right now you have to specify the exact name of the index for the hint to work. I'm finding a lot of cases where Mongo does not pick the right index when a sort is used. Using hint I need to specify the exact compound index and it make the code brittle because if the index is not there as-is then those queries will just fail. Hinting would be much more usable if it allows to match a prefix.
For example:

• index { tenantId, userId, time, coveredField }
• hint on { tenantId, userId }

  should just match that index