diff --git a/jobrunner/create_or_update_jobs.py b/jobrunner/create_or_update_jobs.py
index 7597d0ea..b633d6dc 100644
--- a/jobrunner/create_or_update_jobs.py
+++ b/jobrunner/create_or_update_jobs.py
@@ -289,7 +289,7 @@ def assert_new_jobs_created(job_request, new_jobs, current_jobs):
     # is treated as a successful outcome because we've already done everything that was
     # requested.
     if RUN_ALL_COMMAND in job_request.requested_actions:
-        raise NothingToDoError()
+        raise NothingToDoError("All actions have already completed succesfully")
 
     # The other reason is that every requested action is already running or pending,
     # this is considered a user error.
@@ -298,7 +298,7 @@ def assert_new_jobs_created(job_request, new_jobs, current_jobs):
         current_job_states.get(action) for action in job_request.requested_actions
     }
     if requested_action_states <= {State.PENDING, State.RUNNING}:
-        raise JobRequestError("All requested actions were already scheduled to run")
+        raise NothingToDoError("All requested actions were already scheduled to run")
 
     # But if we get here then we've somehow failed to schedule new jobs despite the fact
     # that some of the actions we depend on have failed, which is a bug.
diff --git a/tests/test_create_or_update_jobs.py b/tests/test_create_or_update_jobs.py
index 23919f2c..b4df9c73 100644
--- a/tests/test_create_or_update_jobs.py
+++ b/tests/test_create_or_update_jobs.py
@@ -285,6 +285,15 @@ def make_job_request(action=None, actions=None, **kwargs):
     return job_request
 
 
+def test_create_jobs_already_requested(db, tmp_work_dir):
+    create_jobs_with_project_file(make_job_request(action="analyse_data"), TEST_PROJECT)
+
+    with pytest.raises(NothingToDoError):
+        create_jobs_with_project_file(
+            make_job_request(action="analyse_data"), TEST_PROJECT
+        )
+
+
 def create_jobs_with_project_file(job_request, project_file):
     with mock.patch("jobrunner.create_or_update_jobs.get_project_file") as f:
         f.return_value = project_file