Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/adobecom/da-express-milo/lighthouse-performance-troubleshootinggit clone --depth 1 https://github.com/adobecom/da-express-miloWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/adobecom/da-express-milo/lighthouse-performance-troubleshooting)<a href="https://agentmods.dev/rules/adobecom/da-express-milo/lighthouse-performance-troubleshooting"><img src="https://agentmods.dev/badge/rules/adobecom/da-express-milo/lighthouse-performance-troubleshooting.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.02166 | $0.02166 |
| Opus 5 | $0.01083 | $0.01083 |
| Sonnet 5 | $0.00433 | $0.00433 |
| Haiku 4.5 | $0.00217 | $0.00217 |
Grade A, and why
lighthouse-performance-troubleshooting scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
1 near-identical copy found in the catalogue:
- lighthouse-performance-troubleshooting — 100% identical, 0 lines differ
How it starts
The opening of the file, as written. The whole thing — 304 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Lighthouse Performance Troubleshooting Guide
APPLY: EVERY QUERY - LIGHTHOUSE SCORE OPTIMIZATION
Target Performance Scores
Based on Express-Milo architecture requirements:
- Performance: 90+ (Target: 97-100)
- Accessibility: 100
- Best Practices: 100
- SEO: 92+
Critical Performance Issues & Solutions
Issue 1: LCP > 3 seconds (Score drops from 100 to 86)
Root Cause Analysis:
- Large content elements not optimized for LCP detection
- Render-blocking resources in critical path
- Poor content hierarchy in first section
REQUIRED Solutions:
/* ✅ First section must dominate viewport */
.section:first-child {
min-height: 100vh;
background-image: url('high-entropy-image.jpg');
background-size: cover;
}
/* ✅ Ensure LCP element is largest contentful element */
.section:first-child h1 {
font-size: clamp(2rem, 5vw, 4rem);
margin: 2rem 0;
}
/* ✅ Make first section image larger than second section */
.section:first-child img {
width: 100%;
max-width: 800px; /* Larger than second section */
}
.section:nth-child(2) img {
max-width: 600px; /* Smaller than first section */
}
Content Strategy Fix:
// ✅ Auto-block to ensure proper LCP structure
function buildAutoBlocks(main) {
const firstSection = main.querySelector('.section');
const h1 = firstSection?.querySelector('h1');
const firstImage = firstSection?.querySelector('img');
if (firstSection && (!firstImage || hasLowEntropy(firstImage))) {
// Add high-entropy background for LCP detection
firstSection.style.backgroundImage = 'url("/express/assets/hero-texture.jpg")';
firstSection.classList.add('hero-section');
}
}
Issue 2: Largest Contentful Paint Optimization
Problem: LCP element not in first section (common cause of 86 vs 100 score)
Diagnostic Steps:
- Check LCP element location: Use Chrome DevTools → Performance → Web Vitals
- Verify first section dominance: Ensure first section fills viewport
- Image size hierarchy: First section image > second section image
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 4d ago First seen · 304 lines · 2,166 tokens per session scan A e0aa4c1279bd
lighthouse-performance-troubleshooting is a cursor rule published in the GitHub repository adobecom/da-express-milo (6 stars, last pushed today), licensed Apache-2.0. It adds 2,166 tokens to every session, about $0.0108 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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