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 agentmods add skills/monkilabs/opencastle/frontend-designnpx skills add monkilabs/opencastle --skill frontend-designgit clone --depth 1 https://github.com/monkilabs/opencastleWrote 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/monkilabs/opencastle/frontend-design)<a href="https://agentmods.dev/skills/monkilabs/opencastle/frontend-design"><img src="https://agentmods.dev/badge/skills/monkilabs/opencastle/frontend-design.svg" alt="Measured on agentmods" 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 | $0.00068 | $0.00330 |
| Opus 5 | $0.00034 | $0.00165 |
| Sonnet 5 | $0.00014 | $0.00066 |
| Haiku 4.5 | $0.00007 | $0.00033 |
Grade A, and why
frontend-design 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.
What it actually says
Design Workflow
- Name the aesthetic in 2–3 words in a comment at the top of the main CSS file; commit to it.
- Define every color, space, and radius as a
:rootcustom property; build components from those tokens only — no ad-hoc values. - Wrap entrance animations in
@media (prefers-reduced-motion: no-preference); keep key animations under 500ms. - Verify before marking done: contrast ≥4.5:1 body text and ≥3:1 large text, no overflow at mobile sizes.
Every design must have one unforgettable detail. No two designs should look alike.
Card patterns, hero animations, extended token sets: COMPONENTS.md. Design principles, typography catalogue, example constraints: REFERENCE.md.
Typography
Always ship a metric-preserving fallback chain (e.g. 'Fraunces', 'Georgia', serif).
Load project-consistency skill for the full Foundation Phase pattern and prompt templates.
What ships with it
2 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.
- 5d ago First seen · 24 lines · 68 tokens per session scan A c594e0b9bb34
frontend-design is a skill published in the GitHub repository monkilabs/opencastle (61 stars, last pushed 7d ago), licensed MIT. It adds 68 tokens to every session and 330 once invoked, about $0.0003 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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