Guide · Agent skill
How to use the Canonical URL Audit agent skill
Updated · written with AI from the project's own documentation and checked against our catalogue data
The canonical-url skill teaches an AI agent to review a website for canonical URL tags, the link element that tells search engines which version of a page is the preferred one when duplicates exist. This guide explains what an agent skill is, how to install this one, how to ask for an audit in plain language, and where its limits are. After reading, you will be able to install the skill, trigger a canonical check, and judge the agent's suggested fixes before applying them.
Canonical URL Auditthedaviddias/Front-End-Checklist · MIT Download the skill Quick start
- 1Download the ZIP. Download the canonical-url skill ZIP from this page.
- 2Unzip into a skills folder. Unzip it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder.
- 3Or upload in the Claude apps. In the Claude apps, go to Settings → Capabilities → Skills and upload the skill.
- 4Ask for a canonical audit. Describe the pages or templates to check in plain language that mentions canonical URLs.
- 5Review the findings. Check the routes the agent flags and the rendered HTML and headers it reports.
- 6Test before deploying. Apply any suggested change to a test environment first, since wrong canonical tags can affect search ranking.
What is an agent skill and what does this one do?
An agent skill is a folder of instructions that an AI agent loads when a task matches the skill's description. This skill is for auditing canonical URLs. Duplicate content from URL parameters, www vs non-www, or pagination can dilute ranking signals, and canonical tags consolidate those signals to the preferred URL.
Once installed, the agent checks the rendered HTML and HTTP responses rather than only source files. It flags routes or templates where the canonical tag is missing or wrong, and explains how to fix it.
- Checks whether a page has a canonical URL tag pointing to the correct preferred version
- Recommends absolute URLs including protocol and domain
- Treats self-referencing canonicals as a best practice
- Describes how to verify the final page output
How do you install the canonical-url skill?
Download the ZIP for this skill from this page and unzip it. You can place the folder in one of two locations: your personal skills directory at ~/.claude/skills/, or a project's .claude/skills/ directory if you want the skill limited to one codebase.
You can also upload the skill in the Claude apps under Settings → Capabilities → Skills.
- Personal: unzip into ~/.claude/skills/
- Per project: unzip into the project's .claude/skills/ folder
- Claude apps: Settings → Capabilities → Skills, then upload
Which files does the skill include?
The skill contains two files. SKILL.md holds the skill's description and the check, fix, explain and code review instructions. references/rule.md holds the fuller rule page, including a code example of a canonical link element and a table of when to use canonical tags.
- SKILL.md
- references/rule.md
<head>
<link rel="canonical" href="https://example.com/products/widget" />
</head>How do you trigger the skill with a natural request?
You do not need a special command. Describe the task in plain language that mentions canonical URLs, metadata, or indexability, and the agent will load the skill when the request matches its description. Be specific about the site or the routes you want reviewed.
The skill's description covers auditing metadata, crawlability, structured data and indexability, so requests about those topics related to canonical URLs are the ones it fits best.
- "Check the canonical URL tags on my product pages and tell me which ones are missing or wrong."
- "Review my blog templates for canonical tag problems, including pagination."
- "Audit how www and non-www versions of my site set their canonical URLs."
- "Before launch, check that my routing sends every page to a correct canonical URL."
What should you expect the agent to produce?
The agent reports the exact routes or templates where search-facing output violates the rule, and describes how to verify the final page output. It will suggest adding or correcting the canonical tag in the head section.
Ask the agent to show the rendered HTML and response headers it checked, so you can confirm its findings yourself before changing anything.
- List of routes or templates with missing or incorrect canonical tags
- Suggested corrections in the head section
- Verification steps for the final page output
What does the skill need, and what are its safety limits?
The skill lists no requirements. It does not run scripts and does not use the network, and the files give no tooling beyond what the agent already has. The skill is licensed under MIT.
Because the skill only covers canonical URLs, it is not a full SEO audit. Its suggested tag changes could affect search ranking if applied incorrectly, so test them before deploying to a production site.
- Requires: nothing listed
- Runs scripts: no
- Uses network: no
- Licence: MIT
- Do not apply suggested changes to a production site without checking them first
Tips for getting useful results
Give the agent a precise scope, such as a list of routes or one template, so it does not guess at the whole site. Tell it which URL you consider the preferred version, for example https with or without www, so it can judge the canonical tags against that choice.
Keep URL normalization consistent. The rule page notes that canonical tags work best when rules such as lowercase paths and trailing-slash policy already point to the same preferred URL.
- Name the preferred domain and protocol up front
- Share the routes or templates to review
- Ask for the rendered HTML, not only the source files
- Check URL normalization rules alongside canonical tags
What people use it for
- Finding product pages that lack a canonical tag after a template change
- Checking that paginated listing pages point to the correct canonical URL
- Confirming www and non-www versions resolve to one preferred URL
- Reviewing routing and templates on a pre-launch checklist
Frequently asked questions
Is the canonical-url skill free to use?
The skill is licensed under MIT, as stated on this page. The source does not list any prices, so check the licence file in the download for the full terms.
What do I need to install the canonical-url skill?
The skill lists no requirements. You download the ZIP, unzip it into ~/.claude/skills/ or a project's .claude/skills/ folder, or upload it under Settings → Capabilities → Skills in the Claude apps.
Does the skill run scripts or access the internet?
No. The skill runs no scripts and uses no network access. It relies on the instructions in its files and on what the agent already has.
What is a canonical URL tag?
A canonical URL tag is a link element in the head section of a page, such as link rel canonical pointing to a preferred address. It tells search engines which version of a page to index when duplicates exist.
Can the skill do a full SEO audit?
No. It covers only canonical URLs. For other technical SEO checks you will need other tools or skills.
Should I trust the agent's suggested canonical changes?
Verify them first. The source warns that incorrectly applied canonical tag changes could affect search ranking, so test changes before using them on a production site.
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Our verdict
Use this skill if you are a front-end or full-stack developer, or an SEO-minded marketer, who wants an agent to check canonical tags on templates and routes before launch. Pick something else if your site is not publicly indexed, if you need a full SEO audit, or if you plan to apply the agent's changes to production without checking them.
Download the skill