I just realized that claude has also support App Attest for months [1]. Not sure if that is being used widely. Firebase was the most practicle option to call llms directly from ios apps without having fancy setups. I am surprised Anthropic not promoting this more.

[1] https://github.com/anthropics/ClaudeForFoundationModels#auth...

This was the first time I've encountered App Attest and it seems like a pretty solid solution to the problem of having to trust that a request from someone else's device is in fact originating from your own app rather than an extracted key of some form.