diff --git a/src/banks/extensions/chat.py b/src/banks/extensions/chat.py
index 8747b77..fcc1c1f 100644
--- a/src/banks/extensions/chat.py
+++ b/src/banks/extensions/chat.py
@@ -49,7 +49,8 @@ def parse(self, parser):
             raise TemplateSyntaxError(error_msg, lineno)
 
         if attr_value.value not in SUPPORTED_TYPES:
-            msg = f"Unknown role type '{attr_value}', use one of ({",".join(SUPPORTED_TYPES)})"
+            types = ",".join(SUPPORTED_TYPES)
+            msg = f"Unknown role type '{attr_value}', use one of ({types})"
             raise TemplateSyntaxError(msg, lineno)
 
         # Pass the role name to the CallBlock node