diff --git a/mistral/engine/task_handler.py b/mistral/engine/task_handler.py
index c5272c92d..562d1215c 100644
--- a/mistral/engine/task_handler.py
+++ b/mistral/engine/task_handler.py
@@ -106,9 +106,9 @@ def _on_action_complete(action_ex):
     except exc.MistralException as e:
         wf_ex = task_ex.workflow_execution
 
-        msg = ("Failed to handle action completion [wf=%s, task=%s,"
-               " action=%s]: %s\n%s" %
-               (wf_ex.name, task_ex.name, action_ex.name, e, tb.format_exc()))
+        msg = ("Failed to handle action completion [error=%s, wf=%s, task=%s,"
+               " action=%s]:\n%s" %
+               (e, wf_ex.name, task_ex.name, action_ex.name, tb.format_exc()))
 
         LOG.error(msg)
 
@@ -184,8 +184,8 @@ def complete_task(task_ex, state, state_info):
         wf_ex = task_ex.workflow_execution
 
         msg = (
-            "Failed to complete task [wf=%s, task=%s]: %s\n%s" %
-            (wf_ex, task_ex.name, e, tb.format_exc())
+            "Failed to complete task [error=%s, wf=%s, task=%s]:\n%s" %
+            (e, wf_ex, task_ex.name, tb.format_exc())
         )
 
         LOG.error(msg)
diff --git a/mistral/tests/unit/engine/test_error_handling.py b/mistral/tests/unit/engine/test_error_handling.py
index 193c3c47f..3a93c47ba 100644
--- a/mistral/tests/unit/engine/test_error_handling.py
+++ b/mistral/tests/unit/engine/test_error_handling.py
@@ -474,3 +474,67 @@ class ErrorHandlingEngineTest(base.EngineTestCase):
         self.assertIsNotNone(state_info)
         self.assertTrue(state_info.find('error=') > 0)
         self.assertTrue(state_info.find('error=') < state_info.find('wf='))
+
+    def test_error_message_format_on_action_complete(self):
+        wf_text = """
+        version: '2.0'
+
+        wf:
+          tasks:
+            task1:
+              action: std.noop
+              publish:
+                my_var: <% invalid_yaql_function() %>
+        """
+
+        wf_service.create_workflows(wf_text)
+
+        wf_ex = self.engine.start_workflow('wf', {})
+
+        self.await_workflow_error(wf_ex.id)
+
+        with db_api.transaction():
+            wf_ex = db_api.get_workflow_execution(wf_ex.id)
+
+            task_ex = wf_ex.task_executions[0]
+
+        state_info = task_ex.state_info
+
+        print(state_info)
+
+        self.assertIsNotNone(state_info)
+        self.assertTrue(state_info.find('error=') > 0)
+        self.assertTrue(state_info.find('error=') < state_info.find('wf='))
+
+    def test_error_message_format_complete_task(self):
+        wf_text = """
+        version: '2.0'
+
+        wf:
+          tasks:
+            task1:
+              action: std.noop
+              wait-after: 1
+              on-success:
+                - task2: <% invalid_yaql_function() %>
+
+            task2:
+              action: std.noop
+        """
+
+        wf_service.create_workflows(wf_text)
+
+        wf_ex = self.engine.start_workflow('wf', {})
+
+        self.await_workflow_error(wf_ex.id)
+
+        with db_api.transaction():
+            wf_ex = db_api.get_workflow_execution(wf_ex.id)
+
+            task_ex = wf_ex.task_executions[0]
+
+        state_info = task_ex.state_info
+
+        self.assertIsNotNone(state_info)
+        self.assertTrue(state_info.find('error=') > 0)
+        self.assertTrue(state_info.find('error=') < state_info.find('wf='))
diff --git a/mistral/tests/unit/engine/test_execution_fields_size_limitation.py b/mistral/tests/unit/engine/test_execution_fields_size_limitation.py
index 7c6c48c64..68de8996e 100644
--- a/mistral/tests/unit/engine/test_execution_fields_size_limitation.py
+++ b/mistral/tests/unit/engine/test_execution_fields_size_limitation.py
@@ -195,10 +195,12 @@ class ExecutionFieldsSizeLimitTest(base.EngineTestCase):
         wf_ex = db_api.get_workflow_execution(wf_ex.id)
 
         self.assertIn(
-            'Failed to handle action completion [wf=wf, task=task1',
+            'Failed to handle action completion [error=Size of',
             wf_ex.state_info
         )
 
+        self.assertIn('wf=wf, task=task1', wf_ex.state_info)
+
         task_ex = self._assert_single_item(wf_ex.task_executions, name='task1')
 
         self.assertIn(