As far as failure mode -- missing suggestions is rather unavoidable, isn't it? So occasional wrong suggestions would be fun as long as they're clearly shown. Something like "I'm not sure, but there might be a solution with..." would be ideal; it lets me explore knowing that it might be a wrong direction.
Re pricing: one-time purchase or BYO model makes a lot of sense for this kind of personal workflow tool.
More context on the direction I’m validating is in my HN profile/bio if you want to compare notes.