Fragile Minds is a great addition to Spycraft. If I had to mark it down in some way, my issue would be that this mostly stuff that should've been in the main book; it's that cool.
Fragile Minds adds rules on madness to Spycraft. There's the Table Of Sproing (psychological complement to the Table Of Ouch in Spycraft), plots involving madness,campaign qualities and even creatures with an unnatural, maddening look to them.
Even if you don't plan on your spies meeting Arcane Horrors From Beyond, the usefulness for a campaign with surreal or psychological overtones is hard to overstate.
[5 of 5 Stars!]