diff --git a/src/memos/api/product_models.py b/src/memos/api/product_models.py
index 30df150e..f7f0304c 100644
--- a/src/memos/api/product_models.py
+++ b/src/memos/api/product_models.py
@@ -201,8 +201,8 @@ class APIADDRequest(BaseRequest):
     operation: list[PermissionDict] | None = Field(
         None, description="operation ids for multi cubes"
     )
-    async_mode: Literal["async", "sync"] = Field(
-        "async", description="Whether to add memory in async mode"
+    async_mode: Literal["async", "sync"] | None = Field(
+        None, description="Whether to add memory in async mode"
     )