# Canon SEO > Use when auditing or implementing technical SEO — semantic HTML, meta tags, structured data, canonical URLs, sitemap, robots.txt, page speed as a ranking factor, and accessible content. Trigger when the user mentions SEO, search engine, meta tags, structured data, sitemap, or crawlability. - Skill: `dragoon0x/canon-seo` (Agent Skill) - Install (CLI): `npx skillmds@latest add dragoon0x/canon-seo` - Raw SKILL.md: https://api.skillmd.com/api/skills/dragoon0x/canon-seo/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Marketing & Growth - Author: dragoon0x (https://skillmd.com/u/dragoon0x) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/dragoon0x/canon-seo --- # 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. - `

` once per page, matching the page topic. - Heading hierarchy (h1 → h2 → h3) reflects content structure. - `
`, `
`, `
`, `
` help crawlers understand page layout. - `` for links (not `
`). - `` describes the image for image search. ## Essential meta tags ```html Page Title — Site Name ``` - ``: 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) ```html <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). ## Anti-patterns | Anti-pattern | Why it fails | |---|---| | Same `<title>` on every page | Search engines can't distinguish pages | | No `<meta description>` | Search engine generates one (often badly) | | Keyword stuffing | Penalized by modern search engines | | Client-rendered content without SSR/SSG | Crawlers may not execute JS | | No canonical URL | Duplicate content across www/non-www, http/https | | Blocking CSS/JS in robots.txt | Crawlers can't render the page | ## Audit checklist - [ ] Unique `<title>` per page, 50–60 characters - [ ] Unique `<meta description>` per page, 120–155 characters - [ ] `<link rel="canonical">` on every page - [ ] One `<h1>` per page matching the topic - [ ] Heading hierarchy is correct - [ ] Images have descriptive `alt` text - [ ] Structured data (JSON-LD) for content types - [ ] `sitemap.xml` submitted to search consoles - [ ] `robots.txt` allows crawling of public pages - [ ] Core Web Vitals in "Good" range ## Sources - Google Search Central · SEO starter guide - Schema.org · structured data types - `canon-performance` for Core Web Vitals - `canon-accessibility` for semantic HTML