What it does
Compares a set of pages for near-duplicate content (same product across categories, paginated archives, print/AMP variants) and checks whether each has a canonical tag pointing to the right single version. Flags canonicals that point to a redirect, a noindexed page, or a different domain by mistake.
Install
This skill isn't packaged in an installable registry. It's a plain SKILL.md file you can copy directly. Copy it from the SKILL.md tab and save it at the path for your assistant:
Use it in your AI assistant
Claude Code
.claude/skills/canonical-url-checker/ (or ~/.claude/skills/canonical-url-checker/ for all projects)
GitHub Copilot (VS Code)
.github/skills/canonical-url-checker/
OpenAI Codex
.codex/skills/canonical-url-checker/
Cursor
.cursor/skills/canonical-url-checker/ (or ~/.cursor/skills/canonical-url-checker/ globally)
Compatibility
Any WordPress site. Canonical tags are read and written through the active SEO plugin (Yoast, Rank Math, SEOPress) or WordPress core's default rel=canonical if no plugin is active.
The complete SKILL.md for this skill:
---
name: canonical-url-checker
description: Use when a user suspects duplicate content issues or wants canonical tags checked across a set of WordPress pages. Triggers on "canonical tag", "duplicate content", "canonical check", or "which page should be canonical".
---
# Canonical URL Checker
## When to use
The user has pages that might be duplicates of each other (paginated pages, category/tag archives, product variants) and wants to confirm canonical tags point to the one version that should rank.
## Procedure
1. Identify groups of pages likely to be near-duplicates: same content under different URLs, paginated series, or parameter variants.
2. For each group, determine which single URL should be canonical based on which one is linked-to most, ranks currently, or is the most complete version.
3. Check each page's existing canonical tag against that intended target, and flag mismatches, self-referencing canonicals on a page that shouldn't be canonical, and canonicals pointing to a redirect or noindexed URL.
4. Present the mismatches with the current canonical, the recommended canonical, and why.
5. On approval, update the canonical tag through the site's SEO plugin field for each affected page.
## Guardrails
- Never set a canonical across two pages with genuinely different content, that hides one of them from search entirely.
- Leave paginated series pages (page 2, page 3 of an archive) self-canonical rather than pointing them all at page 1, unless the user's SEO plugin's documented pattern says otherwise.