A focused review of how quickly pages load and respond, using measures such as Core Web Vitals, which are Google’s page-experience metrics.

It helps investigate LCP, CLS, INP, FCP, and TTFB, review resource sizes, and recommend page-speed improvements.

It connects slow scores to likely causes, such as server delays, large resources, layout movement, or scripts that delay interaction.

audit-speed — Skill for Claude Code and Codex by calm-north

Install

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.

Any agent

npx skills add calm-north/seojuice-skills --skill audit-speed

Clone the repo

git clone --depth 1 https://github.com/calm-north/seojuice-skills

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/calm-north/seojuice-skills/audit-speed/github.svg)](https://agentmods.dev/skills/calm-north/seojuice-skills/audit-speed)

Your own site

<a href="https://agentmods.dev/skills/calm-north/seojuice-skills/audit-speed"><img src="https://agentmods.dev/badge/skills/calm-north/seojuice-skills/audit-speed/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/calm-north/seojuice-skills/audit-speed"><img src="https://agentmods.dev/badge/skills/calm-north/seojuice-skills/audit-speed.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 70 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,605 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

Socket pass 16 Sept 2026
Snyk pass 16 Sept 2026

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

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	$0.00070	$0.01605
Opus 5.5	$0.00028	$0.00642
Sonnet 5.5	$0.00014	$0.00321
Haiku 4.5	$0.00007	$0.00161

Measured 2mo ago against content hash f8102a2b5c34, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

audit-speed 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 2mo 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.

skills/audit-speed/SKILL.md · 159 lines

How it starts

The opening of the file, as written. The whole thing — 159 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Audit Speed

Deep Core Web Vitals audit with root-cause analysis trees and resource optimization recommendations.

Core Web Vitals Thresholds

Metric	Good	Needs Improvement	Poor
LCP (Largest Contentful Paint)	< 2.5s	2.5s - 4.0s	> 4.0s
CLS (Cumulative Layout Shift)	< 0.1	0.1 - 0.25	> 0.25
INP (Interaction to Next Paint)	< 200ms	200ms - 500ms	> 500ms
FCP (First Contentful Paint)	< 1.8s	1.8s - 3.0s	> 3.0s
TTFB (Time to First Byte)	< 800ms	800ms - 1800ms	> 1800ms

Before You Start

Gather this context:

Which pages? Homepage, key landing pages, or specific slow pages.
Current scores. If the user has Lighthouse or PageSpeed Insights data, start there.
Tech stack. CMS, framework, hosting — this determines which optimizations are available.
Known constraints. Third-party scripts they can't remove, design requirements that limit optimization.

If no data is available, suggest running Google PageSpeed Insights on the key URLs.

LCP Root-Cause Tree

LCP measures when the largest visible element finishes rendering. Diagnose:

Is TTFB slow (> 800ms)?

→ Server response time issue
Check: hosting quality, CDN configuration, database queries, server-side rendering time
Fix: upgrade hosting, add CDN, optimize server-side code, enable caching

Is the LCP element an image?

→ Image optimization issue
Check: image format (use WebP/AVIF), image size (serve responsive sizes), lazy loading on LCP image (should NOT be lazy loaded)
Fix: convert to modern formats, add width/height attributes, use fetchpriority="high" on LCP image, preload the LCP image

Is the LCP element text?

→ Font loading issue
Check: custom fonts blocking render, font file size, font-display strategy
Fix: use font-display: swap or optional, preload critical fonts, subset fonts to used characters

Is render-blocking CSS/JS delaying the LCP?

Check: large CSS files in <head>, synchronous JS before content
Fix: inline critical CSS, defer non-critical CSS, async/defer JS

Read the full file on GitHub · 159 lines

Changes

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.

2mo ago First seen · 159 lines · 70 tokens per session scan A f8102a2b5c34

Subscribe to this mod's changes

audit-speed is a skill published in the GitHub repository calm-north/seojuice-skills (21 stars, last pushed 8mo ago), licensed MIT. It adds 70 tokens to every session and 1,605 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-30.

Analytics and metrics Frontend marketing seo

audit-speed next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
audit-speedcalm-north/seojuice-skills	Skill	21	8mo ago	MIT	A	70	Claude Code, Codex
content-amplifieraaron-he-zhu/aaron-marketing-skills	Skill	3.1k	yesterday	Apache-2.0	A	202	Claude Code
cold-outbound-sequenceraaron-he-zhu/aaron-marketing-skills	Skill	3.1k	yesterday	Apache-2.0	A	172	Claude Code
inbox-placement-monitoraaron-he-zhu/aaron-marketing-skills	Skill	3.1k	yesterday	Apache-2.0	A	166	Claude Code
newsletter-monetization-planneraaron-he-zhu/aaron-marketing-skills	Skill	3.1k	yesterday	Apache-2.0	A	139	Claude Code
audience-mapperaaron-he-zhu/aaron-marketing-skills	Skill	3.1k	yesterday	Apache-2.0	A	156	Claude Code
pricing-packaging-planneraaron-he-zhu/aaron-marketing-skills	Skill	3.1k	yesterday	Apache-2.0	A	166	Claude Code