Nostr devs: is the Tags array the right place to add app-specific metadata related to an event?

If so, is there a tag type for this? In the nips I see type “e”, “p”, “r”, and “g”. Is it reasonable to just use a new one?

If not, where should we encode application-specific metadata? Is it preferred to use a custom kind and e.g. json encode data in the content field?