I'm looking for the opposite of "error-prone", specifically in the context of programming style. As in, "Jack has not-error-prone coding style".
Some words that are inappropriate for this context are "infallible", "error-less" and "unfailing". Nobody writes infallible code. "Reliable" hits a little closer to home, but it describes the outcome more than the process. If you have error-prone coding style, it just takes longer to get your program to function reliably.