# Canonical > Use this to manage URL authority and prevent duplicate content issues across the storefront - Skill: `decocms/canonical` (Agent Skill) - Install (CLI): `npx skillmds@latest add decocms/canonical` - Raw SKILL.md: https://api.skillmd.com/api/skills/decocms/canonical/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Marketing & Growth - Author: decocms (https://skillmd.com/u/decocms) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/decocms/canonical --- Use this to manage URL authority and prevent duplicate content issues across the storefront. This ensures search engines focus on the "master" version of a page, consolidating ranking power and protecting crawl budget. ## Canonicalization Strategy - Use a **self-referential** canonical tag on every unique product, category, and CMS page (the "clean" URL should point to itself). - Use **absolute URLs** (including `https://` and the full domain) to avoid ambiguity between environments, protocols (HTTP vs HTTPS), or subdomains. - Ensure the canonical target is **indexable**: it must return a `200 OK` status and must **not** have a `noindex` tag. ## E-commerce Specific Scenarios - **Faceted Navigation & Filters:** - Point the canonical to the **main category** for URLs created by sorting (`?sort=price`), view toggles (`?view=grid`), or tracking parameters (e.g., `?utm_source=...`). - Only allow a unique canonical if the filter creates a distinct, high-value landing page (e.g., a specific "Brand + Category" combination with high search volume). - **Product Variations:** - If a product has multiple URLs for different colors/sizes but the content is nearly identical, point the canonical to the **primary product version**. - If each variation is a distinct marketing asset with its own unique description and SKU, use a self-referential canonical for each. - **Cross-Categorization:** When a product lives in multiple categories (e.g., `/sale/product` and `/electronics/product`), pick the **most relevant** or original path as the canonical to avoid splitting authority. ## Technical Rules - **Single Tag Policy:** Ensure only **one** `` exists in the ``. Multiple tags cause search engines to ignore the instruction entirely. - **Sitemap Alignment:** The URL defined as canonical **must** match the URL listed in the `sitemap.xml`. Discrepancies send conflicting signals to crawlers. - **Pagination:** For paginated results (e.g., `?page=2`), use a **self-referential** canonical. Do **not** point page 2 to page 1, as this prevents search engines from discovering products deeper in the catalog.