diff --git a/rest-api-spec/api/indices.put_mapping.json b/rest-api-spec/api/indices.put_mapping.json
index 33390b90a12..3a246f60155 100644
--- a/rest-api-spec/api/indices.put_mapping.json
+++ b/rest-api-spec/api/indices.put_mapping.json
@@ -28,6 +28,8 @@
         }
       }
     },
-    "body": null
+    "body": {
+      "description" : "The mapping definition"
+    }
   }
 }