Borrowing it
Nothing to install: this file belongs to matteocervelli/llms. 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/matteocervelli/llms/main/.claude/skills/frontend/SKILL.mdgit clone --depth 1 https://github.com/matteocervelli/llmsWrote 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/matteocervelli/llms/frontend)<a href="https://agentmods.dev/skills/matteocervelli/llms/frontend"><img src="https://agentmods.dev/badge/skills/matteocervelli/llms/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/matteocervelli/llms/frontend"><img src="https://agentmods.dev/badge/skills/matteocervelli/llms/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 | $0.00072 | $0.02686 |
| Opus 5.5 | $0.00029 | $0.01074 |
| Sonnet 5.5 | $0.00014 | $0.00537 |
| Haiku 4.5 | $0.00007 | $0.00269 |
Grade A, and why
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 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.
How it starts
The opening of the file, as written. The whole thing — 258 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend — Design, Build & Verify
Unified frontend skill for visual design, component creation, E2E testing, accessibility audits, and visual review. Composes five design dimensions with tech-specific implementations.
Usage
/frontend # Show dimensions, suggest next action
/frontend design # 6 design dimensions + 9-phase workflow
/frontend component <name> # Create UI component with variants, tests, preview
/frontend e2e # Write Playwright E2E tests (page object model)
/frontend a11y # WCAG 2.1 AA accessibility audit
/frontend review # Gemini visual review (screenshot + code)
/frontend verify # Quick verification decision tree
Workflow
Step 1: Determine Mode
Parse $ARGUMENTS for explicit subcommand. If no arguments:
- Check for recent frontend file changes (
*.html,*.css,*.ts,*.tsx,*.jinja2,*.scss) - If changes found → suggest
/frontend verify - If new project → suggest
/frontend design - Otherwise → show all modes
Step 1.5: Load Design System
Before routing to any subcommand, check for a persistent design system file:
- Look for
.design/system.mdin the project root (search from CWD upward, stop at git root) - If found: read it and announce →
Design system loaded: [list the Mode + Typography + Color + Depth values] - Treat the loaded values as hard constraints throughout the session — do not contradict them without explicitly noting you're changing a decision and logging it
On /frontend design Phase 1 completion:
- Create
.design/system.mdif it does not exist (use the Design Brief output as seed) - If it exists: update only the fields changed in this session; preserve existing Decisions Log entries
- Note:
.design/system.mdshould be committed to version control (it is a project artifact)
After each design phase (typography, color, spatial, etc.):
- Update the corresponding section in
.design/system.mdwith the decisions made
What ships with it
60 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.
- design-references/color-palettes/gradients-patterns.md 5.6 KB
- design-references/color-palettes/ide-themes.json 8.7 KB
- design-references/motion-patterns/css-animations.json 8.3 KB
- design-references/motion-patterns/framer-motion-variants.md 5.5 KB
- design-references/spatial-compositions/asymmetry-guide.md 4.9 KB
- design-references/spatial-compositions/layout-patterns.json 12 KB
- design-references/typography/anti-patterns.md 3.3 KB
- design-references/typography/font-pairings.json 5.8 KB
- design-references/typography/size-scales.md 2.8 KB
- design-references/typography/weight-scales.json 5.6 KB
- design-systems/custom-test-design-system/metadata.json 226 B
- design-systems/custom-test-design-system/tokens.json 788 B
- prompts/aesthetics-base.md 6.4 KB
- prompts/anti-patterns.md 11 KB
- prompts/design-thinking.md 12 KB
- prompts/litmus-checks.md 3.2 KB
- prompts/motion.md 8.4 KB
- prompts/typography.md 6.6 KB
- README.md 7.7 KB
- scripts/design-lint.sh 3.7 KB runs code
- sub-skills/backgrounds.md 7.4 KB
- sub-skills/color-theme.md 5.7 KB
- sub-skills/css-scss.md 5.0 KB
- sub-skills/design-thinking.md 5.2 KB
- sub-skills/htmx.md 4.4 KB
- sub-skills/hugo.md 5.4 KB
- sub-skills/imagery.md 3.2 KB
- sub-skills/jinja2.md 4.6 KB
- sub-skills/material-design.md 4.6 KB
- sub-skills/motion.md 7.9 KB
- sub-skills/page-composition.md 4.7 KB
- sub-skills/radix-ui.md 4.3 KB
- sub-skills/react-vite.md 4.3 KB
- sub-skills/sass.md 5.6 KB
- sub-skills/shadcn-ui.md 3.7 KB
- sub-skills/spatial.md 7.0 KB
- sub-skills/tailwind.md 3.3 KB
- sub-skills/typescript.md 5.5 KB
- sub-skills/typography.md 4.7 KB
- sub-skills/ui-polish.md 12 KB
- templates/a11y/accessibility-report.md 3.5 KB
- templates/a11y/wcag-checklist.md 11 KB
- templates/component-scaffold.md 3.5 KB
- templates/e2e/api-mocking.ts 5.8 KB runs code
- templates/e2e/auth-setup.ts 3.4 KB runs code
- templates/e2e/custom-fixtures.ts 2.7 KB runs code
- templates/e2e/page-object-model.ts 3.7 KB runs code
- templates/e2e/playwright-config.ts 1.2 KB runs code
- templates/e2e/responsive-tests.ts 3.7 KB runs code
- templates/e2e/visual-regression.ts 4.3 KB runs code
- tests/test-design-lint/fixtures/clean.css 393 B
- tests/test-design-lint/fixtures/violations.css 262 B
- tests/test-design-lint/fixtures/violations.tsx 256 B
- tests/test-design-lint/test-lint.sh 2.7 KB runs code
- tools/design_system_fetcher/__init__.py 654 B runs code
- tools/design_system_fetcher/__main__.py 182 B runs code
- tools/design_system_fetcher/fetcher.py 5.4 KB runs code
- tools/design_system_fetcher/main.py 7.9 KB runs code
- tools/design_system_fetcher/README.md 6.1 KB
- tools/design_system_fetcher/storage.py 10 KB runs code
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 · 258 lines · 72 tokens per session scan A 4ad9bb38ad71
frontend is a skill published in the GitHub repository matteocervelli/llms (25 stars, last pushed 5mo ago), licensed MIT. It adds 72 tokens to every session and 2,686 once invoked, about $0.0003 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 2026-09-03.
Other skills, from other repositories
verify-omnigent
Drive Omnigent the way a user does and prove a behavior with recorded evidence, using an isolated server, runner, and mock model plus a feature map of every user entry point. Load before reproducing a user-facing bug, before claiming a fix works, or when reviewing whether a change covered every surface (session vs.…
test-master
Generates test files, creates mocking strategies, analyzes code coverage, designs test architectures, and produces test plans and defect reports across functional, performance, and security testing disciplines. Use when writing unit tests, integration tests, or E2E tests; creating test strategies or automation…
eval-dataset-design
A guide to creating reliable test sets for AI agents. Each evaluation task includes the request, the simulated user's behaviour, a reset starting state, and a success check that can be independently verified.
dogfood
Systematically explore and test a mobile app on iOS/Android with agent-device to find bugs, UX issues, and other problems. Use when asked to dogfood, QA, exploratory test, find issues, bug hunt, or test this app on mobile.
cua-driver
Use Cua Driver for desktop or browser tasks that are awkward or unavailable through Bash/APIs, or when the user explicitly wants GUI interaction: app testing, visual bug reproduction, form filling, calendar entry, screenshots, and demo recording. Also covers Cua setup; not OpenAI Codex Computer Use or web research.
critique
Adversarial design critique of the current work. Render it, look at it, and argue for rejection. Run after the gates are green, never instead of them.