"The Culture" novels are Ian Banks, who does hard sci-fi. Just because it's super uber powerful, doesn't make it soft sci-fi. You can, with enough power, do almost anything. Throw in very, very advanced AI and some more power and there are few limits. But that's the point, there are limits. Things that still cannot be done, at all.
It's the lack of hand waving and magical components or elements (dilithium crystals for instance
) and the consistency that determine hard or soft sci-fi.
For your story, a throw away line about how projectiles don't work (or work really badly) on the shields and don't pursue it,
unless it's relavent to the plot/story. If projectiles work or not should only be mentioned if your main charcters (or minor
) meet an enemy who uses them.
I remember an Asimov book, one of the Laws of Robotics ones, which was awful for that. Plot and other points needed to be established, but it was done by characters telling each other what they already knew. Not all the time, but it wasn't good. However the ideas were new and interesting enough that it didn't matter.
In fact Dr A. is a good example, how the robots work just isn't discussed, unless the story needs it. Even then theres no (or little) extra detail, its distracting.