HomeCasa Prioritize Core Web Vitals fixes (LCP, INP, CLS) by template and impact
Interpret your Core Web Vitals data, separate field from lab results, pinpoint causes per page template and get an improvement plan ranked by SEO impact and effort. Designed for ChatGPT, Claude, Gemini and Microsoft Copilot. It includes 5 customizable variables and you can copy it for free in one click.
Advanced · Text · Pending editorial review
Prompt
Act as a web performance and technical SEO specialist who prioritizes Core Web Vitals work by its real impact on users and the business.
Context:
- Site and stack (CMS, framework, hosting, CDN): {{site_stack}}
- Field data (Search Console Core Web Vitals report or CrUX, by URL group and device): {{field_data}}
- Lab data (PageSpeed Insights or Lighthouse for representative URLs, with failing audits): {{lab_data}}
- Page templates and their business weight: {{templates}}
- Available resources: {{resources}}
Deliverables:
1. Diagnosis per template: which metric fails (LCP, INP or CLS) at the 75th percentile, on mobile or desktop, and whether lab data matches field data. Explain any mismatch.
2. Likely causes for each failure, tied to concrete evidence in the data (LCP element, third-party scripts, long tasks, images without dimensions, web fonts, client-side rendering).
3. A list of fixes with expected impact (high, medium, low), effort, affected template and owner (content, development, infrastructure).
4. A three-phase plan: quick wins, structural improvements and architecture decisions, sized to {{resources}}.
5. Concrete technical instructions for the top 5 fixes, adapted to {{site_stack}}.
6. How to measure: what to expect in lab data right away and why field data takes a few weeks to reflect changes.
Constraints:
- Do not invent metric values. If data is missing, write [FILL IN] and tell me how to get it.
- Be honest about SEO weight: Core Web Vitals are part of page experience signals and do not make up for less relevant content. Do not promise ranking gains.
- Prioritize the templates with the most traffic and revenue, not the overall Lighthouse score.
- If the data is not enough to identify the cause, tell me which trace or extra report you need.
Format: diagnosis table, prioritized fix table, phased plan and technical instructions.How to use it
Export the Core Web Vitals report from Search Console and run one representative URL per template through PageSpeed Insights. Paste both, noting which templates drive the most revenue. Start with the quick wins and re-measure after 4 weeks.
Usage example
Site: WooCommerce on a commercial theme · Field: 1,800 product URLs with LCP "Needs improvement" on mobile · Lab: 900 KB hero image with no preload · Resources: 3 dev days.
Sample output
Diagnosis by template (mobile, 75th percentile)
| Template | Failing metric | Field data | Matches lab data | Revenue weight |
|---|---|---|---|---|
| Product page | LCP | 3.4 s (needs improvement) | Yes: 900 KB hero image, no preload | 70% |
| Category page | INP | 380 ms (poor) | Yes: 600 ms long task in the filter | 25% |
| Blog | — | [FILL IN] | [FILL IN] | 5% |
Prioritized fixes
| Fix | Impact | Effort | Template | Owner |
|---|---|---|---|---|
| Compress the hero image (WebP/AVIF) and serve responsive sizes | High | Low | Product | Content |
Preload the LCP image and remove loading="lazy" from it | High | Low | Product | Development |
| Split the filter script and defer non-urgent work | High | Medium | Category | Development |
| Audit the 14 third-party scripts and delay non-essential ones | Medium | Medium | All | Marketing + dev |
Phase 1: quick wins (month 1)
- Add
fetchpriority="high"to the main product image in the theme template. - Turn on image conversion in Cloudflare or one plugin, not both.
- …
Measuring: lab results change immediately; Search Console field data uses a 28-day window, so expect several weeks. Core Web Vitals are part of page experience signals and do not guarantee ranking gains…
Key facts
- Category
- Marketing & SEO · Technical SEO
- Output type
- Text
- Level
- Advanced
- Designed for
- ChatGPT, Claude, Gemini and Microsoft Copilot
- Verified in
- Pending editorial verification
- Variables
- Site and stack, Field data, Lab data, Templates and business weight and Available resources
- Language
- English
- Price
- Free, no sign-up
- Updated
- Nov 7, 2026
Frequently asked questions
What is the difference between field and lab data?
Field data comes from real Chrome users over the last 28 days and is what Google uses. Lab data is a simulation that is useful for debugging but may not match.
Has INP replaced FID?
Yes. Since March 2024, Interaction to Next Paint is the official responsiveness metric in Core Web Vitals. A good value is 200 ms or less at the 75th percentile.
Will better Core Web Vitals guarantee higher rankings?
No. It is one signal among many; it helps most when you compete with pages of similar relevance, and it also tends to improve conversion.
What is this prompt for?
Interpret your Core Web Vitals data, separate field from lab results, pinpoint causes per page template and get an improvement plan ranked by SEO impact and effort.
Which AI tools does it work with?
It is designed for ChatGPT, Claude, Gemini and Microsoft Copilot. We have not verified it in these tools yet, so results may vary between them.
How do I customize the prompt?
Click “Customize” and fill in the variables (Site and stack, Field data, Lab data, Templates and business weight and Available resources). The text updates instantly and you can then copy it in one click. Values are stored only in your browser.
Do I need experience to use it?
It is advanced: it is meant for people with experience in the topic who can evaluate and adjust the result.
Is this prompt free?
Yes. Every HomeCasa Prompts prompt is free, with no sign-up or subscription. You can also use them in professional projects.
Can I trust the AI output?
Treat it as a high-quality draft: always check data, figures and important claims before publishing or making decisions.