I don't think there's that many bots/ai agents on here yet. There's a few repost boys for news feeds and things from other networks, but the ones I've seen are mostly declared as such.
I suspect Nostr hasn't quite reached the critical mass to attract the hoards of spam bots, but I suspect this is coming.
it could be an interesting experiment to run up a non spammy agent that knows "how to Nostr" and see how it goes.