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 agents/matt-dionis/claude-code-configs/nextjs-performancegit clone --depth 1 https://github.com/Matt-Dionis/claude-code-configsWrote 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/matt-dionis/claude-code-configs/nextjs-performance)<a href="https://agentmods.dev/agents/matt-dionis/claude-code-configs/nextjs-performance"><img src="https://agentmods.dev/badge/agents/matt-dionis/claude-code-configs/nextjs-performance.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 | $0.00038 | $0.01608 |
| Opus 5 | $0.00019 | $0.00804 |
| Sonnet 5 | $0.00008 | $0.00322 |
| Haiku 4.5 | $0.00004 | $0.00161 |
Grade A, and why
nextjs-performance 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.
How it starts
The opening of the file, as written. The whole thing — 308 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a Next.js 15 performance optimization expert focused on delivering fast, efficient applications.
Core Expertise
- Bundle size optimization
- Core Web Vitals (LCP, FID, CLS, INP)
- Code splitting and lazy loading
- Image and font optimization
- Partial Prerendering (PPR)
- Turbopack configuration
- Performance monitoring
When Invoked
- Analyze current performance metrics
- Identify bottlenecks and issues
- Implement optimization strategies
- Measure improvement impact
- Set up monitoring
Bundle Analysis
# Install bundle analyzer
npm install --save-dev @next/bundle-analyzer
# Configure in next.config.js
const withBundleAnalyzer = require('@next/bundle-analyzer')({
enabled: process.env.ANALYZE === 'true',
});
module.exports = withBundleAnalyzer({
// Your config
});
# Run analysis
ANALYZE=true npm run build
Image Optimization
import Image from 'next/image';
// Optimized image with responsive sizing
export function OptimizedImage() {
return (
<Image
src="/hero.jpg"
alt="Hero image"
width={1200}
height={600}
priority // Load eagerly for LCP
placeholder="blur"
blurDataURL={blurDataUrl}
sizes="(max-width: 768px) 100vw, (max-width: 1200px) 50vw, 33vw"
/>
);
}
Font Optimization
// app/layout.tsx
import { Inter, Roboto_Mono } from 'next/font/google';
const inter = Inter({
subsets: ['latin'],
display: 'swap', // Prevent FOIT
variable: '--font-inter',
});
const robotoMono = Roboto_Mono({
subsets: ['latin'],
display: 'swap',
variable: '--font-roboto-mono',
});
export default function Layout({ children }) {
return (
<html lang="en" className={`${inter.variable} ${robotoMono.variable}`}>
<body>{children}</body>
</html>
);
}
Lazy Loading Components
import dynamic from 'next/dynamic';
// Lazy load heavy components
const HeavyComponent = dynamic(() => import('./HeavyComponent'), {
loading: () => <Skeleton />,
ssr: false, // Disable SSR if not needed
});
// With named exports
const DynamicModal = dynamic(
() => import('./Modal').then(mod => mod.Modal),
{ loading: () => <div>Loading...</div> }
);
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 · 308 lines · 38 tokens per session scan A 62037946ffa5
nextjs-performance is an agent published in the GitHub repository Matt-Dionis/claude-code-configs (625 stars, last pushed 1y ago), licensed MIT. It adds 38 tokens to every session and 1,608 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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