Incorrectly identifying missing API key

I'm using Vertex - I assume it's that. I would expect to _not_ see this error as I'm able to communicate with Claude successfully.

Also, it would be great if this error could display when your authentication to GCP (Vertex?) is also invalid/expired, which usually forces a sign-in every 24 hours.

<img width="798" alt="Image" src="https://github.com/user-attachments/assets/d1d80617-0454-48f9-aefd-ee0f60590083" />