If you have taken measures to ensure that the probability is that low, yes, that is an example of a strong engineering control. You don't make a hash by just twiddling bits around and hoping for the best, you have to analyze the algorithm and prove what the chance of a collision really is.

How do you drive the probability of some series of tokens down to some known, acceptable threshold? That's a $100B question. But even if you could - can you actually enumerate every failure mode and ensure all of them are protected? If you can, I suspect your problem space is so well specified that you don't need an AI agent in the first place. We use agents to automate tasks where there is significant ambiguity or the need for a judgment call, and you can't anticipate every disaster under those circumstances.