pi-agents-config: Skill for Claude Code

.pi/agent/skills/seo-hreflang/SKILL.md

seo-hreflang is a skill for Claude Code, Codex from niclejeune/pi-agents-config. It costs 71 tokens per session (2,071 once invoked), scanned A, a copy of seo-hreflang, MIT.

A review and generation guide for hreflang tags, which tell search engines which language or regional version of a webpage to show.

In plain words
What is it for?
Use it to audit, validate, or create hreflang tags in HTML, HTTP headers, or XML sitemaps for multilingual and multi-region websites.
Why use it?
It finds broken links between translated or regional pages and incorrect language or region codes that can weaken international search signals.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

This is niclejeune/pi-agents-config's own configuration. It tells Claude Code and Codex how to work on pi-agents-config itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything pi-agents-config configures →

Reuse

Borrowing it

Nothing to install: this file belongs to niclejeune/pi-agents-config. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/niclejeune/pi-agents-config/main/.pi/agent/skills/seo-hreflang/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/niclejeune/pi-agents-config

Made for: Claude Code, Codex.

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 seo-hreflang

README.md
[![agentmods](https://agentmods.dev/badge/skills/niclejeune/pi-agents-config/seo-hreflang/github.svg)](https://agentmods.dev/skills/niclejeune/pi-agents-config/seo-hreflang)
Your own site
<a href="https://agentmods.dev/skills/niclejeune/pi-agents-config/seo-hreflang"><img src="https://agentmods.dev/badge/skills/niclejeune/pi-agents-config/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 seo-hreflang

Your own site · 80×15
<a href="https://agentmods.dev/skills/niclejeune/pi-agents-config/seo-hreflang"><img src="https://agentmods.dev/badge/skills/niclejeune/pi-agents-config/seo-hreflang.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,071 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 84% 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 $0.00071 $0.02071
Opus 5 $0.00036 $0.01035
Sonnet 5 $0.00014 $0.00414
Haiku 4.5 $0.00007 $0.00207

Measured 12d ago against content hash 033dd5f6dd6a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

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

84% identical to seo-hreflang — 117 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.

.pi/agent/skills/seo-hreflang/SKILL.md · 185 lines

How it starts

The opening of the file, as written. The whole thing — 185 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 · 185 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 · 185 lines · 71 tokens per session scan A 033dd5f6dd6a

Subscribe to this mod's changes

seo-hreflang is a skill published in the GitHub repository niclejeune/pi-agents-config (1 stars, last pushed 4mo ago), licensed MIT. It adds 71 tokens to every session and 2,071 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 84% identical to seo-hreflang, differing in 117 lines, and is treated as a copy.

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