diff --git a/metagpt/utils/text.py b/metagpt/utils/text.py
index dd9678438..921efe706 100644
--- a/metagpt/utils/text.py
+++ b/metagpt/utils/text.py
@@ -25,7 +25,7 @@ def reduce_message_length(
     """
     max_token = TOKEN_MAX.get(model_name, 2048) - count_string_tokens(system_text, model_name) - reserved
     for msg in msgs:
-        if count_string_tokens(msg, model_name) < max_token:
+        if count_string_tokens(msg, model_name) < max_token or model_name not in TOKEN_MAX:
             return msg
 
     raise RuntimeError("fail to reduce message length")