Connecting Shopify
Create a token in your admin so tragent can work out what to test.
Create a custom app
In your Shopify admin: Settings → Apps and sales channels → Develop apps → Create an app. Name it something you will recognise later, like 'tragent'.
Give it read access
Under Configuration → Admin API integration, grant read access to products and to the online store. tragent never needs write access to anything, and never asks for it.
Install and copy the token
Install the app, then copy the Admin API access token. It starts with shpat_ and is shown once. Paste it into tragent — it is encrypted before it is stored and no screen shows it again.
Check what tragent found
The Store setup page lists what it worked out. If something is blank, it says why — most commonly there is no out-of-stock product to test availability with, which is normal and not a problem with your store.
If your store is password-protected
A development store with a storefront password shows every visitor a login wall, including an agent. tragent says so rather than reporting nine failed stages, but you will need to lift the password in Online Store → Preferences before a check means anything.