The official TMO site has posted detailed about the "Spy" ability in the game.  Here is their explanation of this:

"I think I'd like a stealth ability where you can hide yourself in code, if you will.  Makes it harder for agents to track you and easier to sneak up on people." --LohanCross Subterfuge, misdirection, espionage...this is the focus of the Spy Ability Tree.   A character with Spy abilities can sneak past the guards, disable the security system, crack open the vault, disguise themselves as an office worker, and then walk out the front door.  Oh and if they need to, they can perform devastating sneak attacks. As if this wasn't enough, the Spy abilities also include "Tap Data Node."  Some of you might recall reading about this in my previous article on non-combat game play options.  Spies are the masters of Information gathering, and tapping Data Nodes is the single fastest way to acquire it. Lets take a look at some specific Spy abilities.  Disguise - Disguising one's self in the Matrix is far more than changing clothes, or putting on a fake moustache.  Characters with the Disguise Ability can make themselves physically appear as an NPC.  The actual disguise is determined by the specific disguise mask used.  (Note that the character in the new Spy themed wallpaper is wearing a disguise mask.)  Twistflip Escape - The character leaps backwards, as if doing a back flip.  At the same time, the player spins to the left.  Also known as a full gainer twist, this move can be used to evade just about anything.  Target is Stunned and Confused for 10 seconds while the character escapes from combat.  Freedom to Joints - In this sneak attack, the attacker comes up behind the opponent and places them in an arm bar.  Once the shoulder is snapped, the attacker proceeds to place the opponent into the chicken wing position, snapping the rest of the shoulder joint.  Finally, the attacker gets his opponent into the last hold, the shoulder lock, where he extends the arm outward, which not only destroys the rest of the shoulder joint, but also breaks the joints in the elbows.  The opponent falls to the ground with one arm in good condition, while the other flails lifelessly.