diff --git a/kb_workflow/cli.py b/kb_workflow/cli.py
index ca2fe0f..ffed9dd 100644
--- a/kb_workflow/cli.py
+++ b/kb_workflow/cli.py
@@ -165,7 +165,7 @@ def login_command(
         result = login.login_by_qrcode()
         if result.success and result.cookie_str:
             manager.save_cookie(result.cookie_str)
-        return result.model_dump()
+        return result.model_dump(mode='json')
 
     except Exception as e:
         return {"success": False, "error": str(e)}