Borrowing it
Nothing to install: this file belongs to diillson/chatcli. 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/diillson/chatcli/main/.agent/skills/nextjs-react-expert/SKILL.mdgit clone --depth 1 https://github.com/diillson/chatcliWrote 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/diillson/chatcli/nextjs-react-expert)<a href="https://agentmods.dev/skills/diillson/chatcli/nextjs-react-expert"><img src="https://agentmods.dev/badge/skills/diillson/chatcli/nextjs-react-expert/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/diillson/chatcli/nextjs-react-expert"><img src="https://agentmods.dev/badge/skills/diillson/chatcli/nextjs-react-expert.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 | $0.00048 | $0.02226 |
| Opus 5.5 | $0.00019 | $0.00890 |
| Sonnet 5.5 | $0.00010 | $0.00445 |
| Haiku 4.5 | $0.00005 | $0.00223 |
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 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.
This is a copy
91% identical to nextjs-react-expert — 78 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 268 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 - 57 optimization rules prioritized by impact 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 | 5 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 |
Total: 57 rules across 8 categories
🚀 Quick Decision Tree
What's your performance issue?
🐌 Slow page loads / Long Time to Interactive
→ Read Section 1: Eliminating Waterfalls
→ Read Section 2: Bundle Size Optimization
📦 Large bundle size (> 200KB)
→ Read Section 2: Bundle Size Optimization
→ Check: Dynamic imports, barrel imports, tree-shaking
🖥️ Slow Server-Side Rendering
→ Read Section 3: Server-Side Performance
→ Check: Parallel data fetching, streaming
🔄 Too many re-renders / UI lag
→ Read Section 5: Re-render Optimization
→ Check: React.memo, useMemo, useCallback
🎨 Rendering performance issues
→ Read Section 6: Rendering Performance
→ Check: Virtualization, layout thrashing
🌐 Client-side data fetching problems
→ Read Section 4: Client-Side Data Fetching
→ Check: SWR deduplication, localStorage
✨ Need advanced patterns
→ Read Section 8: Advanced Patterns
What ships with it
10 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 7.6 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
- scripts/convert_rules.py 6.5 KB runs code
- scripts/react_performance_checker.py 9.8 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 · 268 lines · 48 tokens per session scan A e3efd7e71d2d
nextjs-react-expert is a skill published in the GitHub repository diillson/chatcli (93 stars, last pushed today), licensed Apache-2.0. It adds 48 tokens to every session and 2,226 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 91% identical to nextjs-react-expert, differing in 78 lines, and is treated as a copy.
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