Interestingly it seems 80% of the cost is in the cached tokens.

I do not know whether that is typical, or indicative of conversations with too many turns.

Not that I would worry about this on a subscription plan, but at work where we are billed at API rates, I try to move to new conversations as often as possible.

For agentic development upwards of 90% is pretty normal!

For example, if you make Claude Code explore a codebase, write a plan based on it and your requirements, do a few iterations of further specifying and altering it, and afterwards let it work for let's say 2-4 hours.

Sub-agents and dynamic workflows do alter the numbers a bit, but not to a crazy degree in the long run.