Register Rest Route with args

Hi everyone,

I am creating my own rest route and want to pass some variables to the permission callback function. This is the register_rest_route that I have to date:

        register_rest_route('1.00', '/trial/confirm', array(
            'methods' => 'POST',
            'callback' => array($trial_service, 'callback_confirm'),
            'permission_callback' => array($this, 'check_permission_master'),
            'args' => array(
                'token' => array(
                    'required' => true,
                    'sanitize_callback' => 'esc_attr'
                )
            )
        ));

How can I pass variables to check_permission_master ? Any help much appreciated. Thanks.