ToME: the Tales of Maj'Eyal

I don't really understand how the behaviors for the golem work.
Like what is the difference between tank and melee?

I've looked at the guides in spoilers and none of them reveal anything about the different behaviors.
Is there someplace that explains the differences between the behaviors?

Right now, I just use talent usage and leash distance but If I can further fine tune my golem's AI with the behaviors then all the better.

I don't know of any guide/documentation for the behaviours for your Golem.

Presumably, it would help set priorities, though; a Golem set to melee wouldn't waste time with the eyebeams, and would move straight to rushing. Meanwhile the tank would move as little as possible and focus on shields. Probably. I just keep it on the default and hope for the best.

I've tried experimenting with them but I never noticed any changes.

Maybe behavior has little effect on the AI compared to leash and talent usage?