Make end call tool can be cancelled

backend/services/brains/workflow_brain.py

@@ -603,15 +603,12 @@ class WorkflowBrain(BaseBrain):
             self._state.consume_user_turn()
             if self._engine.node_type(self._state.current_node_id) == "agent":
                 self._state.status = WorkflowStatus.WAITING_USER
-        if (
-            self._waiting_for_generated_end_speech
-            and self._runtime is not None
-            and self._runtime.call_end.ending
-        ):
+        if self._waiting_for_generated_end_speech:
             self._waiting_for_generated_end_speech = False
-            await self._runtime.call_end.finish_after_current_speech(
-                has_text=bool(content.strip()) and not interrupted
-            )
+            if self._runtime is not None and self._runtime.call_end.ending:
+                await self._runtime.call_end.finish_after_current_speech(
+                    has_text=bool(content.strip()) and not interrupted
+                )
 
     async def on_realtime_user_speech_started(self) -> None:
         if self._realtime_controller is not None:
@@ -1090,13 +1087,19 @@ class WorkflowBrain(BaseBrain):
         message_type = str(config.get("message_type") or "none")
         custom_message = str(config.get("custom_message") or "").strip()
         capture_reason = bool(config.get("capture_reason", True))
+        allow_end_interruption = bool(
+            config.get("allow_end_interruption", False)
+        )
 
         async def handler(args, _flow_manager):
             reason = str((args or {}).get("reason") or "end_conversation").strip()
             uses_custom_message = message_type == "custom" and bool(custom_message)
             self._waiting_for_generated_end_speech = not uses_custom_message
             runtime = self._require_runtime()
-            runtime.call_end.begin(reason)
+            runtime.call_end.begin(
+                reason,
+                interruptible=allow_end_interruption,
+            )
             if uses_custom_message:
                 await self._queue_visible_speech(
                     custom_message,