Smart character written by a smart writer: "Here's my simple plan with several alternative routes in case unforseen complications arise."
Smart character written by a stupid writer: "Here's my extremely elaborate plan with an absurd amount of moving parts, several of which are dependent on assumptions about how other people will act, and if any one thing doesn't go according to plan, then the whole thing falls apart, but that won't happen because I'm a super genius who can literally see the future, not because that's a superpower I have, but because the writers think smart people can predict anything, even with a near total lack of information."