This is exactly the issue I would like to prevent. Some of these tags seem useless as these will not yield you any traffic from google. (forum, discussion, practical) Nor are these tags useful for your users.
I quickly made that prompt. You can make a prompt that fits your forum well and get 1-2 high competition keywords or phrases, 2-3 medium, and 3-4 low competition (beforehand, you can get top ranking keywords on your forums niche [1000+ keywords] and instruct it to use 1 or 2 if it fits the message, but if it can't, don't use any from your list and make a better one).
You make the prompt, so it's even better than a batch update because you can't prompt it differently each time.
If you could batch export to CSV, you could even include something along the lines of
"These keywords are for threads in AmazingTech's off-topic movie discussion. While we focus on tech, these tags should more accurately reflect tags that would be related to movies, streaming services, etc."
If you check the data that was used, there was not a lot to work off of, either.
This thread is for the general discussion of the forum Practical Caravan Forum. Please add to the discussion here.
I'm sure if I wanted to run a practical test on this, it would spit out the greatest reflecting tags, and tags that are exact match low competition (to rank for some searches that would get higher traffic on those because it's easier to rank for).
Certain commonly used useless words could be blacklisted like forum and discussion.
Since it's auto-manual, you can add that to the prompt without running a new batch update after 50,000 threads have processed and you notice that 1-5 tags were repetitive and don't really fit your forum. You could 1) manually remove them, or 2) get the maximum number of tags that reflect your site the first time.
Edit 2: In the case of the data used, I would want forum and discussion used as tags because it's for a directory of forums. So, I wouldn't have blacklisted them.
But, best of all, you can rerun a batched export with a tweaked prompt that can get you even better keywords for import over and over until you're satisfied. With the API batch update, it's one and then done for most people's budgets.
Edit: You could also add a "matrix" to the prompt and upload all files at once. Blacklist "forum" and the obvious, but something like "Give me 1 keyword or tag that can be used to cross-reference up to 15% of the messages if possible. But, don't force a tag into a message if it doesn't fit just to make the quota. Only use tags that fit the forum's niche and message and make sense to cross-link the content if the discussions are more than 40% similar".
Then, you won't get the "forum" output, but you might get 2000 threads with "television" if the messages across different forums discuss something on television to cross-link it better.