Index: src/wp-includes/rest-api/class-wp-rest-server.php
===================================================================
--- src/wp-includes/rest-api/class-wp-rest-server.php	(revision 35483)
+++ src/wp-includes/rest-api/class-wp-rest-server.php	(working copy)
@@ -1064,6 +1064,12 @@
 					if ( isset( $opts['default'] ) ) {
 						$arg_data['default'] = $opts['default'];
 					}
+					if ( isset( $opts['enum'] ) ) {
+						$arg_data['enum'] = $opts['enum'];
+					}
+					if ( isset( $opts['description'] ) ) {
+						$arg_data['description'] = $opts['description'];
+					}
 					$endpoint_data['args'][ $key ] = $arg_data;
 				}
 			}