Agent Skills

web-performance-audit

Conduct comprehensive web performance audits. Measure page speed, identify bottlenecks, and recommend optimizations to improve user experience and SEO.

Install

npx skills add https://github.com/aj-geddes/useful-ai-prompts --skill web-performance-audit
SKILL.md

Web Performance Audit

Table of Contents

Overview

Web performance audits measure load times, identify bottlenecks, and guide optimization efforts to create faster, better user experiences.

When to Use

  • Regular performance monitoring
  • After major changes
  • User complaints about slowness
  • SEO optimization
  • Mobile optimization
  • Performance baseline setting

Quick Start

Minimal working example:

Core Web Vitals (Google):

Largest Contentful Paint (LCP):
  Measure: Time to load largest visible element
  Good: <2.5 seconds
  Poor: >4 seconds
  Impacts: User perception of speed

First Input Delay (FID):
  Measure: Time from user input to response
  Good: <100 milliseconds
  Poor: >300 milliseconds
  Impacts: Responsiveness

Cumulative Layout Shift (CLS):
  Measure: Visual stability (unexpected layout shifts)
  Good: <0.1
  Poor: >0.25
  Impacts: User frustration

---

Additional Metrics:

First Contentful Paint (FCP):
// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide Contents
Performance Metrics Performance Metrics
Performance Analysis Process Performance Analysis Process
Optimization Strategies Optimization Strategies
Monitoring & Continuous Improvement Monitoring & Continuous Improvement

Best Practices

✅ DO

  • Measure regularly (not just once)
  • Use field data (real users) + lab data
  • Focus on Core Web Vitals
  • Set realistic targets
  • Prioritize by impact
  • Monitor continuously
  • Setup performance budgets
  • Test on slow networks
  • Include mobile in testing
  • Document improvements

❌ DON'T

  • Ignore field data
  • Focus on one metric only
  • Set impossible targets
  • Optimize without measurement
  • Forget about images
  • Ignore JavaScript costs
  • Skip mobile performance
  • Over-optimize prematurely
  • Forget about monitoring
  • Expect improvements without effort

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