diff --git a/ai_tool/models/ai_tool.py b/ai_tool/models/ai_tool.py
index c01eee29..82068020 100644
--- a/ai_tool/models/ai_tool.py
+++ b/ai_tool/models/ai_tool.py
@@ -48,7 +48,7 @@ def _get_tool_definition(self):
     @aitool(
         input_schema={},
         output_schema={
-            "date": {"type": "date"},
+            "date": {"type": "string", "format": "date"},
         },
     )
     def _ai_get_date(self):