seo-international (M20)

SkillSearch

Audit and generate hreflang annotations for multilingual sites — check reciprocity, BCP-47 validity, self-reference, x-default, hreflang/canonical conflicts, and <html lang> agreement, and emit reciprocal hreflang link sets. Module M20 (conditional). Feeds the Search SEO score.

Available today. Use it from your connected AI after setup.

Connect ahel once, and every AI you use reads what you have installed.

Then ask your AI: use the seo-international (M20) skill

What this skill tells your AI

The instructions your AI receives, as published by hainrixz/claude-seo-ai in skills/seo-international/SKILL.md and read by ahel’s review.

hreflang tells search engines which language/region URL to serve. This module is conditional: it only runs when seo-vertical-detect flags a multilingual site (multiple lang/locale URLs, language switcher, or existing hreflang). On monolingual sites every finding is not_applicable at severity 0. Schema-type concerns defer to references/schema-tier1.md; this module owns link-level localization only.

Inputs

Work from the PageSnapshot named in your dispatch envelope: read parsed from <run_dir>/pages/<slug>.json (hreflang[], canonicals[], <html lang> in parsed) plus headers.link and the sibling pages under <run_dir>/pages/ for reciprocity; Grep pages/<slug>.html for verbatim evidence; site artifacts live in <run_dir>/site/{robots.json,sitemaps.json,discovery.json}. Deterministic findings already emitted by audit.mjs are listed in <run_dir>/findings.deterministic.json — do not re-emit those ids; add model-judged findings only. If invoked directly with a URL/path and no snapshot exists, first run node "${CLAUDE_PLUGIN_ROOT}/scripts/snapshot.mjs" <target> --out "${CLAUDE_PLUGIN_DATA}/runs" and use the printed snapshot path.

Audits

Working from the PageSnapshot (parsed_rendered when render.used is not none, else parsed). Read hreflang from <link rel="alternate" hreflang="..."> in <head> (also accept HTTP Link: headers / sitemap xhtml:link when present):

  1. Reciprocity — if page A declares an alternate B, B must declare A back. One-way hreflang is ignored by Google.
  2. BCP-47 validity — each hreflang value is a valid language (en) or language-region (en-GB, pt-BR) tag; region is ISO-3166-1 alpha-2, not a country-of-language guess (en-UK is invalid; use en-GB).
  3. Self-reference — the page lists itself in its own hreflang set.
  4. x-default — at least one hreflang="x-default" for the language-selector / fallback URL.
  5. hreflang↔canonical conflict — an hreflang URL must be self-canonical; pointing hreflang at a URL whose rel=canonical is a different page neutralizes the cluster (cross-check M2/seo-indexability).
  6. <html lang> agreement — the document lang attribute matches the locale this URL targets in its own hreflang entry.

Fixes

  • AUTO (fixable: auto): when the locale→URL map is known (supplied by the user, a sitemap, or discovered alternates), generate a complete reciprocal hreflang link set — every locale + a single x-default — as a <head> diff for fix. Additive and deterministic.
  • PROPOSED (fixable: proposed): a partial set inferred from discovered alternates that needs the user to confirm the locale map before write.
  • ADVISORY (fixable: advisory): "this looks multilingual but no locale map exists" — never written by the tool.
  • Never fabricate locales, region codes, or alternate URLs. If the map is incomplete, leave a clearly-marked TODO(locale) placeholder and ask the user.

Verification

  • Offline: node "${CLAUDE_PLUGIN_ROOT}/scripts/hreflang-check.mjs" --snapshot <pages/<slug>.json> (or --url <u> / --file <path>) — parses the alternate set from the <link> tags and the HTTP Link header (entries, header_entries), validates BCP-47 tags (invalid_bcp47), and reports has_x_default, self_referenced, duplicate_langs and the canonical-vs-hreflang conflict. Reciprocity is not in this mode: it needs --url <u> --deep [--budget 25] [--ua <preset>], which fetches each declared alternate.
  • Reciprocity requires fetching each declared alternate; when those URLs (or a sitemap tier) are unavailable, status is needs_api, never a false pass.

Findings

Findings conform to schema/finding.schema.json; axis search. On a monolingual site every id is not_applicable at severity 0. Severity policy: 5 is reserved for catastrophic, eligibility-killing facts at site/template scope; 4 major · 3 moderate · 2 minor · 1 cosmetic · 0 informational — and only an established severity-5 fail in an active category can cap a score (references/scoring-model.md).

  • M20.hreflang.missing_reciprocal — the page declares hreflang="de-DE" for a URL that does not point back; Google ignores one-way annotations, so the cluster does not form (fail, severity 4, fixable: proposed, confidence established). evidence.observed quotes the one-way <link>.
  • M20.hreflang.invalid_bcp47 — e.g. hreflang="en-UK" (fail, severity 3, fixable: auto, confidence established; recommend en-GB). One bad value invalidates that entry, not the whole set.
  • M20.hreflang.missing_self — the page is absent from its own alternate set (fail, severity 3, fixable: auto, confidence established).
  • M20.hreflang.canonical_conflict — an hreflang URL whose rel=canonical points at a different page, which neutralizes the cluster (fail, severity 4, fixable: proposed, confidence established; cross-check M2).
  • M20.hreflang.missing_xdefault — the cluster has no x-default fallback (warn, severity 2, fixable: auto, confidence directionalx-default is recommended, not required, and its absence degrades selector routing rather than breaking the cluster).
  • M20.lang.mismatch<html lang> disagrees with the locale this URL claims in its own hreflang entry (warn, severity 2, fixable: auto, confidence directional).
  • M20.hreflang.not_applicable — monolingual site (not_applicable, severity 0). Platform-conditional ids. This module also emits 1 id that fires only when profile.json names the platform (shopify). It is indexed in references/routing.md § Platform-conditional finding ids and specified in references/platforms/<id>.md §10.

Each finding: verification.reproduce runs the hreflang-check command above; expected_impact is banded + confidence-tagged (no naked %).

Honesty

  • hreflang is a targeting/clustering signal, not a ranking boost: it selects which existing URL to show in a locale, it does not raise rankings. Don't sell it as a ranking lever.
  • hreflang does not fix thin or machine-translated content, and it is not a substitute for rel=canonical — the two work together.
  • Bing and Yandex use it weakly to not at all; the documented beneficiary is Google. Don't claim cross-engine parity.
  • Reciprocity cannot be asserted from one page. If the alternates were not fetched within the crawl budget, the finding is needs_api — a one-sided view is not evidence of a one-way link.

Signals

GitHub stars
59
Forks
5
Last commit
Sep 2026
Advanced
Catalog kind
skill
Gateway key
seo-international
Source
github.com/hainrixz/claude-seo-ai