You can set CommandMeta.DESCRIPTION to a string and use that as a translation key with MinecraftHelp's description decorator, but that description is also used as the BukkitCommand's description making it show up on the bukkit help page as shown below.

I think the 4 separate CommandMeta keys for descriptions warrant a rethink of how v2 will handle descriptions while at all points providing a way to determine what a description is based on the command sender type (for translations).