diff --git a/hub_core/routers/progress.py b/hub_core/routers/progress.py
index 63cf048..b1266b8 100644
--- a/hub_core/routers/progress.py
+++ b/hub_core/routers/progress.py
@@ -12,6 +12,9 @@ from hub_core.models.progress_event import ProgressEvent
 from hub_core.schemas.progress_event import ProgressEventCreate, ProgressEventRead
 from hub_core.utils.pagination import PageParams, apply_pagination
 
+# List/create progress events. ``workplan_id`` is the preferred filter/body field;
+# ``workstream_id`` remains a wire-compat alias until legacy-meter retires it.
+
 
 def create_progress_router(
     get_session: Callable[..., AsyncSession],