layout-shift-qa

Detects and diagnoses layout shifts using Chrome's PerformanceObserver.

6|Updated Jan 14, 2026
One-click install
npx skills add https://github.com/markacianfrani/armor --skill layout-shift-qa
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: layout-shift-qa
Source: https://github.com/markacianfrani/armor/tree/main/skills/layout-shift-qa
Command: npx skills add https://github.com/markacianfrani/armor --skill layout-shift-qa

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This skill solves the problem of invisible or hard-to-reproduce layout shifts (CLS) that degrade user experience by providing a repeatable, instrumented QA loop for web interfaces.

Core Features & Use Cases

  • Automated Instrumentation: Injects a PerformanceObserver into the browser to capture layout-shift entries, including node identifiers and bounding-rect deltas.
  • Diagnostic Taxonomy: Maps observed shifts to four common root causes: state-driven content swaps, layout-affecting animations, async content arrival, and viewport-dependent reflows.
  • A/B Validation: Provides a rigorous workflow to verify fixes by deliberately re-introducing bugs to confirm the instrumentation is active and accurate.

Quick Start

Use the layout-shift-qa skill to instrument the current page and identify the root cause of any layout shifts occurring during the search interaction.

Frequently Asked Questions about layout-shift-qa

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I detect Cumulative Layout Shift (CLS) issues during web QA testing?▼

To detect Cumulative Layout Shift (CLS) issues during QA, this skill injects a PerformanceObserver into Chrome to capture layout-shift entries, recording node identifiers and bounding-rect deltas for precise diagnosis.

What causes layout shifts and UI jank in web applications?▼

Layout shifts and UI jank are caused by state-driven content swaps, layout-affecting animations, async content arrival, and viewport-dependent reflows, which this skill maps observed shifts against for root cause analysis.

How do I automate Core Web Vitals optimization checks using Chrome DevTools?▼

You automate Core Web Vitals optimization by integrating with chrome-devtools MCP tools to drive user interactions, allowing the PerformanceObserver to evaluate performance metrics and capture layout shifts in real-time.

Can I validate layout shift fixes by deliberately re-introducing bugs?▼

Yes, you can validate layout shift fixes through A/B validation, which deliberately re-introduces bugs to confirm the PerformanceObserver instrumentation is active, accurate, and capturing the expected UI jank.

Does this layout shift instrumentation work with browser-based QA workflows?▼

Yes, this layout shift instrumentation is specifically designed for browser-based QA workflows, targeting invisible or hard-to-reproduce content jumping and Core Web Vitals optimization directly within the Chrome environment.

Why does my web page content jump when async content loads?▼

Your web page content jumps when async content arrives because it triggers viewport-dependent reflows, a diagnostic category this skill identifies by mapping layout-shift entries to their underlying root causes.