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Optimize Core Web Vitals (LCP, INP, CLS) for better page experience and search ranking.
Passed 23 of 23 test cases with the skill, and 22 of 23 without it.
1 fixed22 passed either way0 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
A test case the skill fixed. Same model, same prompt, with and without the skill.
When a user clicks a button, a single event listener performs immediate DOM updates, complex mathematical calculations, and sends analytics beacons synchronously. How should the execution timing of these tasks be split between immediate execution, visual updates, and background tasks to minimize INP?
| Checked | Without skill | With skill |
|---|---|---|
| Recommends providing immediate visual feedback in the event handler | Passed | Passed |
| Recommends deferring UI updates using requestAnimationFrame | Missed | Passed |
| Recommends scheduling analytics logging with requestIdleCallback | Passed | Passed |
The instructions your model reads when the skill loads.
Targeted optimization for the three Core Web Vitals metrics that affect Google Search ranking and user experience.
| Metric | Measures | Good | Needs work | Poor |
|---|---|---|---|---|
| LCP | Loading | ≤ 2.5s | 2.5s – 4s | > 4s |
| INP | Interactivity | ≤ 200ms | 200ms – 500ms | > 500ms |
| CLS | Visual Stability | ≤ 0.1 | 0.1 – 0.25 | > 0.25 |
Google measures at the 75th percentile — 75% of page visits must meet "Good" thresholds.
LCP measures when the largest visible content element renders. Usually this is:
<svg> element1. Slow server response (TTFB > 800ms)
Fix: CDN, caching, optimized backend, edge rendering
2. Render-blocking resources
<!-- ❌ Blocks rendering -->
<link rel="stylesheet" href="/all-styles.css">
<!-- ✅ Critical CSS inlined, rest deferred -->
<style>/* Critical above-fold CSS */</style>
<link rel="preload" href="/styles.css" as="style"
onload="this.onload=null;this.rel='stylesheet'">
test cases passed, vs 22 / 23 without
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