From 88 to 100 PSI: Claude Code for Front-End Optimisation
A developer used Claude Code as a debugging and implementation partner to push their site's PageSpeed Insights mobile score from 88 to 100 (an article template went from 74 to 100). The post on r/ClaudeAI details the hands-on workflow — not a one-shot fix, but a series of targeted interventions.
Key Optimisations Achieved
- Responsive images + srcset: Claude identified that the mobile hero image was larger than needed, then generated responsive image variants and added
srcsetattributes. - LCP preload: Added a responsive preload for the LCP image using
<link rel="preload" as="image" imagesrcset="...">. - Forced reflow fix: Replaced a header scroll listener (which caused forced layout on scroll) with
IntersectionObserver. - Font audit: Identified which font weights were actually in use and removed unused ones.
- Build-time image dimensions: Added
widthandheightattributes to markdown images at build time to eliminate layout shifts. - Removed font preloads on article pages: Counterintuitive but effective — preloaded fonts were competing with the hero image for bandwidth on throttled mobile. Since fonts used
font-display: swap, removing preloads let the LCP image load faster.
Effective Prompting Pattern
The developer found Claude Code works best with specific diagnostic threads. Instead of vague prompts, feed it PSI findings and ask for the smallest safe patch. Example pattern: feed the PageSpeed Insights finding, ask Claude to inspect the relevant component, then request a minimal fix rather than a broad refactor.
Human Judgment Still Required
Some optimisations felt too aggressive visually — the author bumped logo quality back up while staying at 100. Below-the-fold images and styling trade-offs needed human decisions. Claude Code accelerated the iteration, but the developer still had to balance performance, accessibility, and design quality.
Full Write-Up
The author published a longer technical version with specific CWV changes and before/after numbers at goodrich.digital.
📖 Read the full source: r/ClaudeAI
👀 See Also
OpenClaw installation hurdles on Windows 11 for non-developers
A recreational tinkerer details three specific obstacles when installing OpenClaw on a $200 Mini PC running Windows 11, including PowerShell execution policies, Windows Defender blocks, and missing dependencies like Node.js and Git.
CLAUDE.md Constitution: Building a Personal AI Agent — Part II File Walkthrough
A CEO shares the annotated CLAUDE.md file — 16 sections covering identity, proactive initiative, memory, deadlines, and hard rules — built over 6 weeks for a 50-person company.
Using Claude to analyze writing patterns for better custom instructions
A Reddit user describes a method for creating more effective custom instructions by having Claude analyze 10 writing samples to identify concrete patterns like punctuation avoidance and analogy sources, rather than relying on subjective tone descriptions.
Reddit Post: Developers Need Better AI Coding Practices, Not Just Better Tools
A Reddit post argues that developers' dissatisfaction with AI coding tools stems from poor prompting practices, specifically 'raw prompting' without context or structure. The author recommends using scaffolding like CLAUDE.md and structured workflows to get production-ready code from Claude.