performance-audit-websites

performance-audit-websites is a skill for Codex from TheGoat395/Codex-Skills. It costs 16 tokens per session (325 once invoked), scanned A, original, MIT.

A website performance audit guide covering how quickly pages load, respond to input, and remain visually stable. It includes checks such as Core Web Vitals and Lighthouse, which are common measures of browser performance.

In plain words
What is it for?
Use it to review desktop and mobile performance, page bundles, images and video, third-party scripts, hydration, animations, and production readiness.
Why use it?
It helps identify slow assets, heavy scripts, inefficient animations, delayed fonts, and other problems that can make a website feel slow or unreliable.

Skill for Codex

Written for Codex: agents/openai.yaml present. Also seen: $skill-name invocation.

Good fit Use it to review desktop and mobile performance, page bundles, images and video, third-party scripts, hydration, animations, and production readiness.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/thegoat395/codex-skills/performance-audit-websites
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 TheGoat395/Codex-Skills --skill performance-audit-websites
Clone the repo
git clone --depth 1 https://github.com/TheGoat395/Codex-Skills

Made for: 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.

agentmods badge for performance-audit-websites

README.md
[![agentmods](https://agentmods.dev/badge/skills/thegoat395/codex-skills/performance-audit-websites/github.svg)](https://agentmods.dev/skills/thegoat395/codex-skills/performance-audit-websites)
Your own site
<a href="https://agentmods.dev/skills/thegoat395/codex-skills/performance-audit-websites"><img src="https://agentmods.dev/badge/skills/thegoat395/codex-skills/performance-audit-websites/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.

agentmods 80×15 button for performance-audit-websites

Your own site · 80×15
<a href="https://agentmods.dev/skills/thegoat395/codex-skills/performance-audit-websites"><img src="https://agentmods.dev/badge/skills/thegoat395/codex-skills/performance-audit-websites.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 325 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
  • NVIDIA SkillSpector pass 7 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00016 $0.00325
Opus 5 $0.00008 $0.00162
Sonnet 5 $0.00003 $0.00065
Haiku 4.5 $0.00002 $0.00032

Measured 4d ago against content hash 7b510962f24f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

performance-audit-websites 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.

skills/performance-audit-websites/SKILL.md · 25 lines

What it actually says

Performance Audit Websites

Use this skill to keep premium sites fast enough that visual ambition does not punish users. Measure first and optimize the dominant constraint; do not apply framework folklore as proof.

Own measured diagnosis and implementation. Route pre-build numeric budgets, acceptance thresholds, and visual-richness policy to $performance-budget-lab.

Workflow

  1. Inspect the affected surface, relevant project scripts, target URL and available inspection tooling; reuse existing context.
  2. Read Performance Audit Websites Guide before claiming the site is ready. For React or Next.js implementation work, also read React and Next.js performance.
  3. Run the narrowest meaningful checks for the risk: visual, mobile, accessibility, performance, forms, media, SEO, analytics, deployment, or handoff.
  4. Fix issues when they are in scope; otherwise record exact evidence and remaining risk.
  5. Summarize commands, URLs, screenshots/checks, changed files, and what was not tested.

Separate field data, controlled lab data, source inspection, and inference. A Lighthouse score from one machine is not a field-performance guarantee; an optimized source pattern is not a measured user improvement.

Scoped execution

Apply the shared web contract once when execution crosses phases; reuse it if already read. Load only the specialist guidance relevant to the requested surface and deliverable.

Files

What ships with it

3 files 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.

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.

  1. 4d ago Changed · -3 lines · -44 tokens per session 7b510962f24f
  2. 11d ago First seen · 28 lines · 60 tokens per session scan A 21d029b267c6

Subscribe to this mod's changes

performance-audit-websites is a skill published in the GitHub repository TheGoat395/Codex-Skills (122 stars, last pushed yesterday), licensed MIT. It adds 16 tokens to every session and 325 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 2026-08-30.

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