Use for any check. A rather brilliant effect that occupies the entirety of the class's most important asset slot.
First off, rules wise, keep in mind that you may not keep existing bonuses that might be in place for the tests you're replacing, if you use Mind's Eye to change an attack with an Knife for example, into a test you loose the +fight from the Knife because it's specifically a +.
Furthermore, since the test is changed when it's initiated, you cannnot commit cards of the original type to the test, thus you cannot commit a Deduction or Vicious Blow to Mind's Eye tests.
Mind's Eye unlocks a new role for characters to play. Usually a plays the "Flex", someone who can kill enemies and get clues, but often only after opening a certain window of power (I.E, buffing and playing the appropriate spell assets).
The new role is "Manager", the character who greases up gameplay for the team by digging out teammates, getting key evades, clues or just sniping a hard skill test required by a scenario card. Using Mind's Eye and some classic buffs a can punch an Acolyte and turn right around to pull up a clue from a 4+ shroud location and then parlay a tricky scenario card, all in the same turn and make it look easy!
One issue to Mind's Eye is that it's a way to beat tests, but it does'nt speed you up any, there is no damage bonus, no extra clues. You can however use it to swap around stats on some very weird tests, an investigation attempt with a Flashlight, executing an "I've got a plan!" or Waylay, obviously you can also play some tricks with guns and tools that grab clues or deal damage.
That said, it can still be slow going to use Mind's Eye for everything and charges are limited, so lean into that Manager role and use it not to get everything done yourself, use it to make sure everybody else is operating at top efficiency.
You can build some interesting and fresh variations of characters with this card, it really shines bright in off-class characters, especially Patrice Hathaway.