diff --git a/endpoints/api/globalmessages.py b/endpoints/api/globalmessages.py
index b27683a17..d6b491d2f 100644
--- a/endpoints/api/globalmessages.py
+++ b/endpoints/api/globalmessages.py
@@ -58,6 +58,11 @@ class GlobalUserMessages(ApiResource):
         'message': {
           'type': 'object',
           'description': 'A single message',
+          'required': [
+            'content',
+            'media_type',
+            'severity',
+          ],
           'properties': {
             'content': {
               'type': 'string',
diff --git a/test/test_api_security.py b/test/test_api_security.py
index 0df692b17..40638dd24 100644
--- a/test/test_api_security.py
+++ b/test/test_api_security.py
@@ -4318,7 +4318,7 @@ class TestSuperUserMessages(ApiTestCase):
     def setUp(self):
       ApiTestCase.setUp(self)
       self._set_url(GlobalUserMessages)
-      self.message = {'message': {'content': '', 'severity': 'info', 'media_type': 'text/plain'}}
+      self.message = {'message': {'content': 'msg', 'severity': 'info', 'media_type': 'text/plain'}}
 
     def test_post_anonymous(self):
       self._run_test('POST', 401, None, None)