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/vudovn/ag-kit/nextjs-react-expertnpx skills add vudovn/ag-kit --skill nextjs-react-expertgit clone --depth 1 https://github.com/vudovn/ag-kitWrote 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/vudovn/ag-kit/nextjs-react-expert)<a href="https://agentmods.dev/skills/vudovn/ag-kit/nextjs-react-expert"><img src="https://agentmods.dev/badge/skills/vudovn/ag-kit/nextjs-react-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 | $0.00048 | $0.02445 |
| Opus 5 | $0.00024 | $0.01222 |
| Sonnet 5 | $0.00010 | $0.00489 |
| Haiku 4.5 | $0.00005 | $0.00245 |
Grade A, and why
nextjs-react-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 4d 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- nextjs-react-expert — 91% identical, 78 lines differ
- nextjs-react-expert — 91% identical, 78 lines differ
How it starts
The opening of the file, as written. The whole thing — 294 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Next.js & React Performance Expert
From Vercel Engineering - 58 optimization rules prioritized by impact, plus Next.js 16 Cache Components Philosophy: Eliminate waterfalls first, optimize bundles second, then micro-optimize.
🎯 Selective Reading Rule (MANDATORY)
Read ONLY sections relevant to your task! Check the content map below and load what you need.
🔴 For performance reviews: Start with CRITICAL sections (1-2), then move to HIGH/MEDIUM.
📑 Content Map
| File | Impact | Rules | When to Read |
|---|---|---|---|
1-async-eliminating-waterfalls.md |
🔴 CRITICAL | 6 rules | Slow page loads, sequential API calls, data fetching waterfalls |
2-bundle-bundle-size-optimization.md |
🔴 CRITICAL | 5 rules | Large bundle size, slow Time to Interactive, First Load issues |
3-server-server-side-performance.md |
🟠 HIGH | 7 rules | Slow SSR, API route optimization, server-side waterfalls |
4-client-client-side-data-fetching.md |
🟡 MEDIUM-HIGH | 4 rules | Client data management, SWR patterns, deduplication |
5-rerender-re-render-optimization.md |
🟡 MEDIUM | 12 rules | Excessive re-renders, React performance, memoization |
6-rendering-rendering-performance.md |
🟡 MEDIUM | 9 rules | Rendering bottlenecks, virtualization, image optimization |
7-js-javascript-performance.md |
⚪ LOW-MEDIUM | 12 rules | Micro-optimizations, caching, loop performance |
8-advanced-advanced-patterns.md |
🔵 VARIABLE | 3 rules | Advanced React patterns, useLatest, init-once |
9-cache-components.md |
🔴 CRITICAL | 4 sections | Next.js 16+ Only: use cache, cacheLife, PPR, cacheTag |
What ships with it
11 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.
- 1-async-eliminating-waterfalls.md 8.6 KB
- 2-bundle-bundle-size-optimization.md 6.1 KB
- 3-server-server-side-performance.md 13 KB
- 4-client-client-side-data-fetching.md 6.7 KB
- 5-rerender-re-render-optimization.md 15 KB
- 6-rendering-rendering-performance.md 10 KB
- 7-js-javascript-performance.md 17 KB
- 8-advanced-advanced-patterns.md 3.6 KB
- 9-cache-components.md 2.8 KB
- scripts/convert_rules.py 6.5 KB runs code
- scripts/react_performance_checker.py 11 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.
- 4d ago First seen · 294 lines · 48 tokens per session scan A 1db0736663af
nextjs-react-expert is a skill published in the GitHub repository vudovn/ag-kit (8,168 stars, last pushed 4d ago), licensed MIT. It adds 48 tokens to every session and 2,445 once invoked, about $0.0002 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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