fix: improve stuck detection in UI mode

- Add UI mode awareness to stuck detection
- Only consider history after last user message in UI mode
- Keep existing behavior in headless mode
- Add comprehensive tests for both modes

Fix: #5480

openhands/controller/agent_controller.py

@@ -902,17 +902,20 @@ def _apply_conversation_window(self, events: list[Event]) -> list[Event]:
 
         return kept_events
 
-    def _is_stuck(self) -> bool:
+    def _is_stuck(self, ui_mode: bool | None = None) -> bool:
         """Checks if the agent or its delegate is stuck in a loop.
 
+        Args:
+            ui_mode: Optional override for UI mode. If not provided, uses not self.headless_mode.
+
         Returns:
             bool: True if the agent is stuck, False otherwise.
         """
         # check if delegate stuck
-        if self.delegate and self.delegate._is_stuck():
+        if self.delegate and self.delegate._is_stuck(ui_mode):
             return True
 
-        return self._stuck_detector.is_stuck()
+        return self._stuck_detector.is_stuck(ui_mode if ui_mode is not None else not self.headless_mode)
 
     def __repr__(self):
         return (

openhands/controller/stuck.py

@@ -24,16 +24,26 @@ class StuckDetector:
     def __init__(self, state: State):
         self.state = state
 
-    def is_stuck(self):
-        # filter out MessageAction with source='user' from history
+    def is_stuck(self, ui_mode: bool = False):
+        if ui_mode:
+            # In UI mode, only look at history after the last user message
+            last_user_msg_idx = -1
+            for i, event in enumerate(self.state.history):
+                if isinstance(event, MessageAction) and event.source == EventSource.USER:
+                    last_user_msg_idx = i
+
+            history_to_check = self.state.history[last_user_msg_idx + 1:]
+        else:
+            # In headless mode, look at all history
+            history_to_check = self.state.history
+
+        # Filter out user messages and null events
         filtered_history = [
             event
-            for event in self.state.history
+            for event in history_to_check
             if not (
                 (isinstance(event, MessageAction) and event.source == EventSource.USER)
-                or
-                # there might be some NullAction or NullObservation in the history at least for now
-                isinstance(event, (NullAction, NullObservation))
+                or isinstance(event, (NullAction, NullObservation))
             )
         ]
 

tests/unit/test_is_stuck.py

@@ -112,7 +112,53 @@ def test_history_too_short(self, stuck_detector: StuckDetector):
         # cmd_observation._cause = cmd_action._id
         state.history.append(cmd_observation)
 
-        assert stuck_detector.is_stuck() is False
+        assert stuck_detector.is_stuck(ui_mode=False) is False
+        assert stuck_detector.is_stuck(ui_mode=True) is False
+
+    def test_ui_mode_resets_after_user_message(self, stuck_detector: StuckDetector):
+        state = stuck_detector.state
+
+        # First add some actions that would be stuck in non-UI mode
+        for i in range(4):
+            cmd_action = CmdRunAction(command='ls')
+            cmd_action._id = i
+            state.history.append(cmd_action)
+            cmd_observation = CmdOutputObservation(content='', command='ls', command_id=i)
+            cmd_observation._cause = cmd_action._id
+            state.history.append(cmd_observation)
+
+        # In non-UI mode, this should be stuck
+        assert stuck_detector.is_stuck(ui_mode=False) is True
+
+        # Add a user message
+        message_action = MessageAction(content='Hello', wait_for_response=False)
+        message_action._source = EventSource.USER
+        state.history.append(message_action)
+
+        # In UI mode, this should not be stuck because we ignore history before user message
+        assert stuck_detector.is_stuck(ui_mode=True) is False
+
+        # Add two more identical actions - still not stuck because we need at least 3
+        for i in range(2):
+            cmd_action = CmdRunAction(command='ls')
+            cmd_action._id = i + 4
+            state.history.append(cmd_action)
+            cmd_observation = CmdOutputObservation(content='', command='ls', command_id=i + 4)
+            cmd_observation._cause = cmd_action._id
+            state.history.append(cmd_observation)
+
+        assert stuck_detector.is_stuck(ui_mode=True) is False
+
+        # Add two more identical actions - now it should be stuck
+        for i in range(2):
+            cmd_action = CmdRunAction(command='ls')
+            cmd_action._id = i + 6
+            state.history.append(cmd_action)
+            cmd_observation = CmdOutputObservation(content='', command='ls', command_id=i + 6)
+            cmd_observation._cause = cmd_action._id
+            state.history.append(cmd_observation)
+
+        assert stuck_detector.is_stuck(ui_mode=True) is True
 
     def test_is_stuck_repeating_action_observation(self, stuck_detector: StuckDetector):
         state = stuck_detector.state
@@ -148,7 +194,7 @@ def test_is_stuck_repeating_action_observation(self, stuck_detector: StuckDetect
         state.history.append(message_null_observation)
         # 8 events
 
-        assert stuck_detector.is_stuck() is False
+        assert stuck_detector.is_stuck(ui_mode=False) is False
 
         cmd_action_3 = CmdRunAction(command='ls')
         cmd_action_3._id = 3
@@ -159,7 +205,7 @@ def test_is_stuck_repeating_action_observation(self, stuck_detector: StuckDetect
         # 10 events
 
         assert len(state.history) == 10
-        assert stuck_detector.is_stuck() is False
+        assert stuck_detector.is_stuck(ui_mode=False) is False
 
         cmd_action_4 = CmdRunAction(command='ls')
         cmd_action_4._id = 4
@@ -172,7 +218,7 @@ def test_is_stuck_repeating_action_observation(self, stuck_detector: StuckDetect
         assert len(state.history) == 12
 
         with patch('logging.Logger.warning') as mock_warning:
-            assert stuck_detector.is_stuck() is True
+            assert stuck_detector.is_stuck(ui_mode=False) is True
             mock_warning.assert_called_once_with('Action, Observation loop detected')
 
     def test_is_stuck_repeating_action_error(self, stuck_detector: StuckDetector):
@@ -224,7 +270,7 @@ def test_is_stuck_repeating_action_error(self, stuck_detector: StuckDetector):
         # 12 events
 
         with patch('logging.Logger.warning') as mock_warning:
-            assert stuck_detector.is_stuck() is True
+            assert stuck_detector.is_stuck(ui_mode=False) is True
             mock_warning.assert_called_once_with(
                 'Action, ErrorObservation loop detected'
             )
@@ -238,7 +284,7 @@ def test_is_stuck_invalid_syntax_error(self, stuck_detector: StuckDetector):
         )
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is True
+            assert stuck_detector.is_stuck(ui_mode=False) is True
 
     def test_is_not_stuck_invalid_syntax_error_random_lines(
         self, stuck_detector: StuckDetector
@@ -251,7 +297,7 @@ def test_is_not_stuck_invalid_syntax_error_random_lines(
         )
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is False
+            assert stuck_detector.is_stuck(ui_mode=False) is False
 
     def test_is_not_stuck_invalid_syntax_error_only_three_incidents(
         self, stuck_detector: StuckDetector
@@ -265,7 +311,7 @@ def test_is_not_stuck_invalid_syntax_error_only_three_incidents(
         )
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is False
+            assert stuck_detector.is_stuck(ui_mode=False) is False
 
     def test_is_stuck_incomplete_input_error(self, stuck_detector: StuckDetector):
         state = stuck_detector.state
@@ -276,7 +322,7 @@ def test_is_stuck_incomplete_input_error(self, stuck_detector: StuckDetector):
         )
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is True
+            assert stuck_detector.is_stuck(ui_mode=False) is True
 
     def test_is_not_stuck_incomplete_input_error(self, stuck_detector: StuckDetector):
         state = stuck_detector.state
@@ -287,7 +333,7 @@ def test_is_not_stuck_incomplete_input_error(self, stuck_detector: StuckDetector
         )
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is False
+            assert stuck_detector.is_stuck(ui_mode=False) is False
 
     def test_is_not_stuck_ipython_unterminated_string_error_random_lines(
         self, stuck_detector: StuckDetector
@@ -296,7 +342,7 @@ def test_is_not_stuck_ipython_unterminated_string_error_random_lines(
         self._impl_unterminated_string_error_events(state, random_line=True)
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is False
+            assert stuck_detector.is_stuck(ui_mode=False) is False
 
     def test_is_not_stuck_ipython_unterminated_string_error_only_three_incidents(
         self, stuck_detector: StuckDetector
@@ -307,7 +353,7 @@ def test_is_not_stuck_ipython_unterminated_string_error_only_three_incidents(
         )
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is False
+            assert stuck_detector.is_stuck(ui_mode=False) is False
 
     def test_is_stuck_ipython_unterminated_string_error(
         self, stuck_detector: StuckDetector
@@ -316,7 +362,7 @@ def test_is_stuck_ipython_unterminated_string_error(
         self._impl_unterminated_string_error_events(state, random_line=False)
 
         with patch('logging.Logger.warning'):
-            assert stuck_detector.is_stuck() is True
+            assert stuck_detector.is_stuck(ui_mode=False) is True
 
     def test_is_not_stuck_ipython_syntax_error_not_at_end(
         self, stuck_detector: StuckDetector
@@ -361,7 +407,7 @@ def test_is_not_stuck_ipython_syntax_error_not_at_end(
         state.history.append(ipython_observation_4)
 
         with patch('logging.Logger.warning') as mock_warning:
-            assert stuck_detector.is_stuck() is False
+            assert stuck_detector.is_stuck(ui_mode=False) is False
             mock_warning.assert_not_called()
 
     def test_is_stuck_repeating_action_observation_pattern(
@@ -430,7 +476,7 @@ def test_is_stuck_repeating_action_observation_pattern(
         state.history.append(read_observation_3)
 
         with patch('logging.Logger.warning') as mock_warning:
-            assert stuck_detector.is_stuck() is True
+            assert stuck_detector.is_stuck(ui_mode=False) is True
             mock_warning.assert_called_once_with('Action, Observation pattern detected')
 
     def test_is_stuck_not_stuck(self, stuck_detector: StuckDetector):
@@ -496,7 +542,7 @@ def test_is_stuck_not_stuck(self, stuck_detector: StuckDetector):
         # read_observation_3._cause = read_action_3._id
         state.history.append(read_observation_3)
 
-        assert stuck_detector.is_stuck() is False
+        assert stuck_detector.is_stuck(ui_mode=False) is False
 
     def test_is_stuck_monologue(self, stuck_detector):
         state = stuck_detector.state
@@ -526,7 +572,7 @@ def test_is_stuck_monologue(self, stuck_detector):
         message_action_6._source = EventSource.AGENT
         state.history.append(message_action_6)
 
-        assert stuck_detector.is_stuck()
+        assert stuck_detector.is_stuck(ui_mode=False)
 
         # Add an observation event between the repeated message actions
         cmd_output_observation = CmdOutputObservation(
@@ -546,7 +592,7 @@ def test_is_stuck_monologue(self, stuck_detector):
         state.history.append(message_action_8)
 
         with patch('logging.Logger.warning'):
-            assert not stuck_detector.is_stuck()
+            assert not stuck_detector.is_stuck(ui_mode=False)
 
 
 class TestAgentController:
@@ -563,4 +609,4 @@ def controller(self):
     def test_is_stuck_delegate_stuck(self, controller: AgentController):
         controller.delegate = Mock()
         controller.delegate._is_stuck.return_value = True
-        assert controller._is_stuck() is True
+        assert controller._is_stuck(ui_mode=False) is True