Insufficient credit error has the same error code as bad requests

[dandv]

When calling the Messages API with a valid request but insufficient credit, the API returns status code 400 and the message

Your credit balance is too low to access the Anthropic API. Please go to Plans & Billing to upgrade or purchase credits.

Would it be more appropriate to return 402 Payment required, and reserve 400 for actually malformed requests?

[localden]

Thanks for the report. The API now returns a distinct billing error type, and the SDK surfaces it as BillingError. Closing as resolved.