The closed nature is one thing, but the opaque billing on reasoning tokens is the real dealbreaker for integration. If you are bootstrapping a service, I don't see how you can model your margins when the API decides arbitrarily how long to think and bill for a prompt. It makes unit economics impossible to predict.

Doesn't ClosedAI do the same? Thinking models bill tokens, but the thinking steps are encrypted.

You just have to plan for the worst case.