Individual skill

debug-optimize-lcp

Guides debugging and optimizing Largest Contentful Paint (LCP) using Chrome DevTools MCP tools. Use this skill whenever the user asks about LCP performance, slow page loads, Core Web Vitals optimization, or wants to understand why their page's main content takes too long to appear. Also use when the user mentions "largest contentful paint", "page load speed", "CWV", or wants to improve how fast their hero image or main content renders.

Google/antigravity/skills/debug-optimize-lcp/SKILL.md

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Last checked: Nov 10, 2026

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Repository stars (not skill ratings): 71,199
Repository last updated: Nov 10, 2026
License: CC0-1.0

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SKILL.mdcore · 6,608 bytes
references/elements-and-size.mddoc · 1,326 bytes
references/lcp-breakdown.mddoc · 2,525 bytes
references/lcp-snippets.mddoc · 2,436 bytes
references/optimization-strategies.mddoc · 2,154 bytes

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## What is LCP and why it matters

Largest Contentful Paint (LCP) measures how quickly a page's main content becomes visible. It's the time from navigation start until the largest image or text block renders in the viewport.

- **Good**: 2.5 seconds or less
- **Needs improvement**: 2.5–4.0 seconds
- **Poor**: greater than 4.0 seconds

LCP is a Core Web Vital that directly affects user experience and search ranking. On 73% of mobile pages, the LCP element is an image.

## LCP Subparts Breakdown

Every page's LCP breaks down into four sequential subparts with no gaps or overlaps. Understanding which subpart is the bottleneck is the key to effective optimization.