Extensions,Utilities}/ | - |
NEVER use flat Sources/ structure - always Features/[Feature]/
| Rule | Value |
|---|---|
| File limit | 100 lines (split at 90) |
| ViewModels | @MainActor @Observable |
| Protocols | Features/[Feature]/Protocols/ or Core/Protocols/ ONLY |
| Models | Sendable structs |
| Documentation | /// on all public APIs |
| Previews | Every View MUST have #Preview |
| Topic | Reference | When to consult |
|---|---|---|
| SOLID Overview | solid-principles.md | Quick reference all principles |
| SRP | single-responsibility.md | Fat views/VMs, splitting files |
| OCP | open-closed.md | Adding providers, extensibility |
| LSP | liskov-substitution.md | Protocol contracts, testing |
| ISP | interface-segregation.md | Fat protocols, splitting |
| DIP | dependency-inversion.md | Injection, testing, mocking |
| Concurrency | concurrency-patterns.md | Actors, @MainActor, Sendable |
| Anti-Patterns | anti-patterns.md | Code smells detection |
| Template | When to use |
|---|---|
| view.md | SwiftUI View with subviews and #Preview |
| viewmodel.md | @Observable ViewModel with @MainActor |
| service.md | API Service, Mock, Cache actor |
| protocol.md | Service protocol, CQRS, Auth |
| model.md | Model, DTO, Error, Enum |
| Anti-Pattern | Fix |
|---|---|
| Files > 100 lines | Split at 90 |
| Protocols in impl files | Move to Protocols/ directory |
ObservableObject | Use @Observable |
| Completion handlers | Use async/await |
Missing #Preview | Add preview for every View |
| Non-Sendable in async | Use struct with let |
Flat Sources/ structure | Use Features/[Feature]/ |