A guide to technical SEO, which helps search engines find and understand web pages. It covers page structure, metadata, links, images, duplicate URLs, sitemaps, and crawl rules.

Use it to audit or implement headings, semantic HTML, title and description tags, canonical URLs, structured data, sitemaps, robots.txt, and page-speed improvements.

It removes common technical problems that can make pages hard for search engines to index or interpret. It also connects accessible page structure with better search visibility.

canon-seo — Skill for Claude Code and Codex by Dragoon0x/canon

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 Dragoon0x/canon --skill canon-seo

Clone the repo

git clone --depth 1 https://github.com/Dragoon0x/canon

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/dragoon0x/canon/canon-seo/github.svg)](https://agentmods.dev/skills/dragoon0x/canon/canon-seo)

Your own site

<a href="https://agentmods.dev/skills/dragoon0x/canon/canon-seo"><img src="https://agentmods.dev/badge/skills/dragoon0x/canon/canon-seo/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/dragoon0x/canon/canon-seo"><img src="https://agentmods.dev/badge/skills/dragoon0x/canon/canon-seo.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 876 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.

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	$0.00062	$0.00876
Opus 5.5	$0.00025	$0.00350
Sonnet 5.5	$0.00012	$0.00175
Haiku 4.5	$0.00006	$0.00088

Measured 2mo ago against content hash 97ae5ffb87e8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

canon-seo 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.

source/skills/canon-seo/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CANON · SEO

Technical SEO is about making content findable and understandable by search engines. Not tricks — structure.

Semantic HTML is SEO

Search engines understand semantic HTML natively. Every rule in canon-accessibility that improves screen reader experience also improves SEO.

<h1> once per page, matching the page topic.
Heading hierarchy (h1 → h2 → h3) reflects content structure.
<nav>, <main>, <article>, <aside> help crawlers understand page layout.
<a href> for links (not <div onClick>).
<img alt> describes the image for image search.

Essential meta tags

<head>
  <title>Page Title — Site Name</title>
  <meta name="description" content="Concise summary under 155 characters.">
  <link rel="canonical" href="https://example.com/page">
  <meta name="robots" content="index, follow">
</head>

<title>: 50–60 characters. Unique per page. Primary keyword near the front.
<meta description>: 120–155 characters. Compelling summary. Unique per page.
<link rel="canonical">: prevents duplicate content penalties.
<meta robots>: index, follow is default. noindex for admin pages.

Structured data (JSON-LD)

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Article",
  "headline": "Page Title",
  "author": { "@type": "Person", "name": "Author" },
  "datePublished": "2026-04-18"
}
</script>

Use for: articles, products, FAQs, breadcrumbs, organizations, events. Google uses structured data for rich results (stars, prices, FAQ dropdowns).

Page speed = ranking factor

Core Web Vitals are a Google ranking signal. See canon-performance for targets:

LCP ≤ 2.5s
INP ≤ 200ms
CLS ≤ 0.1

Crawlability

robots.txt: allow crawlers access to important pages, block admin/API routes.
sitemap.xml: list all public pages with <lastmod> dates.
Internal linking: every important page reachable within 3 clicks from the homepage.
No orphan pages (pages with no internal links pointing to them).

Read the full file on GitHub · 96 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 · 96 lines · 62 tokens per session scan A 97ae5ffb87e8

Subscribe to this mod's changes

canon-seo is a skill published in the GitHub repository Dragoon0x/canon (6 stars, last pushed 6mo ago), licensed MIT. It adds 62 tokens to every session and 876 once invoked, about $0.0002 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 2026-09-03.

Claude Code Marketing and SEO accessibility ai-agent ai-coding audit codex

canon-seo next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
canon-seoDragoon0x/canon	Skill	6	6mo ago	MIT	A	62	Claude Code, Codex
accessibilitydiegosouzapw/awesome-omni-skills	Skill	170	4mo ago	MIT	C	119	Claude Code, Codex
accessibilityericrisco/rsc-harness	Skill	503	2d ago	MIT	A	86	Claude Code, Codex
Website AuditPramodDutta/qaskills	Skill	245	4d ago	MIT	A	33	Claude Code, Codex
huawei-cloud-cts-trace-managementhuaweicloud/huaweicloud-devkit	Skill	70	yesterday	Apache-2.0	A	249	Claude Code
accessibility-auditoyi77/1ai-skills	Skill	17	yesterday	MIT	A	29	Claude Code
a11y-auditgreglas75/zuvo	Skill	7	3d ago	MIT	A	147	Claude Code