diff --git a/utilities/aws_lambda/subtask_handler.py b/utilities/aws_lambda/subtask_handler.py
index 592ffebf..42c9e07a 100644
--- a/utilities/aws_lambda/subtask_handler.py
+++ b/utilities/aws_lambda/subtask_handler.py
@@ -4,6 +4,7 @@ Translates an AWS Lambda invocation (SQS-shaped or direct) into
 TaskOrchestrator.run_subtask(...) calls.
 """
 
+import inspect
 import json
 import logging
 import os
@@ -37,6 +38,8 @@ def subtask_handler(
     factory = orchestrator_cm or default_orchestrator
 
     def decorator(func: Callable[..., Any]) -> Callable[..., Any]:
+        _wants_orchestrator = len(inspect.signature(func).parameters) >= 3
+
         @wraps(func)
         def wrapper(event: dict[str, Any], context: Any) -> None:
             cloud_logs_url = _cloudwatch_url()
@@ -45,12 +48,22 @@ def subtask_handler(
                     body = _parse_body(record)
                     trigger = SubtaskTriggerBody.model_validate(body)
                     logger.info("Running subtask %s", trigger.sub_task_id)
+                    def _work_with(
+                        _body: dict[str, Any] = body,
+                        _o: TaskOrchestrator = orchestrator,
+                    ) -> Any:
+                        return func(_body, context, _o)
+
+                    def _work_without(_body: dict[str, Any] = body) -> Any:
+                        return func(_body, context)
+
+                    work: Callable[[], Any] = (
+                        _work_with if _wants_orchestrator else _work_without
+                    )
                     try:
                         orchestrator.run_subtask(
                             trigger.sub_task_id,
-                            work=lambda body=body, o=orchestrator: func(
-                                body, context, o
-                            ),
+                            work=work,
                             cloud_logs_url=cloud_logs_url,
                         )
                     except Exception: