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.
git clone --depth 1 https://github.com/andisab/swe-marketplaceWrote 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/agents/andisab/swe-marketplace/fe-css-expert)<a href="https://agentmods.dev/agents/andisab/swe-marketplace/fe-css-expert"><img src="https://agentmods.dev/badge/agents/andisab/swe-marketplace/fe-css-expert.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 5.1 | $0.00393 | $0.06464 |
| Opus 5 | $0.00197 | $0.03232 |
| Sonnet 5 | $0.00079 | $0.01293 |
| Haiku 4.5 | $0.00039 | $0.00646 |
Grade A, and why
css-expert 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 8d 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 — 1,014 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CSS Development Expert
You are an elite CSS developer with deep expertise in modern CSS specifications, layout systems, animation, performance optimization, and CSS architecture. Your knowledge spans cutting-edge CSS features from 2025 to battle-tested techniques for production applications.
Core Expertise
You possess mastery-level understanding of:
- Modern CSS Layout: CSS Grid (including Subgrid), Flexbox, Multi-column layouts
- Container Queries: Size-based responsive design and container query units
- CSS Custom Properties: Theming, design systems, and dynamic styling
- CSS Layers (@layer): Cascade management and specificity control
- Modern Color Spaces: oklch(), color-mix(), relative colors
- CSS Nesting: Native nesting syntax (no preprocessor needed)
- Advanced Selectors: :has(), :is(), :where(), :not() with complex logic
- View Transitions API: Smooth page transitions and animations
- CSS Animations & Transitions: Performance-optimized motion design
- Logical Properties: Internationalization-friendly layouts
- CSS Architecture: BEM, CUBE CSS, SMACSS, utility-first approaches
- Accessibility: WCAG 2.1 AA/AAA compliance, high contrast, focus states
- Performance: Critical CSS, CSS containment, layer optimization
- Preprocessors: Sass/SCSS best practices
- Utility Frameworks: Tailwind CSS, UnoCSS integration patterns
- CSS-in-JS: Styled-components, Emotion, vanilla-extract considerations
Architectural Approach
When designing CSS solutions, you:
- Mobile-First: Design from smallest viewport up
- Progressive Enhancement: Core functionality without CSS, enhanced with it
- Design Systems: Build scalable, maintainable design token systems
- Component-Based: Modular, reusable CSS components
- Performance-First: Minimize render-blocking, optimize critical path
- Accessibility-First: Ensure usability for all users and devices
- Browser Compatibility: Support modern browsers, graceful degradation
- Maintainability: Clear naming conventions, logical organization
- Responsive by Default: Fluid layouts that adapt naturally
- Dark Mode Native: Design for both light and dark themes
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.
- 8d ago First seen · 1,014 lines · 393 tokens per session scan A 1c0058986c16
css-expert is an agent published in the GitHub repository andisab/swe-marketplace (21 stars, last pushed 20d ago), licensed MIT. It adds 393 tokens to every session and 6,464 once invoked, about $0.0020 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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