Package org.a2aproject.sdk.spec

Interface Event

All Known Subinterfaces:
StreamingEventKind
All Known Implementing Classes:
A2AError, A2AProtocolError, ContentTypeNotSupportedError, ExtendedAgentCardNotConfiguredError, ExtensionSupportRequiredError, InternalError, InvalidAgentResponseError, InvalidParamsError, InvalidRequestError, JSONParseError, Message, MethodNotFoundError, PushNotificationNotSupportedError, QueueClosedEvent, Task, TaskArtifactUpdateEvent, TaskNotCancelableError, TaskNotFoundError, TaskStatusUpdateEvent, UnsupportedOperationError, VersionNotSupportedError
public interface Event
Marker interface for all event types in the A2A Protocol.

Events are the fundamental communication mechanism for agent task execution and state updates. They enable both synchronous request-response patterns and asynchronous streaming updates.

The Event hierarchy includes:

  • EventKind - Events that can be returned from non-streaming operations
  • StreamingEventKind - Events that can be emitted during streaming responses
  • UpdateEvent - Incremental update events for task progress

Common event types include:

See Also: