diff --git a/proto/site_pb2.py b/proto/site_pb2.py
new file mode 100644
index 0000000..363c2f6
--- /dev/null
+++ b/proto/site_pb2.py
@@ -0,0 +1,26 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""Protocol buffers for Monorail site-wide features."""
+
+from __future__ import print_function
+from __future__ import division
+from __future__ import absolute_import
+
+from protorpc import messages
+
+
+class UserTypeRestriction(messages.Enum):
+  """An enum for site-wide settings about who can take an action."""
+  # Anyone may do it.
+  ANYONE = 1
+
+  # Only domain admins may do it.
+  ADMIN_ONLY = 2
+
+  # No one may do it, the feature is basically disabled.
+  NO_ONE = 3
+
+  # TODO(jrobbins): implement same-domain users