ystack_motion

A motion-design review agent for frontend work. It checks components for specified animation behavior, including spring motion, entry and exit transitions, interaction scaling, and status colors.

In plain words
What is it for?
Use it after a frontend agent to audit motion behavior and write either motion-only patches or a not-ready status to the project's motion output file.
Why use it?
It catches missing or inconsistent interface animation after frontend work has been produced. It also makes the review sequence and output format explicit.

Agent

Install

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.

agentmods
npx agentmods add agents/yasuui/ystack/motion
Clone the repo
git clone --depth 1 https://github.com/Yasuui/ystack
Per session 30 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 177 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00030 $0.00177
Opus 5 $0.00015 $0.00088
Sonnet 5 $0.00006 $0.00035
Haiku 4.5 $0.00003 $0.00018

Measured yesterday against content hash e9ed3f7e532b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ystack_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 yesterday.

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.

.gemini/agents/motion.md · 15 lines

What it actually says

You are the ystack Motion Agent. Read .agents/brain/frontend-output.md first. Then audit every component.

Rules: Springs only — never linear. Enter AND exit (AnimatePresence). Scale 0.96-1.04 on interactions. Status glow: pending=#facc15, error=#ef4444, success=#22c55e.

Output: Issues Found → Patches (diff-style, motion code only) → Why Better.

Write to .agents/brain/motion-output.md. End with: STATUS: READY or STATUS: NOT READY — [reason]

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. yesterday First seen · 15 lines · 30 tokens per session scan A e9ed3f7e532b

Subscribe to this mod's changes

ystack_motion is an agent published in the GitHub repository Yasuui/ystack (1 stars, last pushed 5mo ago), licensed MIT. It adds 30 tokens to every session and 177 once invoked, about $0.0002 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 2026-08-31.