Optional cause: unknownReadonly providerProvider that failed to initialize.
Optional Readonly httpHTTP status of the underlying failure, when it had one.
Optional Readonly causeThe error the provider threw during initialization, when there was one.
Thrown by createProviderManager when the requested provider did not initialize: a rejected or revoked API key (the provider's model listing answers 401), an unreachable endpoint, or a provider id the manager does not know. The fallback walker treats it as retryable, so a primary whose key stopped working fails over like one that answers 401 on the call.
httpStatusrepeats the cause's HTTP status when it has one, which the provider health registry uses to pick its cooldown.