From kostja94-marketing-skills-5
Guides optimization of Core Web Vitals (LCP, INP, CLS) for improved page experience and search rankings. Covers diagnostics, thresholds, and fixes for loading, responsiveness, and visual stability.
npx claudepluginhub joshuarweaver/cascade-data-analytics --plugin kostja94-marketing-skills-5This skill uses the workspace's default tool permissions.
Guides optimization of Core Web Vitals (CWV)—Google's user experience metrics that affect search ranking. CWV are confirmed ranking factors for mobile and desktop.
Conducts multi-round deep research on GitHub repos via API and web searches, generating markdown reports with executive summaries, timelines, metrics, and Mermaid diagrams.
Dynamically discovers and combines enabled skills into cohesive, unexpected delightful experiences like interactive HTML or themed artifacts. Activates on 'surprise me', inspiration, or boredom cues.
Generates images from structured JSON prompts via Python script execution. Supports reference images and aspect ratios for characters, scenes, products, visuals.
Guides optimization of Core Web Vitals (CWV)—Google's user experience metrics that affect search ranking. CWV are confirmed ranking factors for mobile and desktop.
When invoking: On first use, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On subsequent use or when the user asks to skip, go directly to the main output.
| Metric | Target | Good | Needs Improvement | Poor |
|---|---|---|---|---|
| LCP | ≤2.5s | ≤2.5s | 2.5–4.0s | >4.0s |
| INP | ≤200ms | ≤200ms | 200–500ms | >500ms |
| CLS | <0.1 | ≤0.1 | 0.1–0.25 | >0.25 |
Source: Google Page Experience
Check for project context first: If .claude/project-context.md or .cursor/project-context.md exists, read it for site URL.
Identify:
LCP measures the time until the largest content element (image, video, or text block) is visible.
| Cause | Fix |
|---|---|
| Slow server response | Reduce TTFB; use CDN; optimize server |
| Render-blocking resources | Defer non-critical CSS/JS; inline critical CSS |
| Large images | WebP/AVIF; compress; width/height to prevent CLS; see image-optimization |
| Client-side rendering | SSR/SSG for above-fold content; see rendering-strategies |
| Third-party scripts | Load async; defer non-critical |
LCP candidates: Hero image, large text block, video poster. Ensure above-fold images use loading="eager" (default); never lazy-load LCP.
INP measures responsiveness—time from user interaction to next paint. Replaced FID in March 2024.
| Cause | Fix |
|---|---|
| Long-running JS | Break tasks >50ms; use requestIdleCallback; Web Workers |
| Heavy event handlers | Debounce/throttle; defer non-critical work |
| Main thread blocking | Reduce third-party scripts; defer non-critical JS |
| Layout thrashing | Batch DOM reads/writes; avoid forced reflows |
CLS measures unexpected layout shifts.
| Cause | Fix |
|---|---|
| Images without dimensions | Always set width and height attributes |
| Dynamic content | Reserve space for ads, embeds; use min-height |
| Web fonts | font-display: optional or swap; preload critical fonts |
| Animations | Use transform instead of top/left/width |
Reserve space: For images, ads, embeds—define dimensions before load. Avoid inserting content above existing content without reserved space.
| Tool | Use |
|---|---|
| GSC | Core Web Vitals report; URL grouping; field data |
| PageSpeed Insights | Lab + field data; mobile + desktop |
| Chrome DevTools | Performance panel; LCP element; layout shift overlay |