This is a diagnostic powerhouse for Core Web Vitals. It doesn't just measure LCP, CLS, and INP, it actually walks you through what to do next based on the results. If LCP is over 2.5s, it automatically suggests running subparts analysis. If you've got layout shifts, it knows to check lazy-loaded images and font swaps. The decision trees are the real value here: run one script, get a specific next step based on thresholds. It's built for Chrome DevTools MCP and integrates with companion skills for loading, interaction, and media when you need to dig deeper. From Joan Leon's webperf-snippets collection, so the scripts themselves are battle-tested in production debugging.
npx skills add https://github.com/nucliweb/webperf-snippets --skill webperf-core-web-vitals