"He is a trained psychologist. He knows all the trigger points of mental drills, mental skills, rituals, mental toughness drills," said Ireland Team Manager Mick Kearney.
"It is about looking at the marginal gains. The margins are so tight at international level that the winning and losing of a game can depend on the tiniest little things.
"If Enda can actually bring a ƒ% or 1% extra to the players and to the team and to the environment that could be the difference between actually winning and losing.
"The secret really to what Enda does is the way he communicates. People can have all the training in the world. But, if they can't communicate well in a team environment it doesn't actually work.
"My experience of working with Enda and his success with Leinster and other individuals that he has worked with would lead you to believe he will do an excellent job with us."
McNulty is no stranger to working with rugby players.
He has had previous experience with the Ireland U20s and Leinster Rugby and has been used by Brian O'Driscoll on an ongoing basis, partly as a sports psychologist and partly as a life skills coach.
Indeed, O'Driscoll recently recommended him as a source of comfort when experiencing a drop-off in form in 2008 when McNulty got him to refocus on what he could do right rather than what he was doing wrong.
"I have never worked with Enda before. But, I am very much looking forward to it. I think it is a great resource for us to have," responded Ulster flanker Chris Henry.
"For myself personally, there is a guy Hugh Campbell (currently working with Kildare footballers) in Belfast who has worked with a number of the Ulster players. I have known him since I have been in the (Ulster) Academy.
"It is not something I would go and do weekly. It is basically when I feel I need to have a talk or advice about form or man management stuff."
McNulty will be a busy man in his time with Ireland. Seven players, namely Leinster's Kevin McLaughlin and Rhys Ruddock, Munster's James Coughlan, Tommy O'Donnell, Ian Keatley, Damien Varley and Mike Sherry, have been added to an already extended squad, bringing the total to 46 players.