OptionaldataOptionaldurationOptionalerrorThe provider's own message when success is false. errorInfo has the classification.
OptionalerrorStructured error when success is false.
OptionalfallbackTrue when a fallback provider answered.
OptionalfinishOptionalhandedSet when a handoff tool fired: the agent that produced this answer. Its own handedOffTo continues the chain.
OptionalmodelOptionalobjectThe parsed (and validated) answer when schema was given.
OptionalproviderOptionalreasoningThe model's thinking, when it exposed any. Never part of data.
OptionalrequestProvider request id header, when sent.
OptionalretryRetries spent before this answer.
OptionalstepsThe rounds the factory ran before this answer, when maxSteps > 1 and at least one tool ran.
OptionaltoolCalls the model wants made; finishReason is 'tool_calls'. Absent when there are none.
Optionalusage
Wall time of the whole call, including retries and fallback.