is @Column(type="json") valid?

The docs state no and there's only string|boolan|integer|decimal but the tests in the source show that there's a resource class with type="json" (Robot.php). I'm a little unsure what to expect when setting it - will it handle the json_encode / json_decode automatically?

Also, the dev tools converts json fields to string when creating models

Would also love to know the answer to this as I'm using the json type (though not via annotations) and always have to change thetype in the migration to Column::TYPE_JSON, which does exist so it's odd it doesn't seem to be able to generate the migration using it.