Web Performance Optimization

Overview

This public intake copy packages

packages/skills-catalog/skills/(performance)/perf-web-optimization

https://github.com/tech-leads-club/agent-skills

Use it when the operator needs the upstream workflow, support files, and repository context to stay intact while the public validator and private enhancer continue their normal downstream flow.

This intake keeps the copied upstream files intact and uses

metadata.json

ORIGIN.md

Web Performance Optimization Systematic approach: Measure → Identify → Prioritize → Implement → Verify.

Imported source sections that did not map cleanly to the public headings are still preserved below or in the support files. Notable imported sections: Target Metrics, Quick Wins, Bundle Analysis, Code Splitting Patterns, Caching Headers, Measurement.

When to Use This Skill

Use this section as the trigger filter. It should make the activation boundary explicit before the operator loads files, runs commands, or opens a pull request.

• Use when the request clearly matches the imported source intent: Optimize web performance: bundle size, images, caching, lazy loading, and overall page speed. Use when site is slow, reducing bundle size, fixing layout shifts, improving Time to Interactive, or optimizing for....
• Use when the operator should preserve upstream workflow detail instead of rewriting the process from scratch.
• Use when provenance needs to stay visible in the answer, PR, or review packet.
• Use when copied upstream references, examples, or scripts materially improve the answer.
• Use when the workflow should remain reviewable in the public intake repo before the private enhancer takes over.

Operating Table

metadata.json

ORIGIN.md

references/bundle-optimization.md

references/core-web-vitals.md

## Related Skills

Workflow

This workflow is intentionally editorial and operational at the same time. It keeps the imported source useful to the operator while still satisfying the public intake standards that feed the downstream enhancer flow.

1. Confirm the user goal, the scope of the imported workflow, and whether this skill is still the right router for the task.
2. Read the overview and provenance files before loading any copied upstream support files.
3. Load only the references, examples, prompts, or scripts that materially change the outcome for the current request.
4. Execute the upstream workflow while keeping provenance and source boundaries explicit in the working notes.
5. Validate the result against the upstream expectations and the evidence you can point to in the copied files.
6. Escalate or hand off to a related skill when the work moves out of this imported workflow's center of gravity.
7. Before merge or closure, record what was used, what changed, and what the reviewer still needs to verify.

Imported Workflow Notes

Imported: Target Metrics

Examples

Example 1: Ask for the upstream workflow directly

Use @perf-web-optimization to handle <task>. Start from the copied upstream workflow, load only the files that change the outcome, and keep provenance visible in the answer.

Explanation: This is the safest starting point when the operator needs the imported workflow, but not the entire repository.

Example 2: Ask for a provenance-grounded review

Review @perf-web-optimization against metadata.json and ORIGIN.md, then explain which copied upstream files you would load first and why.

Explanation: Use this before review or troubleshooting when you need a precise, auditable explanation of origin and file selection.

Example 3: Narrow the copied support files before execution

Use @perf-web-optimization for <task>. Load only the copied references, examples, or scripts that change the outcome, and name the files explicitly before proceeding.

Explanation: This keeps the skill aligned with progressive disclosure instead of loading the whole copied package by default.

Example 4: Build a reviewer packet

Review @perf-web-optimization using the copied upstream files plus provenance, then summarize any gaps before merge.

Explanation: This is useful when the PR is waiting for human review and you want a repeatable audit packet.

Imported Usage Notes

Imported: Detailed Examples

For in-depth optimization patterns, see:

• references/core-web-vitals.md - Fixing LCP, CLS, INP issues
• references/bundle-optimization.md - Reducing JS bundle size
• references/image-optimization.md - Image formats, responsive images, sharp scripts

Best Practices

Treat the generated public skill as a reviewable packaging layer around the upstream repository. The goal is to keep provenance explicit and load only the copied source material that materially improves execution.

• Keep the imported skill grounded in the upstream repository; do not invent steps that the source material cannot support.
• Prefer the smallest useful set of support files so the workflow stays auditable and fast to review.
• Keep provenance, source commit, and imported file paths visible in notes and PR descriptions.
• Point directly at the copied upstream files that justify the workflow instead of relying on generic review boilerplate.
• Treat generated examples as scaffolding; adapt them to the concrete task before execution.
• Route to a stronger native skill when architecture, debugging, design, or security concerns become dominant.

Troubleshooting

Problem: The operator skipped the imported context and answered too generically

Symptoms: The result ignores the upstream workflow in

packages/skills-catalog/skills/(performance)/perf-web-optimization

metadata.json

ORIGIN.md

Problem: The imported workflow feels incomplete during review

Symptoms: Reviewers can see the generated

SKILL.md

Problem: The task drifted into a different specialization

Symptoms: The imported skill starts in the right place, but the work turns into debugging, architecture, design, security, or release orchestration that a native skill handles better. Solution: Use the related skills section to hand off deliberately. Keep the imported provenance visible so the next skill inherits the right context instead of starting blind.

Related Skills

• @accessibility

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @ai-cold-outreach

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @ai-pricing

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

• @ai-sdr

  - Use when the work is better handled by that native specialization after this imported skill establishes context.

Additional Resources

Use this support matrix and the linked files below as the operator packet for this imported skill. They should reflect real copied source material, not generic scaffolding.

references

references/bundle-optimization.md

examples

examples/n/a

scripts

scripts/n/a

agents

agents/n/a

assets

assets/n/a

• bundle-optimization.md
• core-web-vitals.md
• image-optimization.md
• bundle-optimization.md
• core-web-vitals.md
• image-optimization.md

Imported Reference Notes

Imported: Quick Wins

1. Images (usually biggest impact on LCP)

<!-- Hero/LCP image: eager + high priority -->
<img src="/hero.webp" alt="Hero" width="1200" height="600" loading="eager" fetchpriority="high" decoding="async" />

<!-- Below fold: lazy load -->
<img src="/product.webp" alt="Product" width="400" height="300" loading="lazy" decoding="async" />

Always set

width

height

2. Fonts (common LCP/CLS culprit)

<!-- Preconnect to font origin -->
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />

<!-- Non-blocking font load -->
<link
  rel="stylesheet"
  href="https://fonts.googleapis.com/css2?family=Inter&display=swap"
  media="print"
  onload="this.media='all'"
/>

3. Third-party Scripts (common INP killer)

<!-- Defer to user interaction -->
<script>
  function loadThirdParty() {
    // Load analytics, chat widgets, etc.
  }
  ;['scroll', 'click', 'touchstart'].forEach((e) => addEventListener(e, loadThirdParty, { once: true, passive: true }))
  setTimeout(loadThirdParty, 5000)
</script>

4. Critical CSS

Inline critical CSS in

<head>

<style>
  /* critical styles */
</style>
<link rel="preload" href="/styles.css" as="style" onload="this.rel='stylesheet'" />

Imported: Bundle Analysis

# Webpack
npx webpack-bundle-analyzer dist/stats.json

# Vite
npx vite-bundle-visualizer

# Check package size before installing
npx bundlephobia <package-name>

Common heavy packages to replace:

• moment

  (67KB) →

  date-fns

  (12KB) or

  dayjs

  (2KB)

• lodash

  (72KB) → cherry-pick imports or native methods

Imported: Code Splitting Patterns

// React lazy
const Chart = lazy(() => import('./Chart'))

// Next.js dynamic
const Admin = dynamic(() => import('./Admin'), { ssr: false })

// Vite/Rollup manual chunks
build: {
  rollupOptions: {
    output: {
      manualChunks: {
        vendor: ['react', 'react-dom']
      }
    }
  }
}

Imported: Caching Headers

# Static assets (immutable hash in filename)
Cache-Control: public, max-age=31536000, immutable

# HTML (revalidate)
Cache-Control: no-cache

# API responses
Cache-Control: private, max-age=0, must-revalidate

Imported: Measurement

For running audits, reading reports, and setting budgets, use the perf-lighthouse skill.

Imported: Checklist

Images

• Modern formats (WebP/AVIF)
• Responsive

  srcset

• width

  /

  height

  attributes

• loading="lazy"

  below fold

• fetchpriority="high"

  on LCP image

JavaScript

• Bundle < 200KB gzipped
• Code splitting by route
• Third-party scripts deferred
• No unused dependencies

CSS

• Critical CSS inlined
• Non-critical CSS deferred
• No unused CSS

Fonts

• font-display: swap

• Preconnect to font origin
• Subset if possible