Shopify serves a robots.txt it writes for you, and you override it by adding a template to your theme rather than by editing a file. Shopify calls this an unsupported customisation, which means their support will not help you with it, so read the note below before you start.
Adding robots.txt.liquid
Duplicate your theme. Same reason as everywhere else on Shopify: this is your undo.
Online Store, then Themes, then Edit code.
Add a new template and choose robots. Shopify creates
robots.txt.liquidfor you.Start from the default rules and add yours. The template renders Shopify’s own rules through a Liquid object, so keep that and add to it rather than replacing the lot.
Save, then open
yourdomain.com/robots.txtto confirm what is being served.
Blocking a crawler here keeps it off your pages on the open web. It does not stop Shopify sending your product data to AI shopping channels through its own catalogue, which is a separate setting under Sales channels.
Apps and firewalls
Bot protection and fraud prevention apps are the usual cause when the file is clean. They block by user agent and they rarely tell you. Look at anything you have installed for security, and at Cloudflare if you put it in front of the store yourself.
Which crawlers matter most
The four answer crawlers are OAI-SearchBot, ChatGPT-User, PerplexityBot and Perplexity-User. Those decide whether you can be quoted today, and blocking them is what produces a failure rather than a warning.
If your screens do not look like this, the wording has moved rather than the setting. Search your platform for the words in bold above. If you still cannot find it, send us the scan link and we will tell you where it is on your setup.