When an Anthropic Claude Pro/Max OAuth subscription hits the "out of extra
usage" 400 (now classified as billing), surface actionable guidance pointing
at claude.ai/settings/usage and the cycle-reset option instead of the generic
"add credits with that provider" line — which does not apply to a
subscription. Folds in the UX from #40073 (@harsh-matchmyflight) without the
extra FailoverReason enum; the billing reclass already provides the recovery
behavior.
