Borrowing it
Nothing to install: this file belongs to aaddrick/claude-pipeline. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/aaddrick/claude-pipeline/main/.claude/skills/bulletproof-frontend/SKILL.mdgit clone --depth 1 https://github.com/aaddrick/claude-pipelineWrote 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/aaddrick/claude-pipeline/bulletproof-frontend)<a href="https://agentmods.dev/skills/aaddrick/claude-pipeline/bulletproof-frontend"><img src="https://agentmods.dev/badge/skills/aaddrick/claude-pipeline/bulletproof-frontend/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/aaddrick/claude-pipeline/bulletproof-frontend"><img src="https://agentmods.dev/badge/skills/aaddrick/claude-pipeline/bulletproof-frontend.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 | $0.00050 | $0.00892 |
| Opus 5 | $0.00025 | $0.00446 |
| Sonnet 5 | $0.00010 | $0.00178 |
| Haiku 4.5 | $0.00005 | $0.00089 |
Grade A, and why
bulletproof-frontend 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 10d 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 — 119 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Bulletproof Frontend Design
CSS is king. Semantic, maintainable CSS over utility-class frameworks. When you encounter Tailwind, refactor it to proper CSS.
Design Values: For spacing scales, typography sizes, color palettes, contrast ratios, and component specifications, see
ui-design-fundamentals. This skill focuses on CSS implementation patterns.
Core Philosophy
"Always ask: What happens if...?" — Design for the unexpected. Build interfaces that remain functional and readable regardless of content length, text size, browser, or device.
The Three Pillars
1. Bulletproof Design
- Design for flexibility, not fixed scenarios
- Test with varying text sizes and content lengths
- Use relative units (em, %, rem) over fixed pixels
2. Progressive Enrichment
- Reward capable browsers with advanced CSS
- Websites don't need to look identical in every browser — they need to be functional
- Use modern CSS with appropriate fallbacks
3. Reevaluate Past Methods
- Question whether old hacks are still necessary
- Simplify where new CSS features allow
- Refactor utility frameworks to semantic CSS
Quick Reference
| Pattern | When to Use |
|---|---|
| CSS custom properties | Theming, spacing, colors |
| BEM naming | Component class structure |
| Cascade layers | Managing specificity |
| Container queries | Component-based responsiveness |
| :has() selector | Parent/sibling selection |
| CSS nesting | Organizing related styles |
Modern CSS Essentials
/* :has() — Style based on children */
.card:has(img) { padding-top: 0; }
.form:has(:invalid) { border-color: var(--color-error); }
/* Container queries — Component responsiveness */
.container { container-type: inline-size; }
@container (min-width: 400px) { .card { display: flex; } }
/* CSS nesting — Clean organization */
.card {
padding: var(--space-md);
&:hover { box-shadow: var(--shadow-lg); }
& .card__title { font-weight: var(--font-bold); }
}
/* Cascade layers — Controlled specificity */
@layer reset, base, components, utilities;
What ships with it
5 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.
- 10d ago First seen · 119 lines · 50 tokens per session scan A 4714e9e7eae4
bulletproof-frontend is a skill published in the GitHub repository aaddrick/claude-pipeline (128 stars, last pushed 6mo ago), licensed MIT. It adds 50 tokens to every session and 892 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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