This page outlines the union type for real-time conversation updates and the object types it can include.

ConversationUpdateOneOf

assistantMessageSent
ChatMessage
A complete message sent by the assistant. See ChatMessage.
assistantResponseDiff
ChatMessageDiff
A streaming diff update for an assistant’s response in progress. See ChatMessageDiff.
assistantResponseCancelled
Boolean
Indicates whether the assistant’s response was cancelled.

Additional Resources