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 agentmods add skills/martian56/claude-engineer/frontend-developmentnpx skills add martian56/claude-engineer --skill frontend-developmentgit clone --depth 1 https://github.com/martian56/claude-engineerWrote 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/martian56/claude-engineer/frontend-development)<a href="https://agentmods.dev/skills/martian56/claude-engineer/frontend-development"><img src="https://agentmods.dev/badge/skills/martian56/claude-engineer/frontend-development.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 | $0.00059 | $0.00644 |
| Opus 5 | $0.00030 | $0.00322 |
| Sonnet 5 | $0.00012 | $0.00129 |
| Haiku 4.5 | $0.00006 | $0.00064 |
Grade A, and why
frontend-development 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 5d 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 — 43 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend Development
Announce at start: "I'm using claude-engineer:frontend-development to build the frontend on the blessed stack."
React vs Next.js (default decision)
- Next.js (App Router) for marketing/content sites and content+app hybrids (SEO, RSC, server data).
- Vite SPA (React) for dashboards/SaaS behind auth and design-system/library work (no SEO need).
- Rule of thumb: anonymous crawler needs real content, or you need a server data layer → Next.js; everything behind a login and API-bound → Vite SPA.
Blessed libraries (June 2026 defaults - full table + versions in references/frontend-stack.md)
| Need | Default |
|---|---|
| UI primitives | shadcn/ui (own the code) over Radix/Base UI |
| Styling | Tailwind CSS v4 (@theme) + cva + tailwind-merge + clsx |
| Server/data state | TanStack Query (or Next server components/actions) |
| Client state | Zustand |
| Forms + validation | react-hook-form + Zod |
| Routing (non-Next) | React Router (TanStack Router if TS-first) |
| Tables | TanStack Table |
| Charts | Recharts (via shadcn charts) |
| Animation | motion (ex-Framer Motion) |
| Icons | lucide-react (+ custom typed SVG icons) |
| Toasts / cmd palette / DnD / upload | Sonner / cmdk / dnd-kit / react-dropzone + presigned uploads |
Non-negotiables
- On-token only - consume DESIGN.md tokens via Tailwind
@theme/CSS vars; no hardcoded values (claude-engineer:design-system). - TypeScript strict - full strict flags (see reference); no
anyescapes. - WCAG AA by construction - semantic HTML, keyboard nav, focus management, ARIA, reduced-motion. This is a hard gate (
claude-engineer:testing-and-quality). - Tested - Vitest + React Testing Library for components; Playwright for E2E flows.
- Monorepo placement - apps in
apps/, shared UI/config inpackages/(claude-engineer:monorepo-and-tooling).
Full detail: read references/frontend-stack.md (project structure, exact versions, tsconfig strict flags, ESLint flat config, token wiring, a11y checklist) on demand.
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.
- 5d ago First seen · 43 lines · 59 tokens per session scan A 5a4036053fa9
frontend-development is a skill published in the GitHub repository martian56/claude-engineer (2 stars, last pushed 2mo ago), licensed MIT. It adds 59 tokens to every session and 644 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 2026-08-31.
Other skills, from other repositories
fintech-frontend-engineer
Use when building React applications or components in a fintech context, implementing financial dashboards, transaction histories, payment flows, or data-heavy UIs, working with Tailwind CSS, optimising for SEO (meta tags, structured data, Core Web Vitals), improving page load performance, handling sensitive financial…
frontend-code-reviewer
Use when reviewing a frontend diff, pull request, or code snippet for correctness, React patterns, TypeScript strictness, accessibility violations, performance regressions, CSS architecture, and test quality. Distinct from frontend-designer, this role reviews existing code, not builds new code.
frontend-designer
Use when building UI components, designing layouts, writing CSS, working with React or other frontend frameworks, improving accessibility, optimizing web performance, or any task involving the visual and interactive layer of a web application.
build-recipes
Build the landing from the approved DESIGN.md and design plan on the fixed stack (Next.js + Tailwind + GSAP + Lenis, optional R3F). Use when craft/elevate invoke it after the design-plan gate, or standalone to rebuild a section. Never use before a design plan is approved.
svg-mastery
Expert knowledge for working with SVG (Scalable Vector Graphics) — optimization, embedding, animation, accessibility, responsive scaling, React integration, filters, and programmatic creation. Use when the user asks to "optimize SVG", "clean up SVG", "reduce SVG file size", "embed SVG in HTML", "inline SVG vs img…
css-architecture
Project-level CSS architecture for React/Vite websites — Tailwind CSS configuration with design tokens, shadcn/ui theming, CSS custom properties, and responsive strategy. Tailwind-first approach. Use when setting up CSS for a new React/Vite project, mapping a styleguide to Tailwind config, configuring shadcn/ui theme…