diff --git a/api/core/tools/tool_manager.py b/api/core/tools/tool_manager.py
index f286466de0..71c237c7f7 100644
--- a/api/core/tools/tool_manager.py
+++ b/api/core/tools/tool_manager.py
@@ -1011,7 +1011,9 @@ class ToolManager:
                         if variable is None:
                             raise ToolParameterError(f"Variable {tool_input.value} does not exist")
                         parameter_value = variable.value
-                    elif tool_input.type in {"mixed", "constant"}:
+                    elif tool_input.type == "constant":
+                        parameter_value = tool_input.value
+                    elif tool_input.type == "mixed":
                         segment_group = variable_pool.convert_template(str(tool_input.value))
                         parameter_value = segment_group.text
                     else:
diff --git a/api/core/workflow/nodes/tool/entities.py b/api/core/workflow/nodes/tool/entities.py
index f0a44d919b..4f47fb1efc 100644
--- a/api/core/workflow/nodes/tool/entities.py
+++ b/api/core/workflow/nodes/tool/entities.py
@@ -54,7 +54,7 @@ class ToolNodeData(BaseNodeData, ToolEntity):
                 for val in value:
                     if not isinstance(val, str):
                         raise ValueError("value must be a list of strings")
-            elif typ == "constant" and not isinstance(value, str | int | float | bool):
+            elif typ == "constant" and not isinstance(value, str | int | float | bool | dict):
                 raise ValueError("value must be a string, int, float, or bool")
             return typ
 
diff --git a/web/app/components/workflow/nodes/_base/components/form-input-item.tsx b/web/app/components/workflow/nodes/_base/components/form-input-item.tsx
index 316a5c9819..1efa8aab02 100644
--- a/web/app/components/workflow/nodes/_base/components/form-input-item.tsx
+++ b/web/app/components/workflow/nodes/_base/components/form-input-item.tsx
@@ -164,7 +164,7 @@ const FormInputItem: FC<Props> = ({
       ...value,
       [variable]: {
         ...varInput,
-        ...newValue,
+        value: newValue,
       },
     })
   }
@@ -242,7 +242,7 @@ const FormInputItem: FC<Props> = ({
         <AppSelector
           disabled={readOnly}
           scope={scope || 'all'}
-          value={varInput as any}
+          value={varInput?.value}
           onSelect={handleAppOrModelSelect}
         />
       )}
@@ -251,7 +251,7 @@ const FormInputItem: FC<Props> = ({
           popupClassName='!w-[387px]'
           isAdvancedMode
           isInWorkflow
-          value={varInput}
+          value={varInput?.value}
           setModel={handleAppOrModelSelect}
           readonly={readOnly}
           scope={scope}