what that one-line config change tells us about "subscription vs API" in Agent economics. To avoid paying a separate API bill, I switched the workflow to reuse my Claude Pro subscription. The interesting signal: model labs themselves are blurring the API-vs-subscription boundary. Subscription becomes the API price ceiling — $20/mo Pro and $100/mo Max are the hidden anchor for the entire Agent stack. Every middleman charging an API markup (harness, aggregator, proxy) needs to model two curves now: API-billed vs OAuth-billed users.