Save complete trajectory in presence of history truncation

openhands/controller/agent_controller.py

@@ -50,7 +50,7 @@
     NullObservation,
     Observation,
 )
-from openhands.events.serialization.event import truncate_content
+from openhands.events.serialization.event import event_to_trajectory, truncate_content
 from openhands.llm.llm import LLM
 
 # note: RESUME is only available on web GUI
@@ -687,22 +687,7 @@ async def _step(self) -> None:
                     or 'prompt is too long' in error_str
                     or isinstance(e, ContextWindowExceededError)
                 ):
-                    # When context window is exceeded, keep roughly half of agent interactions
-                    self.state.history = self._apply_conversation_window(
-                        self.state.history
-                    )
-
-                    # Save the ID of the first event in our truncated history for future reloading
-                    if self.state.history:
-                        self.state.start_id = self.state.history[0].id
-
-                    # Add an error event to trigger another step by the agent
-                    self.event_stream.add_event(
-                        AgentCondensationObservation(
-                            content='Trimming prompt to meet context window limitations'
-                        ),
-                        EventSource.AGENT,
-                    )
+                    self._handle_long_context_error()
                     return
                 raise e
 
@@ -831,6 +816,10 @@ def set_initial_state(
         # Always load from the event stream to avoid losing history
         self._init_history()
 
+    def get_trajectory(self) -> list[dict]:
+        events = self.event_stream.get_events()
+        return [event_to_trajectory(event) for event in events]
+
     def _init_history(self) -> None:
         """Initializes the agent's history from the event stream.
 
@@ -956,6 +945,22 @@ def _init_history(self) -> None:
         # make sure history is in sync
         self.state.start_id = start_id
 
+    def _handle_long_context_error(self) -> None:
+        # When context window is exceeded, keep roughly half of agent interactions
+        self.state.history = self._apply_conversation_window(self.state.history)
+
+        # Save the ID of the first event in our truncated history for future reloading
+        if self.state.history:
+            self.state.start_id = self.state.history[0].id
+
+        # Add an error event to trigger another step by the agent
+        self.event_stream.add_event(
+            AgentCondensationObservation(
+                content='Trimming prompt to meet context window limitations'
+            ),
+            EventSource.AGENT,
+        )
+
     def _apply_conversation_window(self, events: list[Event]) -> list[Event]:
         """Cuts history roughly in half when context window is exceeded, preserving action-observation pairs
         and ensuring the first user message is always included.

openhands/core/main.py

@@ -28,7 +28,6 @@
 from openhands.events.event import Event
 from openhands.events.observation import AgentStateChangedObservation
 from openhands.events.serialization import event_from_dict
-from openhands.events.serialization.event import event_to_trajectory
 from openhands.runtime.base import Runtime
 
 
@@ -204,7 +203,7 @@ def on_event(event: Event):
         else:
             file_path = config.save_trajectory_path
         os.makedirs(os.path.dirname(file_path), exist_ok=True)
-        histories = [event_to_trajectory(event) for event in state.history]
+        histories = controller.get_trajectory()
         with open(file_path, 'w') as f:
             json.dump(histories, f)
 

openhands/server/routes/trajectory.py

@@ -22,9 +22,7 @@ async def get_trajectory(request: Request):
         events.
     """
     try:
-        async_stream = AsyncEventStreamWrapper(
-            request.state.conversation.event_stream, filter_hidden=True
-        )
+        async_stream = AsyncEventStreamWrapper(request.state.conversation.event_stream)
         trajectory = []
         async for event in async_stream:
             trajectory.append(event_to_trajectory(event))

tests/unit/test_truncation.py

@@ -72,6 +72,50 @@ def test_apply_conversation_window_basic(self, mock_event_stream, mock_agent):
             if isinstance(event, CmdOutputObservation):
                 assert any(e._id == event._cause for e in truncated[: i + 1])
 
+    def test_truncation_does_not_impact_trajectory(self, mock_event_stream, mock_agent):
+        controller = AgentController(
+            agent=mock_agent,
+            event_stream=mock_event_stream,
+            max_iterations=10,
+            sid='test_truncation',
+            confirmation_mode=False,
+            headless_mode=True,
+        )
+
+        # Create a sequence of events with IDs
+        first_msg = MessageAction(content='Hello, start task', wait_for_response=False)
+        first_msg._source = EventSource.USER
+        first_msg._id = 1
+
+        pairs = 10
+        history_len = 1 + 2 * pairs
+        events = [first_msg]
+        for i in range(pairs):
+            cmd = CmdRunAction(command=f'cmd{i}')
+            cmd._id = i + 2
+            obs = CmdOutputObservation(
+                command=f'cmd{i}', content=f'output{i}', command_id=cmd._id
+            )
+            obs._cause = cmd._id
+            events.extend([cmd, obs])
+
+        # patch events to history for testing purpose
+        controller.state.history = events
+
+        # Update mock event stream
+        mock_event_stream.get_events.return_value = controller.state.history
+
+        assert len(controller.state.history) == history_len
+
+        # Force apply truncation
+        controller._handle_long_context_error()
+
+        # Check that the history has been truncated
+        assert len(controller.state.history) == 13 < history_len
+
+        assert len(controller.event_stream.get_events()) == history_len
+        assert len(controller.get_trajectory()) == history_len
+
     def test_context_window_exceeded_handling(self, mock_event_stream, mock_agent):
         controller = AgentController(
             agent=mock_agent,