What skill would be appropriate to playing a musical instrument? In Far horizons, there are some instruments in the gear section, but no mechanics for using them (that I saw).
I'm thinking it might be Charm . You're on stage, you want to impress the audience. Make a Charm check. An instrument can have the "right tools for the job" effect and add a Boost die.
Other social skills might work too. Play your instrument and make a Leadership check to bolster your allies during or before combat; a battle bard. Playing several notes of a popular dirge might be useful in a Coercion check.
And maybe that's simply what instruments are: the right tools for the job for social skills. No instrument playing skill required.
Or perhaps this is an instance where a custom skill could be created. Music (Presence). Make it a non-career skill for everyone. Maybe for the Performer spec, replace Melee with Music as a career skill.
Thoughts?