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 vanja-emichi/a0_agent_skills --skill frontend-ui-engineeringgit clone --depth 1 https://github.com/vanja-emichi/a0_agent_skillsWrote 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/vanja-emichi/a0_agent_skills/frontend-ui-engineering)<a href="https://agentmods.dev/skills/vanja-emichi/a0_agent_skills/frontend-ui-engineering"><img src="https://agentmods.dev/badge/skills/vanja-emichi/a0_agent_skills/frontend-ui-engineering/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/vanja-emichi/a0_agent_skills/frontend-ui-engineering"><img src="https://agentmods.dev/badge/skills/vanja-emichi/a0_agent_skills/frontend-ui-engineering.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 | $0.02648 |
| Opus 5 | $0.00024 | $0.01324 |
| Sonnet 5 | $0.00010 | $0.00530 |
| Haiku 4.5 | $0.00005 | $0.00265 |
Grade A, and why
frontend-ui-engineering 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 9d 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 — 359 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend UI Engineering
Supporting files: This skill has a companion accessibility checklist. Use
text_editor:readwith the full path shown in the file tree when this skill is loaded to openaccessibility-checklist.md(sibling to this SKILL.md).
Overview
Build production-quality user interfaces that are accessible, performant, and visually polished. The goal is UI that looks like it was built by a design-aware engineer at a top company — not like it was generated by an AI. This means real design system adherence, proper accessibility, thoughtful interaction patterns, and no generic "AI aesthetic."
When to Use
- Building new UI components or pages
- Modifying existing user-facing interfaces
- Implementing responsive layouts
- Adding interactivity or state management
- Fixing visual or UX issues
Component Architecture
File Structure
Colocate everything related to a component:
src/components/
TaskList/
TaskList.tsx # Component implementation
TaskList.test.tsx # Tests
TaskList.stories.tsx # Storybook stories (if using)
use-task-list.ts # Custom hook (if complex state)
types.ts # Component-specific types (if needed)
Component Patterns
Prefer composition over configuration:
// Good: Composable
<Card>
<CardHeader>
<CardTitle>Tasks</CardTitle>
</CardHeader>
<CardBody>
<TaskList tasks={tasks} />
</CardBody>
</Card>
// Avoid: Over-configured
<Card
title="Tasks"
headerVariant="large"
bodyPadding="md"
content={<TaskList tasks={tasks} />}
/>
Keep components focused:
export function TaskItem({ task, onToggle, onDelete }: TaskItemProps) {
return (
<li className="flex items-center gap-3 p-3">
<Checkbox checked={task.done} onChange={() => onToggle(task.id)} />
<span className={task.done ? 'line-through text-muted' : ''}>{task.title}</span>
<Button variant="ghost" size="sm" onClick={() => onDelete(task.id)}>
<TrashIcon />
</Button>
</li>
);
}
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.
- 9d ago First seen · 359 lines · 48 tokens per session scan A a10c17357220
frontend-ui-engineering is a skill published in the GitHub repository vanja-emichi/a0_agent_skills (5 stars, last pushed 1mo ago), licensed MIT. It adds 48 tokens to every session and 2,648 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.
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