diff --git a/task-sdk/src/airflow/sdk/definitions/dag.py b/task-sdk/src/airflow/sdk/definitions/dag.py
index 479958b99d783..61268f16700a3 100644
--- a/task-sdk/src/airflow/sdk/definitions/dag.py
+++ b/task-sdk/src/airflow/sdk/definitions/dag.py
@@ -110,9 +110,7 @@
         "fileloc",
         "template_searchpath",
         "last_loaded",
-        "schedule",
-        # TODO: Task-SDK: we should be hashing on timetable now, not schedule!
-        # "timetable",
+        "timetable",
     }
 )
 
diff --git a/task-sdk/src/airflow/sdk/definitions/timetables/simple.py b/task-sdk/src/airflow/sdk/definitions/timetables/simple.py
index 3387cb3c386fd..7e00dcf9a0900 100644
--- a/task-sdk/src/airflow/sdk/definitions/timetables/simple.py
+++ b/task-sdk/src/airflow/sdk/definitions/timetables/simple.py
@@ -17,9 +17,12 @@
 
 from __future__ import annotations
 
+import attrs
+
 from airflow.sdk.bases.timetable import BaseTimetable
 
 
+@attrs.define
 class NullTimetable(BaseTimetable):
     """
     Timetable that never schedules anything.
@@ -30,6 +33,7 @@ class NullTimetable(BaseTimetable):
     can_be_scheduled = False
 
 
+@attrs.define
 class OnceTimetable(BaseTimetable):
     """
     Timetable that schedules the execution once as soon as possible.
@@ -38,6 +42,7 @@ class OnceTimetable(BaseTimetable):
     """
 
 
+@attrs.define
 class ContinuousTimetable(BaseTimetable):
     """
     Timetable that schedules continually, while still respecting start_date and end_date.