Had no luck generating AI tags to documents (except one time, never again). AI is local and working for any other task except tags…
Which local AI app and model actually? This can make a huge difference. And what kind of documents did you try to tag?
DTTG 4 4.0.1 (18078) runs on iPad Pro 13“ M5 2TB Cellular - AI is LMStudio (on 64GB local MBP 16“ M1Max) - LLM is gpt-oss-20b with 8192 context
Documents: any: Plain Text / PDF / Word / … (the one it worked once was PDF, even a 2nd try on that document after deleting the tags resulted in …nothing…). Doing the same on MBP with DTP 4 worked as it should referring to same LLM and same AI (LMStudio) with same url (except on MBP its „localhost“ instead of IP.
Any other use of this url works as it should.
Does it work again after restarting DEVONthink To Go?
Unfortunatelly not. Even not, if iPad has been restarted. Activity shows that tags were about to be generated, LMStudio trace says the client is working on tags. And the task ends with 100%. But: no tag at all on DTTG4.
Is the option to use only existing tags en- or disabled?
Disabled
Commercial AI is working just fine… well, let’s say it’s producing a result.
Here are suggestions for a receipt from GPT 5 (Mini)…
Mine to. At DTP4. But not with DTTG4. But something strange happened minutes ago whilst testing: Focus jumped from document to document making at least 20 documents going away until I killed DTTG4. Just searching for them. BTW: sometimes the left Upper corner selection symbol is going away and you are stuck inside the group you are in. Until you stop DTTG4 the hard way. Weird.
Groups show up as tags now
Try to reproduce this and see if you can make it happen.
That would be the product of disabling Exclude Groups From Tagging in the Info popup for a database in DEVONthink To Go or File > Database Properties in DEVONthink.
Intentionally or „ouch“?
No offense, only for understanding, since currently there is little documentation about DTTG4s specific configuration - at least found by me.
I’m not offended as I’m not sure what you’re referring to 
I still have the problem with the AI and the tags that aren’t generated, and stumbled across the topics I mentioned earlier…
We’ve investigated the issue and fixed it for DEVONthink To Go 4.0.4.