Getting it into your agent
It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.
git clone --depth 1 https://github.com/AThevon/genjutsunpx agentmods add skills/athevon/genjutsu/swiftui-motionWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/athevon/genjutsu/swiftui-motion)<a href="https://agentmods.dev/skills/athevon/genjutsu/swiftui-motion"><img src="https://agentmods.dev/badge/skills/athevon/genjutsu/swiftui-motion.svg" alt="Measured on agentmods" height="20"></a>- Socket pass
- Snyk pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00029 | $0.03655 |
| Opus 5 | $0.00015 | $0.01827 |
| Sonnet 5 | $0.00006 | $0.00731 |
| Haiku 4.5 | $0.00003 | $0.00365 |
Grade A, and why
swiftui-motion scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
89% identical to swiftui-motion — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 380 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SwiftUI Motion
SwiftUI animation core. Loaded for any SwiftUI project (iOS, macOS, multi-target Apple). Concise rules here. Deep-dive in
references/. Pair with../motion-principles/SKILL.md(foundation) and../mobile-principles/SKILL.md(touch UX).
Animation API decision tree
| Need | API |
|---|---|
| Single value over time | withAnimation { } + @State or .animation(_, value:) |
| Multiple coordinated states | PhaseAnimator(phases) (iOS 17+) |
| Time-based keyframes | KeyframeAnimator(initialValue:repeating:content:) (iOS 17+) |
| Custom property animations | @Animatable macro (iOS 26+) or Animatable protocol (iOS 13+) |
| Shared element transitions | matchedGeometryEffect(id:in:) |
| Gesture-driven | DragGesture / MagnifyGesture + .offset / .scaleEffect |
| Loop forever | .animation(.linear.repeatForever(autoreverses: true), value: ...) or .phaseAnimator |
Rule: start with withAnimation. Reach for PhaseAnimator only when you have 3+ ordered states. Reach for KeyframeAnimator only when you need parallel time-based tracks.
Springs (the only easing you should care about)
SwiftUI ships 4 named springs (iOS 17+). Use them. Tune response / dampingFraction only when a preset is wrong.
| Preset (iOS 17+) | Equivalent | Mood |
|---|---|---|
.snappy |
.spring(response: 0.5, dampingFraction: 0.85) |
UI snappy |
.bouncy |
.spring(response: 0.5, dampingFraction: 0.7) |
playful |
.smooth |
.spring(response: 0.5, dampingFraction: 1.0) |
calm, no bounce |
.interactiveSpring() |
.spring(response: 0.15, dampingFraction: 0.86) |
gesture follow |
response is the time the spring takes to settle (lower = snappier, higher = softer). dampingFraction is the overshoot intensity in 0...1 (1 = no overshoot, 0 = perpetual oscillation - never use 0). For UI work, stay in response: 0.2...0.5 and dampingFraction: 0.7...1.0. Deep-dive: references/springs-cheatsheet.md.
iOS 17+ also exposes .spring(duration:bounce:) where bounce is 0...1 (0 = critically damped, 1 = full bounce). It's the same spring, exposed in a more designer-friendly way:
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 7d ago First seen · 380 lines · 29 tokens per session scan A 7ace689f0937
swiftui-motion is a skill published in the GitHub repository AThevon/genjutsu (330 stars, last pushed 1mo ago), licensed MIT. It adds 29 tokens to every session and 3,655 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 89% identical to swiftui-motion, differing in 6 lines, and is treated as a copy.
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