Qa perf

Skill christopherlouet/claude-base/.claude/skills/qa-perf

Application performance optimization. Trigger when the user wants to improve speed, reduce latency, or optimize resources.From its SKILL.md

Install

npx -y skills add christopherlouet/claude-base --skill qa-perf

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

5 stars5 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

SKILL.md

3.1 KB, 783 tokens by cl100k_base, as published. Nobody here has run it

Performance Optimization (pointer)

Canonical thresholds, current Web Vitals (LCP/INP/CLS — note INP replaced FID in 2024), and Chrome perf-team remediation patterns are at:

addyosmani/web-quality-skills — github.com/addyosmani/web-quality-skills (MIT, 1.8k★, maintained by Addy Osmani — Chrome DevTools / Lighthouse engineering lead). Covers Core Web Vitals, perf, a11y, SEO.
web.dev/vitals — web.dev/vitals (Google's canonical Web Vitals reference)
Vercel React best practices — see vercel-react-best-practices skill (foundation-installed) for React-specific patterns

Foundation workflow (when to invoke this skill)

qa-perf is dispatched by qa-loop during the AUDIT phase, in parallel with qa-security / wcag-audit / qa-claudemd. It's a measurement workflow, not an optimisation cookbook:

Measure first: run Lighthouse / WebPageTest / DevTools Performance against a known scope (the URL, page, or endpoint from argument-hint).
Compare to canonical thresholds (see table below).
Identify the bottleneck axis: render-blocking JS? N+1 DB query? Image weight? Bundle size? Each axis has a dedicated vendor remediation guide.
Recommend with quantified impact (e.g. "lazy-loading hero image saves ~400ms LCP per Lighthouse run #3").
Re-measure after the fix — a perf change without before/after numbers is theatre.

Canonical Web Vitals thresholds (2024-2026)

Metric	Good	Needs improvement	Poor	Tool
LCP (Largest Contentful Paint)	< 2.5s	2.5–4s	> 4s	Lighthouse, web-vitals
INP (Interaction to Next Paint, replaces FID)	< 200ms	200–500ms	> 500ms	web-vitals
CLS (Cumulative Layout Shift)	< 0.1	0.1–0.25	> 0.25	Lighthouse, web-vitals
TTFB	< 200ms	200–600ms	> 600ms	DevTools Network

Foundation discipline (keep across releases)

No optimisation without measurement: profile before changing code. Guessed bottlenecks are wrong ~70% of the time.
Before/after numbers mandatory: every perf PR must include the Lighthouse delta or equivalent. Without numbers, the work is unprovable.
Cache invalidation > caching: adding a cache is easy; correctly invalidating it is the bug surface. Surface cache TTLs in code review.
N+1 is the #1 backend perf bug: when an endpoint feels slow, instrument query count before optimising anything else.

What ships with it: 1 file

2.4 KB alongside SKILL.md

examples/

lighthouse-audit.md2.4 KB