diff --git a/comfyui_to_python.py b/comfyui_to_python.py
index 6eec402..d53b7ef 100644
--- a/comfyui_to_python.py
+++ b/comfyui_to_python.py
@@ -194,6 +194,15 @@ class CodeGenerator:
         self.node_class_mappings = node_class_mappings
         self.base_node_class_mappings = base_node_class_mappings
 
+    @staticmethod
+    def sanitize_node_id(node_id: str) -> str:
+        """Convert node IDs into variable-safe tokens without collapsing separators."""
+        sanitized = re.sub(r"[^a-z0-9_]", "_", str(node_id).lower().strip())
+        sanitized = re.sub(r"_+", "_", sanitized).strip("_")
+        if not sanitized:
+            sanitized = "node"
+        return sanitized
+
     def generate_workflow(
         self,
         load_order: List,
@@ -284,7 +293,7 @@ class CodeGenerator:
             # Create executed variable and generate code
             executed_variables[idx] = (
                 f"{self.clean_variable_name(class_type)}_"
-                f"{self.clean_variable_name(str(idx))}"
+                f"{self.sanitize_node_id(str(idx))}"
             )
             inputs = self.update_inputs(inputs, executed_variables)
 
@@ -315,7 +324,7 @@ class CodeGenerator:
             special_functions_code,
             code,
             workflow_data,
-            metadata_workflow_data or workflow_data,
+            metadata_workflow_data,
             queue_size,
             custom_nodes,
         )
@@ -386,7 +395,7 @@ class CodeGenerator:
         speical_functions_code: List[str],
         code: List[str],
         workflow_data: Dict,
-        metadata_workflow_data: Dict,
+        metadata_workflow_data: Dict | None,
         queue_size: int,
         custom_nodes=False,
     ) -> str:
@@ -397,13 +406,23 @@ class CodeGenerator:
             speical_functions_code (List[str]): A list of special functions code strings.
             code (List[str]): A list of code strings.
             workflow_data (Dict): The API workflow data used for runtime prompt execution.
-            metadata_workflow_data (Dict): The workflow metadata to embed into saved outputs.
+            metadata_workflow_data (Dict | None): The workflow metadata to embed into saved outputs.
             queue_size (int): Number of photos that will be generated by the script.
             custom_nodes (bool): Whether to include custom nodes in the code.
 
         Returns:
             str: Generated final code as a string.
         """
+        if metadata_workflow_data is None:
+            extra_pnginfo_code = "extra_pnginfo = None"
+        else:
+            extra_pnginfo_code = (
+                "extra_pnginfo = "
+                '{"workflow": json.loads('
+                + json.dumps(json.dumps(metadata_workflow_data))
+                + ")}"
+            )
+
         # Get the source code of the utils functions as a string
         func_strings = []
         for func in [
@@ -429,12 +448,7 @@ class CodeGenerator:
                 "\n\nadd_comfyui_directory_to_sys_path()\nadd_extra_model_paths()\n",
                 f"workflow = json.loads({json.dumps(json.dumps(workflow_data))})",
                 "prompt = json.loads(json.dumps(workflow))",
-                (
-                    "extra_pnginfo = "
-                    '{"workflow": json.loads('
-                    + json.dumps(json.dumps(metadata_workflow_data))
-                    + ")}"
-                ),
+                extra_pnginfo_code,
             ]
         )
         # Check if custom nodes should be included
@@ -628,12 +642,12 @@ class ComfyUItoPython:
         else:
             data = json.loads(self.workflow)
 
-        frontend_workflow_data = None
+        metadata_workflow_data = None
         if self.frontend_workflow:
             if isinstance(self.frontend_workflow, str):
-                frontend_workflow_data = json.loads(self.frontend_workflow)
+                metadata_workflow_data = json.loads(self.frontend_workflow)
             else:
-                frontend_workflow_data = self.frontend_workflow
+                metadata_workflow_data = self.frontend_workflow
 
         # Step 2: Initialize extra/custom nodes when requested or when the workflow references
         # a node class that is not currently loaded in the runtime.
@@ -657,7 +671,7 @@ class ComfyUItoPython:
         generated_code = code_generator.generate_workflow(
             load_order,
             data,
-            frontend_workflow_data,
+            metadata_workflow_data,
             queue_size=self.queue_size,
         )
 
diff --git a/tests/test_upscale_model_loader_export.py b/tests/test_upscale_model_loader_export.py
index 90827c9..27e3e22 100644
--- a/tests/test_upscale_model_loader_export.py
+++ b/tests/test_upscale_model_loader_export.py
@@ -57,6 +57,23 @@ class ImageUpscaleWithModel:
         return (image,)
 
 
+class MergeImages:
+    CATEGORY = "image"
+    FUNCTION = "merge"
+
+    @classmethod
+    def INPUT_TYPES(cls):
+        return {
+            "required": {
+                "left": ("IMAGE",),
+                "right": ("IMAGE",),
+            }
+        }
+
+    def merge(self, left, right):
+        return (left, right)
+
+
 class UpscaleModelLoaderExportTest(unittest.TestCase):
     def test_upscale_workflow_uses_direct_upscale_model_loader_init(self):
         workflow = {
@@ -102,7 +119,7 @@ class UpscaleModelLoaderExportTest(unittest.TestCase):
         self.assertIn("loadimage = LoadImage()", generated)
         self.assertIn("upscalemodelloader = UpscaleModelLoader()", generated)
         self.assertIn(
-            "imageupscalewithmodel__3 = imageupscalewithmodel.upscale(",
+            "imageupscalewithmodel_3 = imageupscalewithmodel.upscale(",
             generated,
         )
         self.assertNotIn('NODE_CLASS_MAPPINGS["UpscaleModelLoader"]()', generated)
@@ -169,6 +186,47 @@ class UpscaleModelLoaderExportTest(unittest.TestCase):
         self.assertIn("extra_pnginfo = None", generated)
         self.assertNotIn('"workflow": json.loads(', generated)
 
+    def test_export_preserves_unique_variable_names_for_subgraph_node_ids(self):
+        workflow = {
+            "1:23": {
+                "class_type": "LoadImage",
+                "inputs": {
+                    "image": "left.png",
+                },
+            },
+            "12:3": {
+                "class_type": "LoadImage",
+                "inputs": {
+                    "image": "right.png",
+                },
+            },
+            "20": {
+                "class_type": "MergeImages",
+                "inputs": {
+                    "left": ["1:23", 0],
+                    "right": ["12:3", 0],
+                },
+            },
+        }
+
+        output = StringIO()
+        ComfyUItoPython(
+            workflow=json.dumps(workflow),
+            output_file=output,
+            node_class_mappings={
+                "LoadImage": LoadImage,
+                "MergeImages": MergeImages,
+            },
+        )
+
+        generated = output.getvalue()
+
+        self.assertIn("loadimage_1_23 = loadimage.load_image(", generated)
+        self.assertIn("loadimage_12_3 = loadimage.load_image(", generated)
+        self.assertIn("mergeimages_20 = mergeimages.merge(", generated)
+        self.assertIn("left=get_value_at_index(loadimage_1_23, 0)", generated)
+        self.assertIn("right=get_value_at_index(loadimage_12_3, 0)", generated)
+
     def test_run_accepts_frontend_workflow_file_for_cli_metadata(self):
         workflow = {
             "1": {