Fix issue #5637: [Bug]: Incorrectly interpreting a Python error as a success message

openhands/events/observation/commands.py

@@ -40,15 +40,23 @@ class IPythonRunCellObservation(Observation):
 
     @property
     def error(self) -> bool:
-        return False  # IPython cells do not return exit codes
+        # Check for common error indicators in IPython output
+        error_indicators = [
+            'ERROR:',
+            'Error:',
+            'Exception:',
+            'Parameter `',
+            'is required for command:',
+        ]
+        return any(indicator in self.content for indicator in error_indicators)
 
     @property
     def message(self) -> str:
         return 'Code executed in IPython cell.'
 
     @property
     def success(self) -> bool:
-        return True  # IPython cells are always considered successful
+        return not self.error
 
     def __str__(self) -> str:
         return f'**IPythonRunCellObservation**\n{self.content}'

tests/unit/test_observation_serialization.py

@@ -40,6 +40,33 @@ def serialization_deserialization(
 
 
 # Additional tests for various observation subclasses can be included here
+def test_ipython_error_detection():
+    from openhands.events.observation import IPythonRunCellObservation
+
+    # Test error detection for various error patterns
+    error_cases = [
+        'ERROR: Something went wrong',
+        'Error: Invalid syntax',
+        'Exception: Division by zero',
+        'Parameter `old_str` is required for command: str_replace',
+    ]
+    for error_content in error_cases:
+        obs = IPythonRunCellObservation(content=error_content, code='print("test")')
+        serialized = event_to_dict(obs)
+        assert (
+            serialized['success'] is False
+        ), f'Failed to detect error in: {error_content}'
+        assert obs.error is True, f'Failed to detect error in: {error_content}'
+
+    # Test success case
+    obs = IPythonRunCellObservation(
+        content='Hello World!', code='print("Hello World!")'
+    )
+    serialized = event_to_dict(obs)
+    assert serialized['success'] is True, 'Failed to detect success'
+    assert obs.error is False, 'Failed to detect success'
+
+
 def test_success_field_serialization():
     # Test success=True
     obs = CmdOutputObservation(