Client-generated operation ID - groups related work across multiple agents
Agent ID - which agent is handling this
OptionalcontextContext ID from server - created by agent on first response
OptionaltaskTask ID from server - only present for async operations
Task/tool name
Event timestamp
New status
OptionalpreviousPrevious status (if applicable)
OptionalresultResult data (for completed)
OptionalerrorError details (for failed)
Task status update event - emitted on status changes