audit-swiftui-animation-motion

name	audit-swiftui-animation-motion
description	Audit macOS SwiftUI animation motion for correctness, current APIs, and production conventions. Use for that domain or as part of a full audit.

Bundled resource root

Let <swiftui-plugin-root> be the absolute plugin directory two levels above this SKILL.md. Resolve that path before running commands or opening shared references. When these instructions say swiftui-ctx, invoke <swiftui-plugin-root>/scripts/swiftui-ctx; do not assume the command is on PATH.

Audit SwiftUI Animation & Motion

AUDIT-ONLY · macOS-only · SwiftUI-only. Run this on a finished or in-progress macOS SwiftUI project to detect — and where certain, flag — every way animation goes wrong: the deprecated implicit .animation(_), a missing/wrong value:, raw duration curves where spring presets fit, ungated macOS-14 spring presets / symbolEffect, hand-rolled loops that PhaseAnimator/KeyframeAnimator replace, missing contentTransition, mis-wired matchedGeometryEffect hero transitions, and motion that ignores Reduce Motion. Findings are written to disk in the toolkit's unified schema. This is never a from-scratch animation generator.

Boundary / seam note (stay in lane)

• The Liquid Glass morph itself (glassEffectID, GlassEffectContainer wiring) belongs to audit-swiftui-liquid-glass. This skill flags only a generic matchedGeometryEffect used on glassed views (anim-09) and cross_refs there — it does not audit glass-morph mechanics.
• Render cost of motion (per-frame redraw, .drawingGroup()) belongs to audit-swiftui-view-performance. This skill owns the UX-restraint verdict on .repeatForever (anim-11) and cross_refs the cost there.
• "The app ignores Reduce Motion entirely" across all surfaces belongs to audit-swiftui-accessibility; this skill owns the motion-specific missing reduced path (anim-10) and cross_refs it.
• Gesture-driven animation coupling belongs to audit-swiftui-pointer-gestures; TimelineView-as-clock drawing belongs to audit-swiftui-drawing-canvas. AppKit/Core Animation is out of scope entirely.

Domain rules (the spine)

1. Scope every implicit animation. .animation(_:value:) (or withAnimation) — never the deprecated single-arg .animation(_), which animates every upstream change.
2. Prefer the native primitive over the hand-rolled loop. Spring presets over raw durations (macOS 14), PhaseAnimator/KeyframeAnimator over Timer/repeatForever chains (macOS 14), symbolEffect over a hand-spun SF Symbol, contentTransition on value changes (macOS 13).
3. Motion is opt-out. Continuous/large motion must read accessibilityReduceMotion and degrade.
4. A hero transition needs all four wires — one shared @Namespace, matching id, a single transaction, one isSource.

Defect index (anim-01 … anim-11)

id · tell · severity · fix · open reference. Severities: hard-fail (availability break), warning (compiles but deprecated/non-native), advisory (judgment / restraint). flag = show the ✅, dev applies. No defect here is a mechanical single-answer rewrite, so all are fix_mode: flag-only (the animated value / curve / primitive is always a judgment).

id	One-line tell	Sev	Fix	Reference
anim-01	single-arg .animation(x) (deprecated implicit form, macOS 12)	warning	flag	animation-currency-and-springs.md
anim-02	.animation(_:value:) on a constant, or withAnimation over no observed change	warning	flag	animation-currency-and-springs.md
anim-03	raw .easeInOut(duration:)/.linear(duration:) where a spring preset fits	advisory	flag	animation-currency-and-springs.md
anim-04	spring preset .bouncy/.smooth/.snappy ungated under a < macOS 14 floor (locator: warn; a real availability break only when the deployment floor is < 14 — the agent escalates per the reference)	warning	flag	animation-currency-and-springs.md
anim-05	Timer/.repeatForever/repeatCount loop where PhaseAnimator/KeyframeAnimator fits	advisory	flag	phase-keyframe-and-symbol.md
anim-06	.symbolEffect ungated under < macOS 14, or a hand-animated SF Symbol	warning	flag	phase-keyframe-and-symbol.md
anim-07	a value change (numeric Text, swapped symbol) animates without .contentTransition	advisory	flag	phase-keyframe-and-symbol.md
anim-08	matchedGeometryEffect missing shared @Namespace / matching id / one transaction	warning	flag	hero-transitions-and-matched-geometry.md
anim-09	generic matchedGeometryEffect morphing glassed views (should be glassEffectID)	advisory	flag	hero-transitions-and-matched-geometry.md
anim-10	continuous/large motion ignores accessibilityReduceMotion (no reduced path)	warning	flag	reduce-motion-and-restraint.md
anim-11	.repeatForever / always-on motion — UX restraint	advisory	flag	reduce-motion-and-restraint.md

The spring-preset floor is UNVERIFIED-LOOKING but reconciled to macOS 14 — the shipped DocC renders macOS 10.15 (a type-property-inheritance quirk); the WWDC23 provenance is the truth. Carry macOS 14 for .bouncy/.smooth/.snappy (anim-04), never the rendered 10.15.

The real API, at a glance

Real (modern, prefer): animation(_:value:) (macOS 10.15+), withAnimation(_:_:), matchedGeometryEffect(id:in:…) (11+), contentTransition(_:) (13+), PhaseAnimator / KeyframeAnimator / symbolEffect(_:options:value:) / Animation.bouncy·.smooth·.snappy (all 14+), EnvironmentValues.accessibilityReduceMotion (10.15+). Deprecated: animation(_:) single-arg (deprecated at macOS 12 → animation(_:value:) / withAnimation).

Floor values are the reconciled truth in <swiftui-plugin-root>/references/_shared/floors-master.md and the invented-name list in <swiftui-plugin-root>/references/_shared/hallucination-blacklist.md — read, never restate them. Full ❌→✅ rewrites live in this skill's references/*.md.

The 8-step audit workflow (execute verbatim)

1. ORIENT. tree/find the SwiftUI sources. Read the deployment target (project.pbxproj MACOSX_DEPLOYMENT_TARGET, or Package.swift platforms:). Load-bearing: anim-04 (spring presets) and anim-06 (symbolEffect) fire only when the floor is below macOS 14. Record it.

2. LOCATE. Run the shared hybrid lint runner: bash <swiftui-plugin-root>/scripts/swiftui-lint.sh --skill audit-swiftui-animation-motion --dir <sources> --json /tmp/anim.json --sarif /tmp/anim.sarif. It runs this skill's tier-1 grep tells (lint/grep-tells.tsv) + the tier-2 structural ast-grep rule (lint/ast-grep/anim-01-implicit-animation.yml — single-arg arity grep can't express), plus a per-file parse probe, and emits unified JSON + SARIF. Read its parse_warnings — a flagged file did not fully parse; READ those by hand. The runner only LOCATES — never treat a hit as a finding. Engine + rule-file format + degradation: <swiftui-plugin-root>/references/_shared/lint-architecture.md.

3. READ. Open every located file in full — never pattern-match-and-patch blind. The value: binding, the @Namespace identity, the gate scope, and whether a withAnimation body mutates observed state are invisible to grep. Build a per-file inventory: each animated view + its trigger state + its floor gate + its motion role.

4. DETECT. Apply the index. Assign each candidate a confidence; report a finding only at 100 % certainty (a single-arg .animation, an ungated preset under a <14 floor, a hero transition with two different namespaces).

5. VERIFY. For anything ≤ ~70 % confidence run both sources. (a) Practice — bash <swiftui-plugin-root>/scripts/swiftui-ctx lookup <api> --json (e.g. animation → consensus 92 % (_, value) / 7 % (_), symbolEffect → introduced_macos 14, matchedGeometryEffect → 93 % (id, in)); for the deprecation rule also swiftui-ctx deprecated <api>. Read consensus, deprecated+replacement, recommended permalink, introduced_macos, co_occurs_with. (b) Spec — confirm via Sosumi (curl -sSL https://sosumi.ai/<apple-path>; never WebFetch developer.apple.com); protocol in <swiftui-plugin-root>/references/_shared/sosumi-reference.md. Cross-check introduced_macos against floors-master.md. The CLI contract is <swiftui-plugin-root>/references/_shared/swiftui-ctx-reference.md. Promote with the citation or discard.

   • Deeper corpus evidence (the real Animation vocabulary). Before flagging a raw curve where a preset fits (anim-03) or backing a preset ✅ (anim-04), run bash <swiftui-plugin-root>/scripts/swiftui-ctx valueBuilders ease + lookup bouncy/smooth/snappy for the real spring presets, durations, and overloads — e.g. .bouncy ships in 405 uses across 92 repos (incl. the (duration, extraBounce) overload, jellyfin/Swiftfin), so it is consensus, not exotic. For a custom transition (anim-08) run bash <swiftui-plugin-root>/scripts/swiftui-ctx conformances ViewModifier (or Transition) for real conformers + permalinks (stable envelope, next_actions → file <id>); pair with swiftui-ctx lookup animation / examples withAnimation --shape.

6. REPORT. Write each confirmed finding (output contract below). One finding per file, zero-padded, ordered. Write the run's _index.md.

7. FIX. This domain is all fix_mode: flag-only — leave each finding open with the ✅ in ## Correct. The ✅ is not a hand-written snippet — it is the swiftui-ctx consensus shape backed by a real macOS-26 example fetched with bash <swiftui-plugin-root>/scripts/swiftui-ctx file <recommended.id> --smart whose GitHub permalink (plus the Sosumi doc:) goes in ## Source. The verified canonical .animation(_:value:) ✅ — the live swiftui-ctx consensus shape (_, value) (92 %), grounded in real corpus code, not a placeholder:

   // ✅ Correct — swiftui-ctx `lookup animation` consensus `(_, value)`; real example
   //    sindresorhus/Gifski `ex_7f40920aa8` (author_authority 1,013,769, 8,409★)
   Label("Copy", systemImage: "doc.on.doc")
       .opacity(isShowingSuccess ? 0 : 1)
       .disabled(isShowingSuccess)
       .animation(.easeInOut(duration: 0.3), value: isShowingSuccess)
   // permalink: https://github.com/sindresorhus/Gifski/blob/7f873856e2acd8b52e6681dee3aec31e6cab23e4/Gifski/Utilities.swift#L4974
   // doc: https://sosumi.ai/documentation/swiftui/view/animation
   

   Observe the fix-safety protocol (<swiftui-plugin-root>/references/_shared/fix-safety-protocol.md); never weaken a check.

8. DOUBLE-CHECK. Re-confirm every citation still resolves and still says the floor you reported. If a recommended rewrite would introduce a new tell (e.g. a spring preset now needs a macOS-14 gate), loop that file back to DETECT.

Confidence gating (load-bearing)

Report a finding only at 100 % certainty. Anything ≤ ~70 % goes to VERIFY (step 5) before it can become a finding — never emit a speculative finding. Everything here is fix_mode: flag-only.

Output contract

Inherits the toolkit's unified contract (full schema + body sections + frontmatter keys: <swiftui-plugin-root>/references/_shared/finding-schema.md — do not restate it). Specialized:

• Findings: swiftui-audits/animation-motion/<context>/NN-slug.md (one finding per file, zero-padded, ordered). Per-run index: swiftui-audits/animation-motion/_index.md.
• domain: animation-motion. Additive field motion_role (the animation's role — e.g. state-feedback, hero-transition, attention, ambient) per finding-schema.md §4. fix_mode is flag-only for every defect. availability reads from floors-master.md. source is an Apple URL + access date (via Sosumi) or verify against Xcode 26 SDK. Emit cross_ref on anim-09 (liquid-glass), anim-10 (accessibility), anim-11 (view-performance).

Starter <context> folders (file here when…):

<context>	File a finding here when…
implicit-and-currency/	a deprecated single-arg .animation, a dead value:, or a no-op withAnimation (anim-01, anim-02)
spring-and-curves/	a raw curve where a preset fits, or an ungated spring preset under a <14 floor (anim-03, anim-04)
phase-keyframe-symbol/	a hand-rolled loop, an ungated/avoidable symbolEffect, or a missing contentTransition (anim-05, anim-06, anim-07)
hero-transitions/	a mis-wired matchedGeometryEffect, or a generic effect that should be a glass morph (anim-08, anim-09)
reduce-motion-and-restraint/	motion that ignores Reduce Motion, or always-on .repeatForever (anim-10, anim-11)

New-folder rule: if a finding does not fit any existing context folder, create a new one under swiftui-audits/animation-motion/ with a lowercase-hyphen slug and note it in the run's _index.md. Prefer an existing folder when the fit is reasonable. Two runs over the same code produce structurally identical trees.

Reference routing

File	Open when
references/animation-currency-and-springs.md	the deprecated .animation(_), dead value:, raw-curve-vs-preset, the spring-preset floor quirk (anim-01/02/03/04)
references/phase-keyframe-and-symbol.md	hand-rolled loops vs PhaseAnimator/KeyframeAnimator, symbolEffect floor/use, missing contentTransition (anim-05/06/07)
references/hero-transitions-and-matched-geometry.md	the four hero-transition wires, and the glass-morph seam (anim-08/09)
references/reduce-motion-and-restraint.md	the Reduce-Motion path and .repeatForever restraint (anim-10/11)
lint/grep-tells.tsv + lint/ast-grep/*.yml	step LOCATE — this skill's declarative rule set fed to the shared runner (tier-1 grep + tier-2 single-arg structural rule); tune detection here

Shared toolkit references (point in, never restate):

Shared file	For
<swiftui-plugin-root>/references/_shared/floors-master.md	every floor/availability value (the reconciled truth; the spring-preset macOS-14 correction)
<swiftui-plugin-root>/references/_shared/hallucination-blacklist.md	the canonical invented-name list
<swiftui-plugin-root>/references/_shared/macos-arm-gating.md	the macOS-arm gating rule + wrong-arm failure (anim-04, anim-06)
<swiftui-plugin-root>/references/_shared/finding-schema.md	the unified finding schema + the motion_role additive field
<swiftui-plugin-root>/references/_shared/fix-safety-protocol.md	the fix-safety protocol (step 7)
<swiftui-plugin-root>/references/_shared/sosumi-reference.md	the Apple-doc spec fetch protocol (step 5 VERIFY)
<swiftui-plugin-root>/references/_shared/swiftui-ctx-reference.md	the practice-corpus CLI contract — lookup/deprecated/file --smart for the consensus shape + permalinked example (steps 5 VERIFY · 7 FIX)
<swiftui-plugin-root>/references/_shared/cross-ref-graph.md	seam ownership + cross_ref targets (anim-09/10/11)

Detection accelerator

bash <swiftui-plugin-root>/scripts/swiftui-lint.sh --skill audit-swiftui-animation-motion --dir <files-or-dir> [--json out.json] [--sarif out.sarif] — the toolkit's one shared hybrid lint engine, fed this skill's declarative rules: tier-1 grep tells (lint/grep-tells.tsv, anim-01…anim-11) + the tier-2 ast-grep structural rule (lint/ast-grep/anim-01-implicit-animation.yml — single-argument .animation arity grep cannot express). It runs a per-file parse probe, emits unified JSON + SARIF, emits warnings/advisories only (no hard-fail tells — nothing blocks the gate), and degrades to grep-only with a notice if ast-grep is unreachable (npx --package @ast-grep/cli ast-grep; faster: brew install ast-grep). It only LOCATES — always READ each hit in full before reporting (step 3). The thin scripts/anim-lint.sh forwards to this runner. Engine

• rule-file format + JSON/SARIF shape + safety rails: <swiftui-plugin-root>/references/_shared/lint-architecture.md.