The thread Exclude site from ChatGPT scraping in the Help Center contains what you need to put in a

file in order to keep ChatGPT from scraping your site.

As explained at Search engine indexing in the Help Center:

By default creates a robots.txt file for your site that allows Google and other search engines to index all the blog posts and pages on your site.

That page goes on to explain how to customise robots.txt.

Then add the text [@sod]( provided at the first link above.