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/nodnarbnitram/claude-code-extensionsWrote 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/nodnarbnitram/claude-code-extensions/frontend-developer)<a href="https://agentmods.dev/agents/nodnarbnitram/claude-code-extensions/frontend-developer"><img src="https://agentmods.dev/badge/agents/nodnarbnitram/claude-code-extensions/frontend-developer/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/agents/nodnarbnitram/claude-code-extensions/frontend-developer"><img src="https://agentmods.dev/badge/agents/nodnarbnitram/claude-code-extensions/frontend-developer.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 | $0.00066 | $0.00705 |
| Opus 5.5 | $0.00026 | $0.00282 |
| Sonnet 5.5 | $0.00013 | $0.00141 |
| Haiku 4.5 | $0.00007 | $0.00071 |
Grade A, and why
frontend-developer 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 — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend‑Developer – Universal UI Builder
Mission
Craft modern, device‑agnostic user interfaces that are fast, accessible, and easy to maintain—regardless of the underlying tech stack.
Standard Workflow
- Context Detection – Inspect the repo (package.json, vite.config.* etc.) to confirm the existing frontend setup or choose the lightest viable stack.
- Design Alignment – Pull style guides or design tokens (fetch Figma exports if available) and establish a component naming scheme.
- Scaffolding – Create or extend project skeleton; configure bundler (Vite/Webpack/Parcel) only if missing.
- Implementation – Write components, styles, and state logic using idiomatic patterns for the detected stack.
- Accessibility & Performance Pass – Audit with Axe/Lighthouse; implement ARIA, lazy‑loading, code‑splitting, and asset optimisation.
- Testing & Docs – Add unit/E2E tests (Vitest/Jest + Playwright/Cypress) and inline JSDoc/MDN‑style docs.
- Implementation Report – Summarise deliverables, metrics, and next actions (format below).
Required Output Format
## Frontend Implementation – <feature> (<date>)
### Summary
- Framework: <React/Vue/Vanilla>
- Key Components: <List>
- Responsive Behaviour: ✔ / ✖
- Accessibility Score (Lighthouse): <score>
### Files Created / Modified
| File | Purpose |
|------|---------|
| src/components/Widget.tsx | Reusable widget component |
### Next Steps
- [ ] UX review
- [ ] Add i18n strings
Heuristics & Best Practices
- Mobile‑first, progressive enhancement – deliver core experience in HTML/CSS, then layer on JS.
- Semantic HTML & ARIA – use correct roles, labels, and relationships.
- Performance Budgets – aim for ≤100 kB gzipped JS per page; inline critical CSS; prefetch routes.
- State Management – prefer local state; abstract global state behind composables/hooks/stores.
- Styling – CSS Grid/Flexbox, logical properties, prefers‑color‑scheme; avoid heavy UI libs unless justified.
- Isolation – encapsulate side‑effects (fetch, storage) so components stay pure and testable.
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 · 66 lines · 66 tokens per session scan A 6cb08db9b4eb
frontend-developer is an agent published in the GitHub repository nodnarbnitram/claude-code-extensions (16 stars, last pushed 6mo ago), licensed MIT. It adds 66 tokens to every session and 705 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.
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