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Hreflang & International SEO · agricidaniel | DecimalAI

marketingby agricidaniel

Hreflang & International SEO

agricidaniel/seo-hreflang

Source agricidaniel/claude-seo ↗License MIT

Hreflang and international SEO audit, validation, and generation. Detects common mistakes, validates language/region codes, and generates correct hreflang implementations.

SkillScore86Maintained

Automatic

Marketing & Content pack

Last verified 9/19/2026

What it changes

Passed 19 of 22 test cases with the skill, and 16 of 22 without it.

Without skill73%

With skill86%

Checks it passed that the model alone missed

The response states that only one x-default tag is permitted per set of alternate URLs.
The response recommends noting whether the client is an aggregator or direct supplier in the audit report.
The response notes that the Search Console International Targeting report and manual country targeting setting were removed in 2022.

3 fixed16 passed either way3 still failing0 broke

Pass-rate lift: +14 pp
Tokens: +135%
Agent turns: 0%
Response time: -17%

Model gemini-3.6-flashMeasured 9/19/2026v2 · latest is v319 of 22 cases passed with skill

Tokens, turns and time describe resource use, not a dollar price.

This benchmark measured an earlier version of the skill.

A newer attempt on gemini-3.6-flash on 10/2/2026 did not produce a publishable comparison (not comparable). The snapshot above is the previously measured run.

Use this skill

Save it into your project's skills folder. Claude Code picks it up in its next session.

curl -fsSL --create-dirs -o .claude/skills/agricidaniel-seo-hreflang/SKILL.md https://app.decimal.ai/s/agricidaniel-seo-hreflang/SKILL.md

Want it pinned and updatable? pip install "decimalai>=0.15", then decimalai skills add agricidaniel-seo-hreflang, and start Claude Code with claude --plugin-dir "$(git rev-parse --show-toplevel)/.agents"

1 · One-time — install the CLI (docs ↗)

pip install "decimalai>=0.15"

2 · Get the skill — writes .agents/skills/agricidaniel-seo-hreflang/ and pins it in .decimal/skills.lock

decimalai skills add agricidaniel-seo-hreflang

No CLI? Get the same file — curl · raw file

curl -fsSL --create-dirs -o .claude/skills/agricidaniel-seo-hreflang/SKILL.md https://app.decimal.ai/s/agricidaniel-seo-hreflang/SKILL.md

Raw file: /s/agricidaniel-seo-hreflang/SKILL.md ↗ · machine-readable summary at /s/agricidaniel-seo-hreflang.json ↗

Safety checks: 3 of 3 passed

Code scan CleanIntent PassedContent Clean

See it in action

One of 3 test cases the skill fixed. Same model, same prompt, with and without the skill.

1 of 3

Prompt

Where in Google Search Console should our SEO team go to set country targeting for our regional domains, and what report tracks international targeting settings in 2026?

What was checked, without and with the skill
Checked	Without skill	With skill
The response notes that the Search Console International Targeting report and manual country targeting setting were removed in 2022.	Missed	Passed
The response clarifies that hreflang annotations are the primary remaining technical mechanism for regional targeting.	Passed	Passed

case-11 · gemini-3.6-flash · 9/19/2026 · answers are capped and redacted

What's inside

The instructions your model reads when the skill loads.

SKILL.md274 lines5 files

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

Recommended when a selector/fallback URL exists: 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)
An optional ISO 15924 script subtag is the documented, official mechanism for script: zh-Hant (Traditional) / zh-Hans (Simplified). Script may combine with a region, e.g. zh-Hans-US is valid (language + script + region).
Common errors:
- eng instead of en (ISO 639-2, not valid for hreflang)
- jp instead of ja (incorrect code for Japanese)
- zh is valid but ambiguous for script-specific pages; prefer zh-Hans or zh-Hant when targeting a script

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)
A country code alone is invalid, you cannot specify a region without a language (Google's own bad example is be, which is actually the Belarusian

Track record

Benchmark

19 / 22

test cases passed, vs 16 / 22 without

Adoption

Users: 0
Times used: 0

Safety and source details

SkillSafety

✓ 3 of 3 passed

Code scan15 of 15 checks clean

0 critical · 0 warning · 0 info — scanner v5 — 10/1/2026

View 15 scanner checks

live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing

IntentSafe

LLM judge · does the skill do what it claims

ContentClean

LLM judge · policy & harmful-content review

Source

Imported

agricidaniel / claude-seo

skills/seo-hreflang/SKILL.md

View on GitHub ↗

License MITImported 10/8/2026Version v3Bundled 4 files

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More skills from the same source and nearby in the registry, with their headline benchmark lift.

Ready to supercharge your AI agents?

See it in action

What's inside

Hreflang & International SEO

Validation Checks

1. Self-Referencing Tags

2. Return Tags

3. x-default Tag

4. Language Code Validation

5. Region Code Validation

Track record

Benchmark

Adoption

SkillSafety

Source

Other skills for the same job

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