Measure how Google Tag Manager affects page loading and rendering. Identify costly tags, triggers, and requests, then guide cleanup, asynchronous loading, or a move to server-side processing based on observed performance problems.
Use when auditing slow page loads, heavy assets, or rendering delays related to Optimize Google Tag Manager implementation. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.
This skill helps you investigate how Google Tag Manager (GTM) affects page loading and rendering. It reviews the number of tags and triggers, script placement, and loading methods. It identifies files and requests that cause unnecessary network activity, CPU work, or layout calculations, and explains the measurements used to confirm each issue.
Use it when a page with GTM feels slow or when you want to review a site that has accumulated tracking tags. DevTools, Lighthouse, and data from real usage help establish the cause. You can then consider changes with both tracking requirements and page speed in mind.
Recommendations assume that the problem has first been verified through DevTools, Lighthouse, real usage data, or similar measurements. Server-Side GTM is an option to assess. The improvement method should follow the performance problems actually measured.
This overview was written by AI (OpenAI Codex) from the public SKILL.md. Check the original below for the exact behavior.
AI rated this skill on four points using only the contents of its SKILL.md. Stars and popularity are not taken into account.
The total counts each point as A = 25, B = 15, C = 5. Rated by AI (OpenAI Codex) as of Oct 23, 2026. Treat it as a guide and read the original before installing.
Review the instructions the agent will receive before you install.
An unoptimized GTM setup can lead to significant main-thread blocking and increased page weight, slowing down the overall user experience.
<head> but audit its impactVerify that GTM is implemented correctly and evaluate its impact on page performance using Lighthouse.
Clean up unused tags, use asynchronous loading, and consider moving to a server-side implementation.
Explain how GTM affects performance and how to balance tracking needs with speed.
Review the routes, assets, and loading behavior that affect Optimize Google Tag Manager implementation. Flag exact files, requests, or rendering steps that add unnecessary network, CPU, or layout cost, and describe the measurement method used to confirm the issue.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/performance/gtm-present
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Create and review custom 404 pages that help visitors recover from broken or moved links through search and navigation. Check the rendered page and HTTP response so missing content returns a proper 404 status.
Audit or create a dedicated About page that explains a website’s purpose and identifies its people or organization. Review the rendered output and supporting information, including expertise and contact details, to find gaps.
Review and add automated accessibility checks for components, pages, and continuous integration workflows. Use axe-based tools to detect structural and attribute issues, while identifying checks that still need keyboard or screen reader testing.
Review sign-in, registration, multi-factor authentication, and account recovery for accessibility barriers. Find blocked paste, difficult code entry, and inaccessible backup methods, then suggest authentication paths that support password managers, autofill, or device approval.
Review form errors, success messages, and live updates so screen reader users receive important notifications. Check the HTML delivered to the browser, announcement settings, display duration, and dismissal controls, then identify specific elements that need changes.
Review HTML tables so screen reader users can understand how headers and data relate. Check header markup, table descriptions, and merged cells, then identify specific fixes and ways to verify them.