I've been working on an integrated deterministic/agent integrated system for a few months now. It basically runs an AI step to build a plan, which biases towards deterministic steps as much as possible but escalates back to AI when it needs to (for AI only capabilities or deterministic failures) so effectively (when I perfect it, I'm about 90% there) it can bounce back and forward as needed with deterministic steps launching AI steps and AI steps launching deterministic steps as needed.

Probably not explaining it very well but I think it's pretty effective at reducing token usage.