The only case I can recall of Kraft getting involved in acquiring a player was the Moss trade, where he insisted on a face-to-face meeting before allowing the trade.Believe what you want. Doesn't change the fact that Kraft doesn't involve himself in signing FAs. It's part of the agreement that BB and he made that brought BB to the team. It's known that there the Krafts and BB have moral rules they follow when it comes to players, though they missed it on Hernandez.
Home grown players are a different story. Guys like Bruschi, Light, Wilfork, Brown, Edelman, Brady. Even then, though, Kraft has not gotten involved except on the extremely rare occasion.