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 skills add christopherlouet/claude-base --skill qa-perfgit clone --depth 1 https://github.com/christopherlouet/claude-baseWrote 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/skills/christopherlouet/claude-base/qa-perf)<a href="https://agentmods.dev/skills/christopherlouet/claude-base/qa-perf"><img src="https://agentmods.dev/badge/skills/christopherlouet/claude-base/qa-perf/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/christopherlouet/claude-base/qa-perf"><img src="https://agentmods.dev/badge/skills/christopherlouet/claude-base/qa-perf.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00024 | $0.00859 |
| Opus 5 | $0.00012 | $0.00430 |
| Sonnet 5 | $0.00005 | $0.00172 |
| Haiku 4.5 | $0.00002 | $0.00086 |
Grade A, and why
qa-perf 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 58 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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-practicesskill (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 beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 6d ago First seen · 58 lines · 24 tokens per session scan A 39b683f3f2ca
qa-perf is a skill published in the GitHub repository christopherlouet/claude-base (5 stars, last pushed yesterday), licensed MIT. It adds 24 tokens to every session and 859 once invoked, about $0.0001 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 2026-09-03.
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