Type Alias: AiFailureKind

type AiFailureKind = 
  | "request"
  | "vendor"
  | "network"
  | "timeout"
  | "refusal"
  | "output"
  | "unsupported";

Why a request has no answer (AiError.kind): request (the host refused it), vendor (an error status), network, timeout, refusal (the model refused), output (an answer outside what was asked) or unsupported (the model cannot do what was asked).