web-performance-lab

Automates testing, debugging, and optimization of the Back/Forward Cache (BfCache) for a web page. It programmatically replicates the Chrome DevTools Application panel's "Test back/forward cache" feature and extracts actionable blockers using the `notRestoredReasons` API.

Guides debugging and optimizing Cumulative Layout Shift (CLS) using Chrome DevTools MCP tools. Use this skill whenever the user asks about CLS performance, measuring visual stability, or wants to understand why their page's main content is shifting while it renders. To provide a good user experience, a site must maintain a CLS score of **0.1 or less**.

Use this guide to improve next-page load performance (including LCP) by instructing the browser to prefetch or prerender likely upcoming page views before the user explicitly navigates to them.