Swift Architecture Skill

Overview

Use this skill to pick the best Swift architecture playbook for SwiftUI/UIKit codebases and apply it to the user’s task.

Workflow

Step 1: Analyze the Request Context

Before selecting an architecture, capture:

• task type (new feature, refactor, PR review, debugging)
• UI stack (SwiftUI, UIKit, or mixed)
• scope (single screen, multi-screen, app-wide)
• existing conventions to preserve

Step 2: Select the Architecture

If the user explicitly names an architecture, treat it as the initial candidate and run a fit check before committing:

• validate against UI stack fit (SwiftUI/UIKit/mixed), state complexity, effect orchestration needs, team familiarity, and existing codebase conventions
• if it fits, proceed with the requested architecture
• if it mismatches key constraints, explicitly explain the mismatch and recommend the closest-fit alternative from references/selection-guide.md
• if the user still insists on a mismatched architecture, proceed with a risk-mitigated plan and state the risks up front

When no architecture is named, load references/selection-guide.md and infer the best fit from stated constraints (state complexity, team familiarity, testing goals, effect orchestration needs, and framework preferences). Explain the recommendation briefly.

Architecture reference mapping:

• MVVM → references/mvvm.md
• MVI → references/mvi.md
• TCA → references/tca.md
• Clean Architecture → references/clean-architecture.md
• VIPER → references/viper.md
• Reactive → references/reactive.md

Step 3: Analyze Existing Codebase (When Applicable)

When code already exists:

• detect current architecture and DI style
• note concurrency model (async/await, Combine, GCD, mixed)
• align recommendations to local conventions

Step 4: Produce Concrete Deliverables

Read the selected architecture reference and convert its guidance into deliverables tailored to the user's request:

• File and module structure: directory layout with file names specific to the feature
• State and dependency boundaries: concrete types, protocols, and injection points
• Async strategy: cancellation, actor isolation, and error paths
• Testing strategy: what to test, how to stub dependencies, and example test structure
• Migration path (for refactors): incremental steps to move from current to target architecture
• UI stack adaptation: where SwiftUI and UIKit guidance should differ for the chosen architecture

Step 5: Validate with Checklist

End with the architecture-specific PR review checklist from the reference file, adapted to the user's feature.

Output Requirements

• Keep recommendations scoped to the requested feature or review task.
• Prefer protocol-based dependency injection and explicit state modeling.
• Flag anti-patterns found in existing code and provide direct fixes.
• Include cancellation and error handling in all async flows.
• For explicit architecture requests, include a short fit result (fit or mismatch) with 1-2 reasons.
• For mismatch cases, include one closest-fit alternative and why it better matches the stated constraints.
• When writing code, include only the patterns relevant to the task — do not dump entire playbooks.
• Treat reference snippets as illustrative by default; add full compile scaffolding only if the user asks for runnable code.
• Ask only minimum blocking questions; otherwise proceed with explicit assumptions stated up front.
• When reviewing PRs, use the architecture-specific checklist and call out specific violations with line-level fixes.