OpenParable
Skip to content
← Back to skills

Canonical Header

Business
canonical-header

Canonical Header is an Agent Skill for business published in the thedaviddias/Front-End-Checklist repository on GitHub: a SKILL.md instruction file an AI agent can load to do this task.

Use when auditing metadata, crawlability, structured data, or indexability related to Sync HTML canonical tags and Link headers. Verify the rendered HTML and HTTP response rather than relying only on source files.

View on GitHub ↗
QUICK START

How to use this skill

Bring this guide into your coding agent with a prompt tailored to the tool you use.

  1. Open your project in Codex.
  2. Copy and paste the prompt below.
  3. Review files and risks before approving any action.
Prompt to paste
Inspect the Agent Skill at https://github.com/thedaviddias/Front-End-Checklist/blob/HEAD/skills/canonical-header/SKILL.md and all supporting files. Report provenance, permissions, scripts, dependencies, and security risks. Propose an exact installation into .agents/skills/canonical-header, but wait for my approval before writing files or running scripts.

Copying this prompt does not install or run the skill. Review third-party files before use.

Sync HTML canonical tags and Link headers

Conflicting canonical-url signals can lead search engines to ignore both declarations, potentially causing duplicate content issues and incorrect indexing.

Quick Reference

  • Ensure the rel="canonical" tag in your HTML matches the Link canonical-url header if both are used
  • Avoid sending conflicting signals to search engines about the primary version of a page
  • Maintain consistency across all methods of declaring your canonical URL

Check

Compare the HTML canonical tag with the HTTP Link header to ensure they point to the exact same URL.

Fix

Update either the HTML tag or the HTTP header so that they provide a consistent canonical URL signal.

Explain

Explain the risks of sending conflicting technical SEO signals to search engine crawlers.

Code Review

Review metadata generation, rendered HTML, structured data, and response headers related to Sync HTML canonical tags and Link headers. Flag exact routes or templates where search-facing output violates the rule, and describe how to verify the final page output.

For full implementation details, code examples, and framework-specific guidance, see references/rule.md.

Rule page: https://frontendchecklist.io/en/rules/seo/canonical-header