diff --git a/.autograde/upload_metadata.py b/.autograde/upload_metadata.py
index 89dec80..8341ac5 100644
--- a/.autograde/upload_metadata.py
+++ b/.autograde/upload_metadata.py
@@ -98,8 +98,15 @@ def main() -> int:
     try:
         with urllib.request.urlopen(get_req) as resp:
             existing_file = json.loads(resp.read().decode())
-            sha = existing_file.get("sha")
-            print(f"File exists, updating (sha: {sha})")
+            # API may return a list (directory contents) or dict (single file)
+            if isinstance(existing_file, dict):
+                sha = existing_file.get("sha")
+                print(f"File exists, updating (sha: {sha})")
+            elif isinstance(existing_file, list):
+                # Response is a directory listing, file doesn't exist at this exact path
+                print(f"Path is a directory or file not found in expected format")
+            else:
+                print(f"Unexpected response type: {type(existing_file)}")
     except urllib.error.HTTPError as e:
         if e.code != 404:
             print(f"Error checking file existence: {e}", file=sys.stderr)