diff --git a/backend/workflow_executor.py b/backend/workflow_executor.py
index 2d78b68..1aa67d5 100644
--- a/backend/workflow_executor.py
+++ b/backend/workflow_executor.py
@@ -410,17 +410,33 @@ def execute_logic_node(
             )
 
         # Handle both serialization formats:
-        # UI format: condition = {operands: [...], operator: "and"}
-        # Expected format: condition = {expression: {operands: [...], operator: "and"}}
+        # UI format: condition = {operands: [...], operator: "and"}  (dict or LogicExpression)
+        # Legacy format: condition = {expression: {operands: [...], operator: "and"}}  (Condition object)
         expression = None
 
-        if hasattr(node.condition, 'operator') and hasattr(node.condition, 'operands'):
-            # UI format (direct) - check that operator is not None
-            if node.condition.operator is not None:
+        # Convert to dict if it's a Pydantic model
+        condition_dict = node.condition
+        if hasattr(node.condition, 'model_dump'):
+            condition_dict = node.condition.model_dump()
+        elif hasattr(node.condition, 'dict'):
+            condition_dict = node.condition.dict()
+
+        # Check if it's a dict
+        if isinstance(condition_dict, dict):
+            # UI format: direct LogicExpression
+            if 'operator' in condition_dict and 'operands' in condition_dict:
+                from workflow_models import LogicExpression
+                expression = LogicExpression(**condition_dict)
+            # Legacy format: wrapped in Condition
+            elif 'expression' in condition_dict and condition_dict['expression'] is not None:
+                from workflow_models import LogicExpression
+                expression = LogicExpression(**condition_dict['expression'])
+        # Pydantic object
+        else:
+            if hasattr(node.condition, 'operator') and hasattr(node.condition, 'operands'):
                 expression = node.condition
-        elif hasattr(node.condition, 'expression') and node.condition.expression is not None:
-            # Expected format (wrapped) - check that expression is not None
-            expression = node.condition.expression
+            elif hasattr(node.condition, 'expression') and node.condition.expression is not None:
+                expression = node.condition.expression
 
         if expression is None:
             error_msg = f"Logic node {node.id} has invalid or empty condition (operator/operands/expression is None or missing)"
diff --git a/backend/workflow_models.py b/backend/workflow_models.py
index 5b92126..e98c0fe 100644
--- a/backend/workflow_models.py
+++ b/backend/workflow_models.py
@@ -195,7 +195,8 @@ class WorkflowNode(BaseModel):
     question_augmentations: Optional[List[QuestionAugmentation]] = Field(None, description="Fragenergänzungen (knotengebunden, überschreiben Prompt-Defaults)")
 
     # LOGIC-Knoten
-    condition: Optional[Condition] = Field(None, description="Bedingung für Pfad-Routing")
+    # Support both formats: direct LogicExpression (UI) or wrapped in Condition (legacy)
+    condition: Optional[Any] = Field(None, description="Bedingung für Pfad-Routing (LogicExpression or Condition)")
     fallback: Optional[FallbackConfig] = Field(None, description="Fallback-Konfiguration")
 
     # JOIN-Knoten (Phase 4)