One idea is a 'deceive' command, or something similar. Basically, every time your character is hiding something from another character (in person) you type this command to roll Charisma vs Perception (specifically Personality vs Awareness.) If you win, they never know you rolled it. If they win, however, they get a message like, . o O ( Something is off here... )
This would not just be for outright lying. This would extend to half-truths, poker faces, hiding emotion, etcetera.
Obviously, certain chrome would guarantee success.