The newly-released developer deeplinking feature provides Roblox developers with many new opportunities. However, this feature would be even more useful if it was properly supported in the in-game invite prompt. For example, allowing a user to send a join invite to a friend with a pre-filled lobby join code rather than having to copy-paste a link would largely improve the user experience for inviting friends to join a lobby.
I would suggest simply adding a launchData parameter to PromptGameInvite (e.g. SocialService:PromptGameInvite(player, launchData)) that is appended to the end of any link that is sent from that prompt.