His costume is actually part of his disguise. By the time I was doing some combat in the Marvel One Shots - wearing my black Dolce & Gabbana suit, which is actually really flexible and breathable - my costume really started to feel like my uniform. It’s not the same as the Mark V Iron Man suit or Hawkeye’s amazing S.H.I.E.L.D. gear, but it really is Coulson’s uniform. And when I put on that suit and shirt and tie, and sometime my sunglasses, I kind of do feel like I’m back home again. When I put on my costume and walked onto the set of the The Avengers, and walked into a room on the Helicarrier with everybody else in their uniforms, I felt like one of the super heroes who is part of the Avengers - and my uniform just happens to be very expensive black material.