SEO On-Page: Metadata (Other Meta Tags)

Guides optimization of meta tags beyond title, description, Open Graph, and Twitter Cards. Covers hreflang, robots, viewport, charset, and metadata completeness.

When invoking: On first use, if helpful, open with 1–2 sentences on what this skill covers and why it matters, then provide the main output. On subsequent use or when the user asks to skip, go directly to the main output.

Scope (On-Page SEO)

Hreflang: Language/region targeting for multilingual sites
Meta robots: index/noindex, follow/nofollow (page-level)
Viewport: Mobile responsiveness
Charset: Character encoding
Metadata completeness: All pages have title + meta description (see title-tag, meta-description)

Initial Assessment

Check for project context first: If .claude/project-context.md or .cursor/project-context.md exists, read it for language/locale and indexing goals.

Identify:

Multi-language: zh, en, x-default if applicable
Indexing: Full index, noindex for specific pages
Tech stack: Next.js, HTML, etc.

hreflang (Multi-language)

Three non-negotiables: (1) Self-referencing tags (each page links to itself), (2) Symmetric annotations (every version lists ALL others), (3) Valid ISO 639-1 or language-region codes (en, en-US, zh-CN).

Implementation methods: HTML <link> in head, XML sitemap (xhtml:link), or HTTP headers. For SPAs/JS-rendered pages, use sitemap-based hreflang as backup. See rendering-strategies for SSR/SSG/CSR.

Canonical alignment: Canonical URL must match the same regional version hreflang refers to. Misalignment causes Google to ignore hreflang.

x-default: Fallback for users whose language/location doesn't match any version. Point to default locale or language-selector page.

Next.js (App Router)

export const metadata = {
  alternates: {
    languages: {
      'en-US': '/en/page',
      'zh-CN': '/zh/page',
      'x-default': '/en/page',
    },
  },
};

HTML (generic)

<link rel="alternate" hreflang="en" href="https://example.com/en/page" />
<link rel="alternate" hreflang="zh" href="https://example.com/zh/page" />
<link rel="alternate" hreflang="x-default" href="https://example.com/en/page" />

Common Mistakes (Avoid)

Missing reciprocal references between language versions.
Canonical tag conflicting with hreflang.
Relying solely on machine translation without localization (see translation).
Ignoring mobile—hreflang must appear on both desktop and mobile.
Forgetting to update hreflang when page structure changes.

Meta Robots (Page-level)

Page-level control for indexing and link following. See indexing for which page types typically need noindex.

Directive	Effect
`noindex`	Exclude page from search results
`nofollow`	Do not pass link equity through links on the page; does NOT prevent indexing
`noindex,follow`	Exclude from SERP; allow crawlers to follow links (most common for thank-you, signup, legal)
`noindex,nofollow`	Exclude + block link flow (login, staging, test pages)

Crawl vs index vs link equity: robots.txt = crawl control; noindex = index control; nofollow = link equity only. See robots-txt, indexing.

<meta name="robots" content="noindex, follow">

Next.js: metadata.robots = { index: false, follow: true }. Default is index: true, follow: true.

Viewport

<meta name="viewport" content="width=device-width, initial-scale=1">

Required for mobile-friendly pages; affects Core Web Vitals and mobile search. For full mobile-first indexing and mobile usability requirements, see mobile-friendly.

Charset

<meta charset="UTF-8">

Place in <head>; first child of <head> recommended.

Output Format

hreflang setup if multi-language
Meta robots if noindex needed
Viewport / charset if missing

Related Skills

title-tag, meta-description: Title and meta description
open-graph, twitter-cards: Social sharing; link previews
canonical-tag: Canonical + hreflang for multi-language
indexing: noindex page-type list; noindex vs nofollow
robots-txt: Crawl vs index; robots.txt vs noindex
mobile-friendly: Mobile-first indexing; viewport required
rendering-strategies: SSR, SSG, CSR; SPAs need sitemap-based hreflang

page-metadata