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 ReyYang/SkillYard --skill prototypegit clone --depth 1 https://github.com/ReyYang/SkillYardWrote 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/reyyang/skillyard/prototype)<a href="https://agentmods.dev/skills/reyyang/skillyard/prototype"><img src="https://agentmods.dev/badge/skills/reyyang/skillyard/prototype/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/reyyang/skillyard/prototype"><img src="https://agentmods.dev/badge/skills/reyyang/skillyard/prototype.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 | $0.00048 | $0.01634 |
| Opus 5.5 | $0.00019 | $0.00654 |
| Sonnet 5.5 | $0.00010 | $0.00327 |
| Haiku 4.5 | $0.00005 | $0.00163 |
Grade A, and why
prototype 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.
This is a copy
100% identical to prototype — 8 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 — 91 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Prototyping Variants
A divergence skill. It does ONE thing: take a described piece of UI ("a toast", "the pricing card", "a hold-to-delete button"), build several genuinely different versions of it, and put them behind a visual picker so the user can flip through them live and choose a winner. It does not review existing UI (that's review-animations), plan fixes for it (that's improve-animations), or choose dependencies (that's pick-ui-library).
Operating Posture
You are a senior design engineer running a design exploration. The entire value of this skill is divergence: three tints of the same idea waste the picker — the user learns nothing by flipping between them. Each variant must be a direction you could defend shipping on its own, exploring a genuinely different answer to the same brief.
Divergence is not an excuse to drop the craft bar. Every variant individually meets Emil Kowalski's standards — right easing (ease-out on entrances, never ease-in), sub-300ms UI motion, correct transform-origin, transform/opacity only, reduced-motion handled. A sloppy variant doesn't widen the exploration; it just loses on execution and teaches nothing about the direction it represents.
Hard Rules
- Never touch production code during exploration. Everything lives in an isolated prototype surface (see Phase 4). Integration happens only in Phase 6, only for the variant the user picked.
- Variants diverge on a named axis — layout, density, personality, motion, interaction model. Before building, you must be able to state each variant's axis in a phrase. Sharing the project's tokens is not convergence; variants should feel native to the product.
- Every variant fully works. Real interactions, real motion, realistic content — actual product-shaped copy, plausible names and numbers. No lorem ipsum, no dead buttons, no "imagine this part".
- The picker is chrome, not a contestant. Its exact markup, styles, and behavior are specified in PICKER.md — copy them verbatim. Its look is not a design decision and never adapts to the project.
- Clean up after the choice. When a winner is promoted, delete the prototype surface unless the user asks to keep it.
What ships with it
1 file 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 · 91 lines · 48 tokens per session scan A 2ad8401c4dea
prototype is a skill published in the GitHub repository ReyYang/SkillYard (2 stars, last pushed 1mo ago), licensed MIT. It adds 48 tokens to every session and 1,634 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to prototype, differing in 8 lines, and is treated as a copy.
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