diff --git a/endpoints/getting-started/openapi-appengine.yaml b/endpoints/getting-started/openapi-appengine.yaml
index 9aea095092..96fe0fc854 100644
--- a/endpoints/getting-started/openapi-appengine.yaml
+++ b/endpoints/getting-started/openapi-appengine.yaml
@@ -60,6 +60,7 @@ paths:
       - google_id_token: []
 definitions:
   echoMessage:
+    type: "object"
     properties:
       message:
         type: "string"