If you sign up to use IBM Cloud Natural Language Understanding-11 then ClassifAI will enable you to Automatically tag Posts and Automatically tag Pages.
So let’s see what happens when I save this post.
There’s a toggle in the Settings > ClassifAI panel that allows me to Automatically tag content on update.
Also, on the All Posts admin page there’s a Classify link.
When I first created this post it classified it as Gutenberg, which is probably the default category.