diff --git a/main.py b/main.py
index ebbae13..9364a6a 100644
--- a/main.py
+++ b/main.py
@@ -77,7 +77,7 @@ class ChatCompletionRequest(BaseModel):
         example=[{"role": "user", "content": "你好，介绍一下你自己"}]
     )
     temperature: Optional[float] = Field(0.7, ge=0, le=2, description="随机性 (0-2)")
-    max_tokens: Optional[int] = Field(None, ge=1, description="最大生成 token 数")
+    max_tokens: Optional[int] = Field(None, description="最大生成 token 数（留空时使用模型默认值）", example=2048)
     stream: Optional[bool] = Field(False, description="是否使用流式输出")
     top_p: Optional[float] = Field(1.0, ge=0, le=1, description="核采样参数")
     n: Optional[int] = Field(1, ge=1, le=10, description="生成回复数量")