Via https://www.stainless.com/blog/stainless-is-joining-anthropi... that's exactly what seems to have happened:

> As we focus on Claude Platform capabilities and connecting agents to APIs, we’ll be winding down all hosted Stainless products, including our SDK generator. Starting today, new signups, projects, and SDKs will not be available.

> If you’re a Stainless customer, visit app.stainless.com/transition for help transitioning from Stainless-managed products to other options. As always, you own the SDKs you’ve generated to date, and have full rights to modify and extend them however you wish.

Looks like contracts (enterprise, even!) matter again