/seo-checker

name: seo-checker
description: Audit web pages for SEO issues in a real browser. Checks rendered meta tags, heading hierarchy, image alt text, structured data, canonical URLs, mobile rendering, and performance signals. Produces a scored report with specific findings and fixes. Read-only — inspects, doesn't modify. Requires the hanzi browser automation MCP server and Chrome extension.
category: productivity

SEO Checker

You audit web pages for SEO issues using a real browser — rendered meta tags, actual heading structure, real schema markup, mobile viewport behavior. This skill is read-only: observe and report, don't modify.

Tool Selection Rule

• Prefer existing tools first (code search, local files, `curl`). Review HTML source, meta tags, and sitemap before opening the browser.
• Use Hanzi for Phase 2–5 — always open the browser for these phases even if Phase 1 found all static data. Do not substitute curl or WebFetch for browser phases.

Before Starting

Call `browser_status` to verify the extension is reachable. If unavailable, tell the user to install from: https://chromewebstore.google.com/detail/hanzi-browse/iklpkemlmbhemkiojndpbhoakgikpmcd

What You Need

1. **URL** — page or site to audit 2. **Scope** — single page, specific section, or full site (default: single page) 3. **Focus** — any specific SEO concerns (e.g., "we're not showing up in rich results", "mobile traffic dropped")

Audit Phases

Phase 1 — Source Review (before browser)

Check what you can without a browser:

• **Robots.txt**: Fetch `<domain>/robots.txt` — check for accidental `Disallow: /` or blocked important paths. Note: some sites serve different robots.txt to different user agents (UA sniffing). If the curl result looks suspicious or overly restrictive, verify with `browser_start` to see what a real browser receives.
• **Sitemap**: Fetch `<domain>/sitemap.xml` — verify it exists and includes the target URL
• **HTML source**: If accessible, review raw `<head>` for meta tags, canonical, hreflang
• **Codebase** (if source available): Scan for hardcoded noindex, missing meta tag templates, SEO component patterns

Summarize findings before opening the browser.

Phase 2 — Meta & Head Tags (browser)

Use `browser_start` to open the page and inspect the rendered DOM. JavaScript-rendered SPAs may have different meta tags than the raw HTML source.

• **Title tag**: Exists, 50-60 characters, unique, descriptive (not "Home" or "Untitled")
• **Meta description**: Exists, 150-160 characters, includes target keywords, compelling for CTR
• **Canonical URL**: Present, points to the correct URL (not a duplicate or wrong domain)
• **Robots meta**: Check for unintentional `noindex`, `nofollow`, or `none` directives
• **Open Graph tags**: `og:title`, `og:description`, `og:image`, `og:url` — all present and correct
• **Twitter Card tags**: `twitter:card`, `twitter:title`, `twitter:description`, `twitter:image`
• **Viewport meta**: `<meta name="viewport" content="width=device-width, initial-scale=1">` present
• **Charset & lang**: `<meta charset="utf-8">` and `<html lang="...">` set correctly

Screenshot the page after loading.

Phase 3 — Content Structure (browser)

• **H1 tag**: Exactly one per page, descriptive, contains primary keyword
• **Heading hierarchy**: H1 → H2 → H3 — no skipped levels (e.g., H1 → H3 with no H2)
• **Image alt text**: All meaningful images have descriptive alt text; decorative images use `alt=""`
• **Internal links**: Key pages are linked, anchor text is descriptive (not "click here")
• **Broken links**: Check for obvious 404s or dead links on the page

Phase 4 — Structured Data (browser)

• **JSON-LD / Microdata**: Check `<script type="application/ld+json">` blocks in the rendered DOM
• **Schema types**: Verify appropriate types are used (Article, Product, LocalBusiness, BreadcrumbList, FAQ, etc.)
• **Required properties**: Each schema type has required fields — check they're populated (e.g., Article needs `headline`, `datePublished`, `author`)
• **Validation**: Flag malformed JSON-LD or schemas with empty/placeholder values

Phase 5 — Mobile & Performance (browser)

Render the page at a mobile viewport (375×812, iPhone-sized):

• **Mobile layout**: No horizontal scrolling, text readable without zooming, tap targets at least 48×48px
• **Content parity**: Mobile version has the same key content as desktop (Google uses mobile-first indexing)
• **Image optimization**: Check for oversized images (e.g., 2000px wide image in a 375px container), missing `loading="lazy"` on below-fold images
• **CLS indicators**: Elements that visibly shift during load (ads, images without dimensions, dynamically injected content)
• **Core Web Vitals**: Use `javascript_tool` to extract real navigation timing from the Performance API:

const nav = performance.getEntriesByType('navigation')[0];
const paint = performance.getEntriesByType('paint');
({
  ttfb: nav.responseStart - nav.requestStart,
  domContentLoaded: nav.domContentLoadedEventEnd - nav.startTime,
  load: nav.loadEventEnd - nav.startTime,
  fcp: paint.find(e => e.name === 'first-contentful-paint')?.startTime,
});

Screenshot at mobile viewport.

Scoring

Rate each category on a 0-10 scale:

| Category | What's checked | |----------|---------------| | **Meta Tags** | Title, description, canonical, robots, OG, Twitter cards | | **Content Structure** | H1, heading hierarchy, image alt text, internal links | | **Structured Data** | JSON-LD presence, correct types, required properties | | **Mobile** | Responsive layout, content parity, tap targets | | **Performance Signals** | Image sizes, lazy loading, CLS indicators | | **Internationalisation** | hreflang alternates, lang attribute, multilingual implementation |

**Overall score** = average of the 6 category scores (out of 10).

• **9-10**: Excellent — production-ready SEO
• **7-8**: Good — minor improvements needed
• **5-6**: Needs work — several issues aff