diff --git a/environments/community/cat_behavior_env/cat_server.py b/environments/community/cat_behavior_env/cat_server.py
index fa94f0f6..3cdafc01 100644
--- a/environments/community/cat_behavior_env/cat_server.py
+++ b/environments/community/cat_behavior_env/cat_server.py
@@ -35,7 +35,7 @@ def load_cat_behaviors_for_prompt(filepath: str) -> str:
         return "\n".join(behaviors_description)
     except FileNotFoundError:
         return (
-            "\n\nWarning: Cat behaviors file not found at '{filepath}'. "
+            f"\n\nWarning: Cat behaviors file not found at '{filepath}'. "
             "You'll have to rely on your basic cat instincts (meow, hiss, purr, hairball, silence)."
         )
     except json.JSONDecodeError as e: