diff --git a/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py b/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
index a447dad0b1..b2eda5a8d3 100644
--- a/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
+++ b/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
@@ -971,18 +971,23 @@ def _update_metadata_with_tags_in_header(request: Request, metadata: dict) -> di
     Used for google and vertex JS SDKs, and Azure passthrough
     Checks both 'tags' and 'x-litellm-tags' headers
     """
-    # Initialize tags list if it doesn't exist
-    if "tags" not in metadata:
-        metadata["tags"] = []
-    
+    tags_to_add = []
+
     # Check for 'tags' header first
     _tags = request.headers.get("tags")
     if _tags:
-            metadata["tags"].extend([tag.strip() for tag in _tags.split(",")])
+        tags_to_add.extend([tag.strip() for tag in _tags.split(",")])
 
     _tags = request.headers.get("x-litellm-tags")
     if _tags:
-            metadata["tags"].extend([tag.strip() for tag in _tags.split(",")])
+        tags_to_add.extend([tag.strip() for tag in _tags.split(",")])
+
+    # Only add tags key if there are tags to add
+    if tags_to_add:
+        if "tags" not in metadata:
+            metadata["tags"] = []
+        metadata["tags"].extend(tags_to_add)
+
     return metadata