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 skills add roedyrustam/vibes-plug --skill performance-web-vitalsgit clone --depth 1 https://github.com/roedyrustam/vibes-plugWrote 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/roedyrustam/vibes-plug/performance-web-vitals)<a href="https://agentmods.dev/skills/roedyrustam/vibes-plug/performance-web-vitals"><img src="https://agentmods.dev/badge/skills/roedyrustam/vibes-plug/performance-web-vitals.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00079 | $0.02935 |
| Opus 5 | $0.00039 | $0.01468 |
| Sonnet 5 | $0.00016 | $0.00587 |
| Haiku 4.5 | $0.00008 | $0.00294 |
Grade A, and why
performance-web-vitals 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 — 339 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Web Performance & Core Web Vitals Expert
English
Orchestration & Integration
Connects and orchestrates with relevant domain skills like brainstorming, zero-to-prod-orchestrator, and project-context-mapper to ensure cohesive execution.
Description
Expert guide for measuring, diagnosing, and optimizing web application performance with a focus on Core Web Vitals (LCP, INP, CLS), JavaScript bundle optimization, image and font loading strategies, rendering performance, and achieving high Lighthouse scores. Covers Next.js 15, React 19, and modern browser APIs.
Trigger Conditions
- Improving Lighthouse performance score below 90.
- Diagnosing poor LCP, INP, or CLS metrics.
- Reducing JavaScript bundle size or eliminating render-blocking resources.
- Optimizing image loading, lazy loading, or font delivery.
- Implementing React performance patterns (memo, useDeferredValue, Suspense).
- Setting up Real User Monitoring (RUM) for Core Web Vitals.
- Optimizing server response times (TTFB).
Core Web Vitals Targets (2024+)
| Metric | Good | Needs Improvement | Poor | Measures |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | ≤ 2.5s | 2.5–4.0s | > 4.0s | Loading performance |
| INP (Interaction to Next Paint) | ≤ 200ms | 200–500ms | > 500ms | Interactivity (replaced FID) |
| CLS (Cumulative Layout Shift) | ≤ 0.1 | 0.1–0.25 | > 0.25 | Visual stability |
| FCP (First Contentful Paint) | ≤ 1.8s | 1.8–3.0s | > 3.0s | Perceived loading |
| TTFB (Time to First Byte) | ≤ 800ms | 800–1800ms | > 1800ms | Server responsiveness |
LCP Optimization Strategies
1. Identify and Optimize the LCP Element
// Measure LCP with web-vitals library
import { onLCP, onINP, onCLS } from 'web-vitals';
onLCP((metric) => {
console.log('LCP:', metric.value, 'element:', metric.attribution.lcpEntry?.element);
// Send to analytics
sendToAnalytics({ name: metric.name, value: metric.value });
});
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 · 339 lines · 79 tokens per session scan A f7d318f0fd2b
performance-web-vitals is a skill published in the GitHub repository roedyrustam/vibes-plug (49 stars, last pushed today), licensed MIT. It adds 79 tokens to every session and 2,935 once invoked, about $0.0004 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 2026-09-03.
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