Tracely-ai: Skill for Claude Code

.agents/skills/swiftui-motion/SKILL.md

swiftui-motion is a skill for Claude Code, Codex from Jwuthri/Tracely-ai. It costs 29 tokens per session (3,636 once invoked), scanned A, original, MIT.

A guide to adding motion effects in SwiftUI, Apple's framework for building app interfaces. It covers animations, transitions, shared-element effects, springs, keyframes, and gesture-driven movement.

In plain words
What is it for?
Animating views, coordinating several states, creating timed or repeating effects, moving elements with gestures, and building transitions for iOS or macOS apps.
Why use it?
It helps choose the appropriate SwiftUI animation method for a specific interface behavior.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is Jwuthri/Tracely-ai's own configuration. It tells Claude Code and Codex how to work on Tracely-ai itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Tracely-ai configures →

Needs its repository: it reads a path above its own folder, which exists only inside the repository. The line is Pair with `../motion-principles/SKILL.md` (foundation) and `../mobile-principles/SKILL.md` (touch UX)..

About the project

Tracely is a CI/CD system for AI agents that turns failed production traces into replayable regression tests. Development teams use it to detect and group agent failures, run the resulting cases on pull requests, and block changes that reproduce those failures. The catalogue entries provide skills for operating this trace-based testing and observability workflow.

Jwuthri/Tracely-ai · 1,216 stars · on GitHub · tracely-ai.com

Reuse

Borrowing it

Nothing to install: this file belongs to Jwuthri/Tracely-ai. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Jwuthri/Tracely-ai/master/.agents/skills/swiftui-motion/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Jwuthri/Tracely-ai

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for swiftui-motion

README.md
[![agentmods](https://agentmods.dev/badge/skills/jwuthri/tracely-ai/swiftui-motion/github.svg)](https://agentmods.dev/skills/jwuthri/tracely-ai/swiftui-motion)
Your own site
<a href="https://agentmods.dev/skills/jwuthri/tracely-ai/swiftui-motion"><img src="https://agentmods.dev/badge/skills/jwuthri/tracely-ai/swiftui-motion/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for swiftui-motion

Your own site · 80×15
<a href="https://agentmods.dev/skills/jwuthri/tracely-ai/swiftui-motion"><img src="https://agentmods.dev/badge/skills/jwuthri/tracely-ai/swiftui-motion.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,636 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 24
    Skill allows unbounded resource consumption (API calls, storage, compute). Without rate limits or quotas, a compromised or misbehaving agent can cause denial-of-service or cost overruns.
    Fix: Set explicit rate limits, timeouts, and resource quotas for API calls, file operations, and compute. Implement circuit breakers for runaway loops.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00029 $0.03636
Opus 5 $0.00015 $0.01818
Sonnet 5 $0.00006 $0.00727
Haiku 4.5 $0.00003 $0.00364

Measured 9d ago against content hash ebb33de86975, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

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 9d 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.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

.agents/skills/swiftui-motion/SKILL.md · 380 lines

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 17+) or Animatable protocol
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: 0.3, 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:

Read the full file on GitHub · 380 lines

Files

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.

Changes

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.

  1. 9d ago First seen · 380 lines · 29 tokens per session scan A ebb33de86975

Subscribe to this mod's changes

swiftui-motion is a skill published in the GitHub repository Jwuthri/Tracely-ai (1,216 stars, last pushed 2d ago), licensed MIT. It adds 29 tokens to every session and 3,636 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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