If you use API billing, you can use them from anywhere. But using Claude Code with a Max subscription is massively cheaper for programming. You should never use Claude models for programming through API billing, unless forced. The difference will easily rack up to thousands of dollars for heavy users.

It's not allowed, it spoofs claude code's requests.

https://github.com/patriceckhart/zot/blob/main/packages/prov...

Claude models are usable through certain github copilot plans, so that's a counterexample, isn't it?

Didn't they allow using oauth in custom harnesses for personal use (e.g. pi.dev)?

This is trivially circumventable by changing the system prompt (they string match against a blacklist).