Zendesk App Tools was a major pain in the ass to install, I was plagued with errors and ended up having to Google a quite a lot. Hopefully this saves you some time.
Step 1: Installing and Updating Xcode
If you don’t have Xcode installed you should install it, if you already have Xcode make sure you’re up to date.
Once you have Xcode installed you should open it and make sure you’ve accepted its terms and conditions and allowed it to finish setting up.
Step 2: Installing on the Command Line
Open a Terminal window, you should first install Rake:
sudo gem install rake
One of my errors related to having a later version of Thin than what is needed. As ZAT needs a specific version of Thin you should install it specifically:
gem install thin -v 1.7.2 -- --with-cflags="-Wno-error=implicit-function-declaration"
Finally, you should install Zendesk App Tools:
sudo gem install zendesk_apps_tools
Step 3: Run Zendesk App Tools
To run ZAT you should download your theme from your Zendesk account, it will download as a zip file. Unzip it and cd into the new theme directory. Then start ZAT:
zat theme preview
You will be prompted for your Zendesk login credentials including domain, user and password. If it starts up successfully you will see a URL displayed in the terminal window, load it in a browser. Now any changes you make on your local theme will be available immediately on reload of the browser window.