You can use the XBL variable to create commands that display information about a specific Xbox Live profile.
gamertag is the Xbox Live gamertag being looked up
would result in
night has a gamerscore of 105056 and is currently online playing Call of Duty®: Black Ops III Playing Multiplayer on Call of Duty®: Black Ops III.
Adding a command to show chatters your gamertag stats
!commands add !xbl $(xbl
Adding a command to allow users in chat to lookup their own gamertag
!commands add !xbllookup $(xbl $(query))