hreflang-international

hreflang-international is a skill for Claude Code from nowork-studio/notfair-plugin. It costs 242 tokens per session (1,399 once invoked), scanned A, original, MIT.

An international SEO audit for checking hreflang signals, which tell search engines which language or regional version of a page to show.

In plain words
What is it for?
It checks return links, language and region codes, default versions, self-references, canonical links, and consistency across representative multilingual pages.
Why use it?
It finds inconsistencies that can cause the wrong language or regional page to appear in search results.

Skill for Claude Code

Written for Claude Code: argument-hint in frontmatter.

Part of the notfair plugin — 52 skills, 1 MCP server shipped together

Good fit It checks return links, language and region codes, default versions, self-references, canonical links, and consistency across representative multilingual pages.

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Install with agentmods
npx agentmods add skills/nowork-studio/notfair-plugin/hreflang-international
About the project

NotFair Plugin is a collection of open-source SEO, generative-engine-optimization, and marketing workflows that AI agents can follow. It helps agents audit websites, analyze search and advertising data, plan campaigns, and make reviewable marketing changes; the catalogue entries are its skills, instructions, MCP connection, and plugin.

nowork-studio/notfair-plugin · 3,703 stars · on GitHub · notfair.co

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 nowork-studio/notfair-plugin --skill hreflang-international
Clone the repo
git clone --depth 1 https://github.com/nowork-studio/notfair-plugin

Made for: Claude Code.

Or install notfair, the plugin that ships this one along with the rest of its 52 skills, 1 MCP server.

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 hreflang-international

README.md
[![agentmods](https://agentmods.dev/badge/skills/nowork-studio/notfair-plugin/hreflang-international/github.svg)](https://agentmods.dev/skills/nowork-studio/notfair-plugin/hreflang-international)
Your own site
<a href="https://agentmods.dev/skills/nowork-studio/notfair-plugin/hreflang-international"><img src="https://agentmods.dev/badge/skills/nowork-studio/notfair-plugin/hreflang-international/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 hreflang-international

Your own site · 80×15
<a href="https://agentmods.dev/skills/nowork-studio/notfair-plugin/hreflang-international"><img src="https://agentmods.dev/badge/skills/nowork-studio/notfair-plugin/hreflang-international.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 242 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,399 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00242 $0.01399
Opus 5 $0.00121 $0.00700
Sonnet 5 $0.00048 $0.00280
Haiku 4.5 $0.00024 $0.00140

Measured 12d ago against content hash 8364f78eb44f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

hreflang-international 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.

seo/hreflang-international/SKILL.md · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

International & Hreflang SEO Audit

You are a senior international-SEO engineer. Your job is to verify that a multilingual / multi-region site sends Google clean, consistent language and region signals — and to pinpoint exactly which hreflang errors are causing the wrong page to surface for the wrong audience.

Hreflang is unforgiving: a single broken return tag silently drops the whole cluster's hreflang benefit. This skill is mechanical and precise.

Credit: capability inspired by the open-source claude-seo project (MIT, Agrici Daniel). Implementation is original to NotFair.


Step 0 — Scope

Collect:

  • Site URL ($SITE_URL).
  • Language/region versions that exist (e.g. th, en, en-US, th-TH). Infer from the site if the user doesn't list them.
  • How versions are served — subdirectory (/en/), subdomain (en.), ccTLD (.co.th), or URL parameter.

Pick a small set of representative URL clusters (the same page in each language, e.g. homepage + one product page) to inspect in depth. Hreflang errors repeat across templates, so 2–3 clusters reveal systemic problems.


Phase 0 — Preflight & data

Read and follow ../shared/preamble.md for script discovery and GSC auth.

If GSC is connected, check the Performance → search results report filtered by country to see whether the wrong language version ranks in a given market — that confirms a live hreflang/targeting problem, not just a theoretical one.


Phase 1 — Discover the hreflang signals

For each representative URL, find hreflang annotations in all three possible locations and record where they live:

  1. HTML <head><link rel="alternate" hreflang="..." href="..." />
  2. HTTP headersLink: header (common for PDFs / non-HTML).
  3. XML sitemap<xhtml:link rel="alternate" hreflang="..."> entries.

A site should use one method consistently. Using two that disagree is a common bug — flag it.


Phase 2 — Validate every annotation

Read the full file on GitHub · 130 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 · 130 lines · 242 tokens per session scan A 8364f78eb44f

Subscribe to this mod's changes

hreflang-international is a skill published in the GitHub repository nowork-studio/notfair-plugin (3,703 stars, last pushed yesterday), licensed MIT. It adds 242 tokens to every session and 1,399 once invoked, about $0.0012 per session on Opus 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 2026-08-30.

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