Add custom parameter to REST API request of a custom post type?

I solved following this answer and writing:

public function query_wasb_messages_by_status( $args, $request ) {

        if ( ! is_null( $request->get_param( 'message_status' ) ) ) {
            $args['meta_query'] = array(
                '_wasb_message_status' => array(
                    'key'     => '_wasb_message_status',
                    'value'   => (int) $request->get_param( 'message_status' ),
                    'compare' => '=',
                    'type'    => 'numeric'
                )
            );
        }

        return $args;

    }
add_filter( 'rest_wasb_message_query', array( $this, 'query_wasb_messages_by_status'), 10, 2 );

My problem is I used status as parameter name but status already exists for posts (‘draft’, ‘published’, etc…) so I changed the name to message_status…