Through a case study on the interaction between artificial intelligence(Ai) and Irish traditional music, we investigate contested issues of artistic agencyand the meaning of the “authentic” in a world of Ai-generated music. Weconsider musical authenticity from three perspectives: 1) the source/cause of art;2) the art itself; and 3) the recipient. Throughout, we adopt a posthumanistframework that ascribes agency to both human and non-human actors. Weinterpret authenticity as a relative, malleable concept and argue that thepartnership between Ai and folk music enriches each of these perspectives. Thispaper adds to the intensifying debate around the application, evaluation, ethics,and future of Ai-generated music.