Closes#204. PR #198 wired push_sender=PushNotificationSender() into
DefaultRequestHandler to satisfy #175's push-notification capability,
but PushNotificationSender in a2a-sdk is an abstract base class and
cannot be instantiated. Every workspace container crashed on startup
with TypeError.
Reverted to DefaultRequestHandler's defaults. The pushNotifications
capability still appears in AgentCard.capabilities (advertised to A2A
clients) but actual implementation of the sender is deferred to a
Phase-H follow-up that subclasses PushNotificationSender properly.
Existing pytest suite unchanged (the crash was only at runtime on
main.py import, which no existing test exercises directly).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
#173 — implement cancel() in LangGraphA2AExecutor: emits
TaskStatusUpdateEvent(state=canceled, final=True) so clients see the
state transition rather than silence. Removes pragma: no cover.
Test: test_cancel_emits_canceled_event.
#174 — add stateTransitionHistory=True to AgentCapabilities in main.py
so microsoft/agent-framework clients know they can request full task
history via the A2A protocol.
#175 — wire InMemoryPushNotificationConfigStore and PushNotificationSender
into DefaultRequestHandler so the advertised pushNotifications capability
is backed by a real store. Both classes live in a2a.server.tasks (a2a-sdk
0.3.25); import confirmed by probe.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>