Agreed, and it's a point the series runs into head-on. One clarification on Day 03: the repo size is only the up-front estimate. The meter itself records the usage the server reports on every request, so whatever is in the transcript gets counted, tool outputs included. Neither side of the ledger is guessed.

You're right about where the pressure moves, though. Once the agent can call tools (Day 06), file reads pile up in the transcript and soon outweigh everything else. Day 08 is about exactly that: tools that return a bounded slice of a file instead of the whole thing. A later memory day handles what to drop from a long transcript without breaking it.