diff --git a/openedx/core/djangoapps/xblock/rest_api/urls.py b/openedx/core/djangoapps/xblock/rest_api/urls.py
index 2d88b1531f22..e44d6bd448ef 100644
--- a/openedx/core/djangoapps/xblock/rest_api/urls.py
+++ b/openedx/core/djangoapps/xblock/rest_api/urls.py
@@ -2,6 +2,7 @@
 URL configuration for the new XBlock API
 """
 from django.urls import include, path, re_path
+
 from . import views
 
 # Note that the exact same API URLs are used in Studio and the LMS, but the API
@@ -20,6 +21,7 @@
             # render one of this XBlock's views (e.g. student_view)
             re_path(r'^view/(?P<view_name>[\w\-]+)/$', views.render_block_view),
             # get the URL needed to call this XBlock's handlers
+            # NOTE: this endpoint is **unstable** and subject to changes in future
             re_path(r'^handler_url/(?P<handler_name>[\w\-]+)/$', views.get_handler_url),
             # call one of this block's handlers
             re_path(
diff --git a/openedx/core/djangoapps/xblock/rest_api/views.py b/openedx/core/djangoapps/xblock/rest_api/views.py
index c6fc9f42ec1f..299405adf858 100644
--- a/openedx/core/djangoapps/xblock/rest_api/views.py
+++ b/openedx/core/djangoapps/xblock/rest_api/views.py
@@ -139,6 +139,8 @@ def get_handler_url(request, usage_key_str, handler_name):
     the given XBlock handler.
 
     The URL will expire but is guaranteed to be valid for a minimum of 2 days.
+
+    Unstable - may change after Sumac
     """
     try:
         usage_key = UsageKey.from_string(usage_key_str)