/axiom-swift

name: axiom-swift
description: Use when the question is about Swift or its toolchain rather than a framework — modern idioms, noncopyable types, drag and drop, debug deep links, tvOS targets.
license: MIT

Swift Language & Platform

**You MUST use this skill for ANY Swift idiom review, ownership/noncopyable types, Transferable/drag-and-drop, debug deep links, or tvOS development.**

<!-- AXIOM_AUDITOR_INLINE_BEGIN — rewritten for Codex by scripts/build-codex.ts; do not hand-edit --> > **Auditors are skills here.** Where this router says "Launch `some-auditor` agent", invoke the > matching Codex skill instead — same procedure, no Claude Code agent required. > > Available: `axiom-swift-simplifier`. > > The ones that shell out — builds, tests, simulators, crash symbolication — need shell access to run. <!-- AXIOM_AUDITOR_INLINE_END -->

Quick Reference

| Symptom / Task | Reference | |----------------|-----------| | Outdated Swift patterns (Date(), CGFloat, DateFormatter) | See `skills/swift-modern.md` | | Foundation modernization (FormatStyle, URL.documentsDirectory) | See `skills/swift-modern.md` | | Common Claude hallucinations in Swift code | See `skills/swift-modern.md` | | Swift 6.4 idioms — `anyAppleOS`, `weak let`, `~Sendable` (`OS27`) | See `skills/swift-modern.md` | | Noncopyable types (~Copyable) | See `skills/ownership-conventions.md` | | borrowing/consuming parameter ownership | See `skills/ownership-conventions.md` | | InlineArray, Span, value generics; Swift 6.4 `borrow`/`mutate` accessors (`OS27`) | See `skills/ownership-conventions.md` | | Reducing ARC overhead | See `skills/ownership-conventions.md` | | Drag and drop (.draggable, .dropDestination) | See `skills/transferable-ref.md` | | Copy/paste (.copyable, PasteButton) | See `skills/transferable-ref.md` | | ShareLink, content sharing | See `skills/transferable-ref.md` | | Custom UTType declarations | See `skills/transferable-ref.md` | | TransferRepresentation choices | See `skills/transferable-ref.md` | | Debug-only deep links for simulator testing | See `skills/deep-link-debugging.md` | | Navigate to specific screens for screenshots | See `skills/deep-link-debugging.md` | | tvOS Focus Engine, Siri Remote input | See `skills/tvos.md` | | tvOS storage constraints (no guaranteed-persistent local storage) | See `skills/tvos.md` | | tvOS text input, AVPlayer tuning | See `skills/tvos.md` | | TVUIKit components | See `skills/tvos.md` | | Simplify Swift for clarity (behavior-preserving cleanups) | `swift-simplifier` agent — `axiom-swift-simplifier` |

Decision Tree

digraph swift {
    start [label="Swift task" shape=ellipse];
    what [label="What do you need?" shape=diamond];

    start -> what;
    what -> "skills/swift-modern.md" [label="modern idioms,\noutdated patterns,\nFoundation APIs"];
    what -> "skills/ownership-conventions.md" [label="~Copyable, borrowing,\nconsuming, InlineArray,\nSpan, ARC reduction"];
    what -> "skills/transferable-ref.md" [label="drag & drop, copy/paste,\nShareLink, UTTypes,\nTransferable conformance"];
    what -> "skills/deep-link-debugging.md" [label="debug deep links,\nsimulator navigation,\nscreenshot automation"];
    what -> "skills/tvos.md" [label="tvOS app,\nFocus Engine,\nSiri Remote, storage"];
}

1. Outdated Swift patterns / modern API replacements / Claude hallucinations? -> `skills/swift-modern.md` 2. ~Copyable / borrowing / consuming / InlineArray / Span? -> `skills/ownership-conventions.md` 3. Drag and drop / copy/paste / ShareLink / Transferable / UTTypes? -> `skills/transferable-ref.md` 4. Debug deep links / simulator navigation / screenshot automation? -> `skills/deep-link-debugging.md` 5. tvOS development / Focus Engine / Siri Remote / storage / AVPlayer? -> `skills/tvos.md` 6. Swift concurrency (async/await, actors, Sendable) -> `/skill axiom-concurrency` 7. Swift performance (COW, ARC, generics optimization) -> See axiom-performance (skills/swift-performance.md) 8. Codable patterns (JSON, CodingKeys, enum serialization) -> See axiom-data (skills/codable.md) 9. Simplify Swift for clarity (guard/optional cleanups, if/switch expressions, boilerplate)? -> `swift-simplifier` agent (`axiom-swift-simplifier`)

Conflict Resolution

**swift vs concurrency**: When Swift 6 concurrency errors appear:

• **Use concurrency, NOT swift** -- Concurrency errors are actor isolation / Sendable issues. `skills/swift-modern.md` covers concurrency *posture* (defaults), but detailed patterns live in axiom-concurrency.

**swift vs performance**: When optimizing Swift code:

• **Use swift for ownership** if the question is borrowing/consuming/~Copyable/InlineArray/Span -> `skills/ownership-conventions.md`
• **Use performance** if the question is COW, ARC profiling, generic specialization, or Instruments workflows -> axiom-performance

**swift vs swiftui**: When implementing drag and drop or copy/paste:

• **Use swift** for Transferable conformance, representation choices, UTType declarations -> `skills/transferable-ref.md`
• **Use swiftui** for view-level modifiers (.draggable, .dropDestination styling, animations)

**swift vs integration**: When sharing content:

• ShareLink + Transferable -> **use swift** (`skills/transferable-ref.md`)
• UIActivityViewController customization, share extensions -> **use integration**

**swift vs axiom-build**: When tvOS build fails:

• Environment/Xcode issues -> **use axiom-build first**
• tvOS platform-specific code issues (Focus Engine, storage, no WebView) -> **use swift** (`skills/tvos.md`)

Critical Patterns

**Modern Swift Idioms** (`skills/swift-modern.md`):

• 12+ outdated patterns Claude defaults to (Date(), CGFloat, DateFormatter, DispatchQueue.main.async)
• Foundation modernization (FormatStyle, URL.documentsDirectory, .replacing())
• SwiftUI convenience APIs Claude misses (ContentUnavailableView.search, LabeledContent)
• Swift 6.4 concurrency posture defaults
• 12+ common Claude hallucinations with corrections

**Ownersh