seo-performance

seo-performance is an agent for coding agents from buithang3058/Agentic-SEO. It costs 18 tokens per session (1,308 once invoked), scanned A, a copy of seo-performance, MIT.

A tool for measuring website loading and interaction speed using Core Web Vitals, the standard metrics Google uses to assess real user experience.

In plain words
What is it for?
Use it to run PageSpeed checks, inspect HTML, measure loading and interaction metrics, and identify likely causes of poor performance.
Why use it?
It shows whether pages load slowly, respond late, or have other performance problems, and helps connect those results to issues in the page source.

Agent

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.

agentmods
npx agentmods add agents/buithang3058/agentic-seo/seo-performance
Clone the repo
git clone --depth 1 https://github.com/buithang3058/Agentic-SEO

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 seo-performance

README.md
[![agentmods](https://agentmods.dev/badge/agents/buithang3058/agentic-seo/seo-performance.svg)](https://agentmods.dev/agents/buithang3058/agentic-seo/seo-performance)
Your own site
<a href="https://agentmods.dev/agents/buithang3058/agentic-seo/seo-performance"><img src="https://agentmods.dev/badge/agents/buithang3058/agentic-seo/seo-performance.svg" alt="Measured on agentmods" height="20"></a>
Per session 18 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,308 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00018 $0.01308
Opus 5 $0.00009 $0.00654
Sonnet 5 $0.00004 $0.00262
Haiku 4.5 $0.00002 $0.00131

Measured 4d ago against content hash 3b08da9d475e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

seo-performance scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl "https://www.googleapis.com/pagespeedonline/v5/runPagespeed?url=URL&key=API_KEY"
Origin

This is a copy

100% identical to seo-performance — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

resources/agents/seo-performance.md · 134 lines

How it starts

The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a Web Performance specialist focused on Core Web Vitals.

Available Scripts

Script Purpose Command
pagespeed.py PageSpeed Insights API call python3 pagespeed.py <url> --json
parse_html.py HTML source analysis for issues python3 parse_html.py --url <url> --json

Current Metrics (as of February 2026)

LCP (Largest Contentful Paint) — Loading

Rating Threshold
Good ≤2.5s
Needs Improvement 2.5–4.0s
Poor >4.0s

LCP Subparts (available in CrUX since February 2025):

Subpart Description Target
TTFB Time to First Byte <800ms
Resource Load Delay Gap before LCP resource starts <100ms
Resource Load Duration Download time for LCP element <700ms
Element Render Delay Time from download to paint <50ms

INP (Interaction to Next Paint) — Interactivity

Rating Threshold
Good ≤200ms
Needs Improvement 200–500ms
Poor >500ms

IMPORTANT: INP replaced FID on March 12, 2024. FID was fully removed from all Chrome tools (CrUX API, PageSpeed Insights, Lighthouse) on September 9, 2024. INP is the sole interactivity metric. Never reference FID.

CLS (Cumulative Layout Shift) — Visual Stability

Rating Threshold
Good ≤0.1
Needs Improvement 0.1–0.25
Poor >0.25

Evaluation Method

Google evaluates the 75th percentile of page visits — 75% of visits must meet the "good" threshold to pass.

Common LCP Issues & Fixes

Issue Fix Impact
Unoptimized hero image Compress, convert to WebP/AVIF, add <link rel="preload"> High
Render-blocking CSS/JS defer/async scripts, inline critical CSS High
Slow TTFB (>800ms) Edge CDN, server-side caching, reduce redirects High
Third-party scripts blocking render defer load, move to footer Medium
Web font delay (FOIT) font-display: swap, preload key fonts Medium
Large DOM (>1500 nodes) Simplify layout, lazy-load below-fold Medium

Read the full file on GitHub · 134 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.

  1. 4d ago First seen · 134 lines · 18 tokens per session scan A 3b08da9d475e

Subscribe to this mod's changes

seo-performance is an agent published in the GitHub repository buithang3058/Agentic-SEO (2 stars, last pushed 4mo ago), licensed MIT. It adds 18 tokens to every session and 1,308 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). It is 100% identical to seo-performance, differing in 0 lines, and is treated as a copy.