fix: interrupt message output before tool result

backend/tests/test_client_tools.py

@@ -138,6 +138,51 @@ class ClientToolExecutorTests(unittest.IsolatedAsyncioTestCase):
 
 
 class ClientToolBrokerTests(unittest.IsolatedAsyncioTestCase):
+    async def test_interrupts_before_resolving_configured_result(self):
+        broker = ClientToolBroker()
+        outbound = []
+        observed_future_states = []
+
+        async def push_frame(frame, direction=FrameDirection.DOWNSTREAM):
+            outbound.append((frame, direction))
+
+        async def broadcast_interruption():
+            observed_future_states.append(
+                [pending.future.done() for pending in broker._pending.values()]
+            )
+
+        broker.push_frame = push_frame
+        broker.broadcast_interruption = broadcast_interruption
+        call = asyncio.create_task(
+            broker.call(
+                "show_message",
+                {},
+                timeout_seconds=1,
+                response_wait_mode="session",
+                interrupt_on_result=True,
+            )
+        )
+        await asyncio.sleep(0)
+        message = outbound[0][0].message
+
+        await broker.process_frame(
+            InputTransportMessageFrame(
+                message={
+                    "type": "client-tool-result",
+                    "tool_call_id": message["tool_call_id"],
+                    "status": "ok",
+                    "data": {"action": "confirmed"},
+                }
+            ),
+            FrameDirection.DOWNSTREAM,
+        )
+
+        self.assertEqual(observed_future_states, [[False]])
+        self.assertEqual(
+            await call,
+            {"status": "ok", "data": {"action": "confirmed"}},
+        )
+
     async def test_correlates_result_and_times_out(self):
         broker = ClientToolBroker()
         outbound = []