30x-seo-hreflang

30x-seo-hreflang is a skill for Claude Code from norahe0304-art/30x-seo. It costs 74 tokens per session (2,104 once invoked), scanned A, a copy of seo-hreflang, MIT.

A tool for checking hreflang tags, which tell search engines which language or regional version of a page to show. It can validate or generate these tags in HTML, HTTP headers, and XML sitemaps.

In plain words
What is it for?
Use it to audit international websites, check language and country codes, verify that language versions link back to one another, and create hreflang implementations.
Why use it?
It helps find broken links between translated or regional pages, invalid language codes, missing fallback pages, and other errors that can prevent search engines from using the language signals correctly.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions CLAUDE.md.

Good fit Use it to audit international websites, check language and country codes, verify that language versions link back to one another, and create hreflang implementations.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/norahe0304-art/30x-seo/30x-seo-hreflang
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 norahe0304-art/30x-seo --skill 30x-seo-hreflang
Clone the repo
git clone --depth 1 https://github.com/norahe0304-art/30x-seo

Made for: Claude Code.

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 30x-seo-hreflang

README.md
[![agentmods](https://agentmods.dev/badge/skills/norahe0304-art/30x-seo/30x-seo-hreflang/github.svg)](https://agentmods.dev/skills/norahe0304-art/30x-seo/30x-seo-hreflang)
Your own site
<a href="https://agentmods.dev/skills/norahe0304-art/30x-seo/30x-seo-hreflang"><img src="https://agentmods.dev/badge/skills/norahe0304-art/30x-seo/30x-seo-hreflang/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.

agentmods 80×15 button for 30x-seo-hreflang

Your own site · 80×15
<a href="https://agentmods.dev/skills/norahe0304-art/30x-seo/30x-seo-hreflang"><img src="https://agentmods.dev/badge/skills/norahe0304-art/30x-seo/30x-seo-hreflang.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 74 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,104 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 83% 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 5.1 $0.00074 $0.02104
Opus 5 $0.00037 $0.01052
Sonnet 5 $0.00015 $0.00421
Haiku 4.5 $0.00007 $0.00210

Measured 12d ago against content hash 79663a241053, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

30x-seo-hreflang 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 12d 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.

Origin

This is a copy

83% identical to seo-hreflang — 122 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.

skills/30x-seo-hreflang/SKILL.md · 190 lines

How it starts

The opening of the file, as written. The whole thing — 190 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Hreflang & International SEO

Validate existing hreflang implementations or generate correct hreflang tags for multi-language and multi-region sites. Supports HTML, HTTP header, and XML sitemap implementations.

Validation Checks

1. Self-Referencing Tags

  • Every page must include an hreflang tag pointing to itself
  • The self-referencing URL must exactly match the page's canonical URL
  • Missing self-referencing tags cause Google to ignore the entire hreflang set

2. Return Tags

  • If page A links to page B with hreflang, page B must link back to page A
  • Every hreflang relationship must be bidirectional (A→B and B→A)
  • Missing return tags invalidate the hreflang signal for both pages
  • Check all language versions reference each other (full mesh)

3. x-default Tag

  • Required: designates the fallback page for unmatched languages/regions
  • Typically points to the language selector page or English version
  • Only one x-default per set of alternates
  • Must also have return tags from all other language versions

4. Language Code Validation

  • Must use ISO 639-1 two-letter codes (e.g., en, fr, de, ja)
  • Common errors:
    • eng instead of en (ISO 639-2, not valid for hreflang)
    • jp instead of ja (incorrect code for Japanese)
    • zh without region qualifier (ambiguous — use zh-Hans or zh-Hant)

5. Region Code Validation

  • Optional region qualifier uses ISO 3166-1 Alpha-2 (e.g., en-US, en-GB, pt-BR)
  • Format: language-REGION (lowercase language, uppercase region)
  • Common errors:
    • en-uk instead of en-GB (UK is not a valid ISO 3166-1 code)
    • es-LA (Latin America is not a country — use specific countries)
    • Region without language prefix

6. Canonical URL Alignment

  • Hreflang tags must only appear on canonical URLs
  • If a page has rel=canonical pointing elsewhere, hreflang on that page is ignored
  • The canonical URL and hreflang URL must match exactly (including trailing slashes)
  • Non-canonical pages should not be in any hreflang set

Read the full file on GitHub · 190 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. 12d ago First seen · 190 lines · 74 tokens per session scan A 79663a241053

Subscribe to this mod's changes

30x-seo-hreflang is a skill published in the GitHub repository norahe0304-art/30x-seo (51 stars, last pushed 6mo ago), licensed MIT. It adds 74 tokens to every session and 2,104 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 83% identical to seo-hreflang, differing in 122 lines, and is treated as a copy.

Related

Other skills, from other repositories

local-falcon

Expert guidance on AI Visibility and Local SEO from Local Falcon, the pioneer of geo-grid rank tracking. Provides deep knowledge on optimizing for AI search platforms (ChatGPT, Gemini, AI Mode, AI Overviews, Grok), local pack rankings, Google Business Profile optimization, and actionable strategies for agencies…

local-falcon/mcp · 84 tokens

geo-audit

Full website GEO+SEO audit with parallel subagent delegation. Orchestrates a comprehensive Generative Engine Optimization audit across AI citability, platform analysis, technical infrastructure, content quality, and schema markup. Produces a composite GEO Score (0-100) with prioritized action plan.

techhorizonlabs/thl-open · 60 tokens

geo

GEO-first SEO analysis tool. Optimizes websites for AI-powered search engines (ChatGPT, Claude, Perplexity, Gemini, Google AI Overviews) while maintaining traditional SEO foundations. Performs full GEO audits, citability scoring, AI crawler analysis, llms.txt generation, brand mention scanning, platform-specific…

techhorizonlabs/thl-open · 139 tokens

geo-brand-mentions

Brand mention and authority scanner for AI visibility. Analyzes brand presence across platforms that AI models rely on for entity recognition and citation decisions. Produces a Brand Authority Score (0-100) with platform-specific recommendations.

techhorizonlabs/thl-open · 49 tokens

geo-llmstxt

Analyzes and generates llms.txt files -- the emerging standard for helping AI systems understand website structure and content. Can validate existing llms.txt files or generate new ones from scratch by crawling the site.

techhorizonlabs/thl-open · 46 tokens

found-by-ai

Measure whether AI engines actually recommend a business when buyers ask. Runs the free live scan at areyoufoundbyai.com (no auth, 60s), reads the verdict and the rivals AI names instead, hands back the fix plan, and wires monitored sites into a fix-and-re-measure loop over MCP.

techhorizonlabs/thl-open · 67 tokens