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 frontend-implementationgit 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/frontend-implementation)<a href="https://agentmods.dev/skills/lrinvl1203/world-class-web-design-os/frontend-implementation"><img src="https://agentmods.dev/badge/skills/lrinvl1203/world-class-web-design-os/frontend-implementation/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/frontend-implementation"><img src="https://agentmods.dev/badge/skills/lrinvl1203/world-class-web-design-os/frontend-implementation.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 | $0.00041 | $0.00310 |
| Opus 5.5 | $0.00016 | $0.00124 |
| Sonnet 5.5 | $0.00008 | $0.00062 |
| Haiku 4.5 | $0.00004 | $0.00031 |
Grade A, and why
frontend-implementation 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
Frontend Implementation
Preserve context
Inspect the repository before changing frameworks, routing, styling strategy or component foundations. Extend the existing stack unless a change has a clear user/maintenance benefit.
Build order
- semantic document and information hierarchy;
- responsive layout primitives;
- design-system tokens;
- functional states/interactions;
- imagery/media loading;
- motion/creative enhancement;
- QA instrumentation.
Engineering rules
- Prefer semantic HTML and native controls before recreating them.
- Keep component boundaries aligned to behavior/content responsibility, not every visual box.
- Use CSS Grid/Flex and fluid values before breakpoint proliferation.
- Reserve dimensions/aspect ratios for media to avoid layout shift.
- Subset/preload fonts intentionally; avoid loading families/weights not used.
- Keep server/client boundaries narrow in frameworks that support them.
- Lazy-load noncritical animation/3D code.
- Avoid global event listeners and per-frame React state updates for visual animation.
- Remove dead experimentation code and unused packages before release.
Visual fidelity
Do not “fix” a difficult art direction by reverting to standard cards. If a composition is hard to implement, solve the layout constraint or explicitly negotiate the tradeoff.
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 · 39 lines · 41 tokens per session scan A f0ef6d5adaaa
frontend-implementation is a skill published in the GitHub repository Lrinvl1203/world-class-web-design-os (8 stars, last pushed 22d ago), licensed MIT. It adds 41 tokens to every session and 310 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
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extract-design
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modular-scale-typography
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data-display-and-selection
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modal-and-overlay-patterns
Modals, drawers, bottom sheets and popovers, each with its scope and blocking level. Use when designing dialogs, confirmations, side panels or action sheets.