diff --git a/src/runboat/k8s.py b/src/runboat/k8s.py
index ea35f6b..af946aa 100644
--- a/src/runboat/k8s.py
+++ b/src/runboat/k8s.py
@@ -262,6 +262,7 @@ async def delete_deployment_resources(build_name: str) -> None:
 @sync_to_async
 def kill_job(build_name: str, job_kind: DeploymentMode) -> None:
     # TODO delete all resources with runboat/build and runboat/job-kind label
+    assert job_kind in (DeploymentMode.initialize, DeploymentMode.cleanup)
     batchv1 = client.BatchV1Api()
     batchv1.delete_collection_namespaced_job(
         namespace=settings.build_namespace,