diff --git a/metagpt/memory/brain_memory.py b/metagpt/memory/brain_memory.py
index 384c4d3a9..56b13c875 100644
--- a/metagpt/memory/brain_memory.py
+++ b/metagpt/memory/brain_memory.py
@@ -302,7 +302,7 @@ class BrainMemory(BaseModel):
             return text
         system_msgs = [
             "You are a tool for summarizing and abstracting text.",
-            "Return the summarized text to less than 200 words.",
+            f"Return the summarized text to less than {max_words} words.",
         ]
         if keep_language:
             system_msgs.append("The generated summary should be in the same language as the original text.")