What does “work off your tone” mean in this context from Modern Family?
Claire: (while walking on the street with her husband, Phil, she saw a guy on the other end and immediately frowns.) Oh, don’t look. There’s that jerk, Duane.
Phil: Oh, yuck.
Claire: i should say sth to him, shouldn’t I?
Phil: I gotta be honest. I was just **working off your tone**. Who’s Duane and why do we hate him?
Is “work off” here a phrasal verb or does this work specifically in this context only? What does the part marked in stars exactly mean? Thanks in advance!