Borrowing it
Nothing to install: this file belongs to cardstack/boxel. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/cardstack/boxel/main/.claude/skills/motion-pattern/SKILL.mdgit clone --depth 1 https://github.com/cardstack/boxelWrote 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/cardstack/boxel/motion-pattern)<a href="https://agentmods.dev/skills/cardstack/boxel/motion-pattern"><img src="https://agentmods.dev/badge/skills/cardstack/boxel/motion-pattern/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/cardstack/boxel/motion-pattern"><img src="https://agentmods.dev/badge/skills/cardstack/boxel/motion-pattern.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 | $0.00081 | $0.01372 |
| Opus 5.5 | $0.00032 | $0.00549 |
| Sonnet 5.5 | $0.00016 | $0.00274 |
| Haiku 4.5 | $0.00008 | $0.00137 |
Grade A, and why
motion-pattern 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 5d 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.
How it starts
The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Choosing the animation pattern
The library is two layers, one package each:
- The binding (
glimmer-motion,packages/glimmer-motion) — Motion's engine (motion-dom, untouched) driven through Glimmer: the{{motion}}modifier plus<Presence>,<LayoutGroup>,<MotionConfig>,<ReorderGroup>/<ReorderItem>. - Choreo (
@cardstack/choreo,packages/choreo) — a region-scoped model on top:<Choreo>watches a render pass, hands you its changeset (inserted / removed / kept, with bounds before and after), and plays a declared timeline over it.
Pick the smallest pattern that states the intent. Escalation order: element → presence → layout → Choreo. Page transitions and scroll are side doors, not steps on that ladder.
Decision table
| The ask sounds like | Pattern | Skill |
|---|---|---|
| "fade/slide/scale this in", hover/tap states, keyframes, variants, stagger | {{motion}} with initial/animate/transition |
motion-element |
| "animate it when it's removed", toasts, list add/remove, modal open/close | <Presence> + exit |
motion-presence |
| "it moved because the layout changed", tab indicator, thumbnail → detail of the SAME thing | layout=true / layoutId / <LayoutGroup> |
motion-layout |
| "first X, THEN everyone moves, THEN Y" — ordering across several elements; z-index for the span of a move; one element's motion computed from another's box; fly to a place that must not deform | <Choreo> timeline (+ {{beacon}}, both from @cardstack/choreo) |
choreo-scene |
more than one <Choreo> in a tree; an element flying from one region into another (Boxel card between panels) |
nested regions + far matching | choreo-regions |
| Route/page change | Live DOM crossing: <Choreo @route>; intentional snapshots: animateView |
magic-move-navigation / motion-page-transition |
| the gallery-card ⇄ demo-page shared-element navigation, or porting that Magic Move recipe | <Choreo @route> + paired identities |
magic-move-navigation |
| drag, swipe-to-dismiss, reorderable list/grid, bottom sheet | drag / <ReorderGroup> |
motion-drag |
| parallax, scroll progress, reveal-on-scroll, hide-on-scroll header | scrollProgress / InView |
motion-scroll |
| writing or fixing a test that involves motion | glimmer-motion/test-support |
motion-testing |
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.
- 5d ago First seen · 87 lines · 81 tokens per session scan A 9f7dc88d0d47
motion-pattern is a skill published in the GitHub repository cardstack/boxel (27 stars, last pushed today), licensed MIT. It adds 81 tokens to every session and 1,372 once invoked, about $0.0003 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 2026-10-21.
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