diff --git a/wp-includes/rest-api.php b/wp-includes/rest-api.php
index 099fa9a64e..1c507e0524 100644
--- a/wp-includes/rest-api.php
+++ b/wp-includes/rest-api.php
@@ -1874,6 +1874,43 @@ function rest_find_one_matching_schema( $value, $args, $param, $stop_after_first
 	return $matching_schemas[0]['schema_object'];
 }
 
+/**
+ * Get all valid JSON schema properties.
+ *
+ * @since 5.6.0
+ *
+ * @return string[] All valid JSON schema properties.
+ */
+function rest_get_allowed_schema_keywords() {
+	return array(
+		'title',
+		'description',
+		'default',
+		'type',
+		'format',
+		'enum',
+		'items',
+		'properties',
+		'additionalProperties',
+		'patternProperties',
+		'minProperties',
+		'maxProperties',
+		'minimum',
+		'maximum',
+		'exclusiveMinimum',
+		'exclusiveMaximum',
+		'multipleOf',
+		'minLength',
+		'maxLength',
+		'pattern',
+		'minItems',
+		'maxItems',
+		'uniqueItems',
+		'anyOf',
+		'oneOf',
+	);
+}
+
 /**
  * Validate a value based on a schema.
  *
@@ -2765,30 +2802,8 @@ function rest_get_endpoint_args_for_schema( $schema, $method = WP_REST_Server::C
 
 	$schema_properties       = ! empty( $schema['properties'] ) ? $schema['properties'] : array();
 	$endpoint_args           = array();
-	$valid_schema_properties = array(
-		'type',
-		'format',
-		'enum',
-		'items',
-		'properties',
-		'additionalProperties',
-		'patternProperties',
-		'minProperties',
-		'maxProperties',
-		'minimum',
-		'maximum',
-		'exclusiveMinimum',
-		'exclusiveMaximum',
-		'multipleOf',
-		'minLength',
-		'maxLength',
-		'pattern',
-		'minItems',
-		'maxItems',
-		'uniqueItems',
-		'anyOf',
-		'oneOf',
-	);
+	$valid_schema_properties = rest_get_allowed_schema_keywords();
+	$valid_schema_properties = array_diff( $valid_schema_properties, array( 'default', 'required' ) );
 
 	foreach ( $schema_properties as $field_id => $params ) {
 
@@ -2802,10 +2817,6 @@ function rest_get_endpoint_args_for_schema( $schema, $method = WP_REST_Server::C
 			'sanitize_callback' => 'rest_sanitize_request_arg',
 		);
 
-		if ( isset( $params['description'] ) ) {
-			$endpoint_args[ $field_id ]['description'] = $params['description'];
-		}
-
 		if ( WP_REST_Server::CREATABLE === $method && isset( $params['default'] ) ) {
 			$endpoint_args[ $field_id ]['default'] = $params['default'];
 		}
diff --git a/wp-includes/rest-api/class-wp-rest-server.php b/wp-includes/rest-api/class-wp-rest-server.php
index 0844819568..3eeefda167 100644
--- a/wp-includes/rest-api/class-wp-rest-server.php
+++ b/wp-includes/rest-api/class-wp-rest-server.php
@@ -1380,6 +1380,8 @@ class WP_REST_Server {
 			}
 		}
 
+		$allowed_schema_keywords = array_flip( rest_get_allowed_schema_keywords() );
+
 		$route = preg_replace( '#\(\?P<(\w+?)>.*?\)#', '{$1}', $route );
 
 		foreach ( $callbacks as $callback ) {
@@ -1397,24 +1399,9 @@ class WP_REST_Server {
 				$endpoint_data['args'] = array();
 
 				foreach ( $callback['args'] as $key => $opts ) {
-					$arg_data = array(
-						'required' => ! empty( $opts['required'] ),
-					);
-					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'];
-					}
-					if ( isset( $opts['type'] ) ) {
-						$arg_data['type'] = $opts['type'];
-					}
-					if ( isset( $opts['items'] ) ) {
-						$arg_data['items'] = $opts['items'];
-					}
+					$arg_data             = array_intersect_key( $opts, $allowed_schema_keywords );
+					$arg_data['required'] = ! empty( $opts['required'] );
+
 					$endpoint_data['args'][ $key ] = $arg_data;
 				}
 			}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0d26f052ad..f93a25e5fb 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6-alpha-49256';
+$wp_version = '5.6-alpha-49257';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.