Guide · Agent skill
How to use the Google Tag Manager Performance Audit agent skill
Updated · written with AI from the project's own documentation and checked against our catalogue data
The gtm-present skill is an agent skill that tells an AI agent how to review a website's Google Tag Manager (GTM) setup for performance problems such as blocking scripts, too many tags and heavy page weight. It is written for front-end developers, marketers and site owners whose pages load slowly and who use GTM. After this guide you will know what the skill does, how to install it, how to ask for an audit in plain language and what to check before accepting its suggestions.
Google Tag Manager Performance Auditthedaviddias/Front-End-Checklist · MIT Download the skill Quick start
- 1Download the skill ZIP. Get the gtm-present ZIP from the rule page on the directory.
- 2Unzip into a skills folder. Extract 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.
- 4Describe the slow page. Ask in plain words about slow page loads or heavy assets on a site that uses Google Tag Manager.
- 5Provide measurements. Share DevTools, Lighthouse or field data so the agent can confirm the real bottleneck.
- 6Review the suggestions. Check each proposed fix, such as removing unused tags or loading asynchronously, against your analytics needs before applying it.
What is an agent skill and what does gtm-present make the agent do?
An agent skill is a folder of instructions that an AI agent loads when a task matches the skill's description. This one is named gtm-present and is listed in the Front-End-Checklist repository under skills/gtm-present. Its description is: use it when auditing slow page loads, heavy assets, or rendering delays related to Optimize Google Tag Manager implementation, and verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.
When installed, the agent reviews the GTM setup for blocking scripts, too many tags and heavy page weight. It is instructed to confirm the real bottleneck using DevTools, Lighthouse or field data before recommending changes. It then suggests fixes such as removing unused tags, loading asynchronously, or moving to a server-side GTM setup.
- Checks that the GTM snippet is placed correctly in the head and that its impact is measured with Lighthouse.
- Looks for unused tags and triggers that add execution cost.
- Recommends asynchronous loading and, where relevant, server-side GTM.
- Asks the agent to name the exact files, requests or rendering steps that add cost and the method used to measure them.
How do you install the gtm-present skill?
Download the ZIP of the gtm-present skill from the rule page on our directory. Unzip it into your personal skills folder at ~/.claude/skills/, or into a project's .claude/skills/ folder if you want the skill available only in that project.
If you use the Claude apps, you can instead upload the skill under Settings → Capabilities → Skills.
- Personal install: ~/.claude/skills/ (available across your projects).
- Project install: .claude/skills/ inside the project folder (available only there).
- Claude apps: Settings → Capabilities → Skills, then upload the skill.
What files does the skill contain?
The skill has two files. SKILL.md holds the main instructions, including a quick reference, a check step, a fix step and a code review step. references/rule.md holds longer implementation details and code examples, including a recommended asynchronous GTM snippet. SKILL.md points the agent to that reference for full detail.
- SKILL.md: the instructions the agent follows.
- references/rule.md: extended guidance and code examples for GTM.
How do you trigger the skill with a natural request?
You do not need a special command. Describe the problem in plain words that match the skill's purpose: slow page loads, heavy assets or rendering delays on a site that uses Google Tag Manager. The agent should recognise the match from the skill's description.
Good requests name the site or page, the symptom and the GTM context. Mention any measurements you already have, because the skill asks the agent to verify the bottleneck before recommending changes.
- "My product page is slow. We use Google Tag Manager. Can you find out whether our tags are causing it?"
- "Review our GTM container for tags that block rendering, and check them with Lighthouse before suggesting changes."
- "Should we move our tracking to server-side GTM to speed up the site? Audit the current setup first."
What do you need before running an audit?
The skill's metadata lists no required tools, it does not run scripts and it does not use the network. The skill's own instructions rely on measurement tools such as DevTools and Lighthouse, or on field data, to confirm the bottleneck. Having access to the page and those tools lets the agent verify its findings rather than guess.
- Access to the page you want audited.
- DevTools, Lighthouse or field data to confirm the real bottleneck.
- Your analytics requirements, so fixes do not break the tracking you need.
What are the safety notes for gtm-present?
The skill runs no scripts and uses no network access, according to its listing. It gives advice and review only. It does not edit your live GTM containers or change your accounts.
Be careful when applying the suggestions. The skill's listing warns that fixes applied without checking your analytics needs may cause tracking loss. Review each proposed tag removal against what your team measures before making it.
- No scripts are run and no network use is declared.
- It does not edit live tag containers automatically.
- Check analytics needs before removing or delaying any tag.
Tips for getting useful audit results
Ask for measurements, not opinions. The skill is built to confirm the bottleneck in DevTools, Lighthouse or field data first, so supply those results where you can. Ask for exact files, requests or rendering steps, since the skill's code review step asks for them.
Use the GTM snippet guidance as a reference point. The reference file recommends loading GTM asynchronously so it does not block the initial HTML parsing.
- Run Lighthouse on the page and share the performance report with the agent.
- Ask which tags run on the slow page and why.
- Treat server-side GTM as a bigger change that needs a planning discussion with your team.
What people use it for
- Finding which tags delay rendering on a slow product or landing page.
- Cutting unused tags and triggers from a long-standing GTM container.
- Checking that the GTM snippet loads asynchronously.
- Deciding whether a server-side GTM setup is worth planning for your team.
- Explaining to a marketing team how their tracking tags affect page speed.
Frequently asked questions
How do I install the gtm-present skill?
Download the ZIP from the rule page and unzip it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder. In the Claude apps, you can upload it under Settings → Capabilities → Skills.
Does gtm-present require anything else to run?
The listing lists no required items, runs no scripts and uses no network. For useful results you still need access to the page and tools such as DevTools or Lighthouse to verify the bottleneck.
Is gtm-present free to use?
The skill is published under the MIT licence, as listed on the directory page. Check the licence file in the source repository for the full terms.
Will the skill change my Google Tag Manager container for me?
No. The skill gives advice and review only and does not edit live tag containers or change accounts. You apply any changes yourself after checking them.
Can the skill help if my site does not use Google Tag Manager?
Not really. The guidance is specific to Google Tag Manager, so it is not suited to sites that do not use it.
How is this different from just running Lighthouse?
Lighthouse measures the page, while this skill is set up to review the GTM implementation, confirm the bottleneck with DevTools, Lighthouse or field data, and suggest specific fixes such as removing unused tags or moving to server-side GTM.
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Our verdict
Use gtm-present if you have a site on Google Tag Manager that loads slowly and you want an agent to review your tags against measured evidence before changing anything. Pick something else if your site does not use GTM, or if you want a tool that edits your tag containers automatically.
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