Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add Lrinvl1203/world-class-web-design-os --skill motion-enginegit clone --depth 1 https://github.com/Lrinvl1203/world-class-web-design-osWrote 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/lrinvl1203/world-class-web-design-os/motion-engine)<a href="https://agentmods.dev/skills/lrinvl1203/world-class-web-design-os/motion-engine"><img src="https://agentmods.dev/badge/skills/lrinvl1203/world-class-web-design-os/motion-engine/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.
<a href="https://agentmods.dev/skills/lrinvl1203/world-class-web-design-os/motion-engine"><img src="https://agentmods.dev/badge/skills/lrinvl1203/world-class-web-design-os/motion-engine.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00047 | $0.00387 |
| Opus 5.5 | $0.00019 | $0.00155 |
| Sonnet 5.5 | $0.00009 | $0.00077 |
| Haiku 4.5 | $0.00005 | $0.00039 |
Grade A, and why
motion-engine 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 1mo 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.
What it actually says
Motion Engine
Rule: intent first, engine second
Read references/tool-router.md and references/capability-matrix-2026.md and choose the smallest engine that cleanly implements the interaction.
Native first
Use CSS transitions/keyframes, WAAPI, CSS Scroll-Driven Animations or View Transitions when they cover the behavior cleanly.
Motion
Prefer for React state/layout/shared-layout, presence, gestures, springs and common scroll-linked UI motion. Read references/motion.md.
Anime.js
Prefer for precise lightweight timelines, staggered choreography, SVG/text/value animation and deterministic sequencing. Read references/animejs.md.
GSAP
Prefer for advanced multi-part timelines, ScrollTrigger pin/scrub, Flip, SplitText, MotionPath and complex scroll/DOM/3D orchestration. Read references/gsap-lenis.md.
Lenis
Use only when smooth scrolling or a normalized scroll signal is an intentional part of the experience. Native scroll remains the default.
Cross-engine discipline
- Do not install two engines that solve the same job unless distinct capabilities are actively used.
- If multiple systems animate in the same frame, coordinate update loops rather than creating uncontrolled RAF competition.
- Preserve logical state when motion is disabled.
- Keep transform/opacity animation compositor-friendly where possible; avoid layout thrash in scroll handlers.
- Pause offscreen or nonessential animation.
Output
For notable motion, record: Intent → Engine → Why → Reduced-motion behavior → Performance risk.
What ships with it
6 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.
- 1mo ago First seen · 40 lines · 47 tokens per session scan A 94eee7501071
motion-engine is a skill published in the GitHub repository Lrinvl1203/world-class-web-design-os (8 stars, last pushed 22d ago), licensed MIT. It adds 47 tokens to every session and 387 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-31.
Other skills, from other repositories
brand-visual-language
Shape language across type, radius and icons carries brand personality. Use when starting a design system, picking icons or radius tokens, or reviewing visual consistency.
loading-states-and-perceived-performance
Spinners, skeletons and staggered reveals that manage wait times. Use when designing loading states, async data or the feel of a slow interface.
micro-interactions
Small purposeful animations — toggles, animated icons, success moments. Use when designing interactive feedback, success states or loaders.
color-mode-and-theme
Light, dark or both, and when a theme selector is worth it. Use when defining a base palette or deciding on dark mode support.
elevation-and-depth
Shadows and layering that lift elements above the surface. Use when designing cards, dropdowns, modals, tooltips or any floating element.
motion-and-storytelling
Disney's animation principles and cinematic technique applied to UI motion. Use when designing transitions, scroll animations or onboarding motion.