My new criteria for determinism is whether or not the agent will use the same tool in the same way given a constant scenario over time.

With latest models I'd have to say we have satisfied this criteria. I've ran tests through complex workflows that have hundreds of interactions many times on end without experiencing a single failure. The business is satisfied with this, so I see no reason to continue chasing the rabbit.

The developers who are having the worst time right now are often chasing that rabbit all the way back through the wardrobe into Narnia. You'll never actually catch it. Not for all scenarios and platforms at the same time.

This gets back to that conversation about first principles thinking vs higher order thinking. Are we more interested in the ideological purity of a thing, or the practical outcomes that will eventually result?