diff --git a/src/langbot/pkg/provider/modelmgr/token.py b/src/langbot/pkg/provider/modelmgr/token.py
index 9f477243..e1a71614 100644
--- a/src/langbot/pkg/provider/modelmgr/token.py
+++ b/src/langbot/pkg/provider/modelmgr/token.py
@@ -18,6 +18,8 @@ class TokenManager:
         self.using_token_index = 0
 
     def get_token(self) -> str:
+        if len(self.tokens) == 0:
+            return ''
         return self.tokens[self.using_token_index]
 
     def next_token(self):