GTM Tools are the Google Sheets extension of Simo Ahava's www.gtmtools.com. This Google Sheets extension is free to use, and the first version includes documentation building tools with which you can automatically generate documentation for your Google Tag Manager container, tags, triggers, and variables.

The documentation tools also include the option to mass-update notes across your tags, triggers, and variables. This is extremely useful when you want to add descriptions to these items to make it easier to understand what role each play in your container.