As long as I have a Claude subscription, why do they care what harness I use to access their very profitable token inference business?
Anthropic's cogs is rent of buying x amount of h100s. cost of a marginal query for them is almost zero until the batch fills up and they need a new cluster. So, API clusters are usually built for peak load with low utilization (filled batch) at any given time. Given AI's peak demand is extremely spiky they end up with low utilization numbers for API support.
Your subscription is supposed to use that free capacity. Hence, the token costs are not that high, hence you could buy that. But it needs careful management that you dont overload the system. There is a claude code telemetry which identifies the request as lower priority than API (and probably decide on queueing + caching too). If your harness makes 10 parallel calls everytime you query, and not manage context as well as claude code, its overwhelming the system, degrading the performance for others too. And if everyone just wants to use subscription and you have no api takers, the price of subscription is not sustainable anyway. In a way you are relying on others' generosity for the cheap usage you get.
Its reasonable for a company to unilaterally decide how they monetize their extra capacity, and its not unjustified to care. You are not purchasing the promise of X tokens with a subscription purchase for that you need api.