SING A BIT OF HARMONY

When the beautiful and mysterious Shion transfers to Keibu High School, she quickly becomes popular for her open-hearted personality and exceptional athletic talent… but she turns out to be an AI in the testing phase! Shion’s goal is to bring chronic loner Satomi "happiness". But her strategy is something no human would expect: she serenades Satomi in the middle of the classroom. After finding out that Shion is an AI, Satomi and her childhood friend, engineering geek Touma, steadily warm up to the new student. Along with the popular and attractive Gocchan, the strong-willed Aya, and judo club member "Thunder", they become more and more moved by Shion’s singing voice and earnestness even as her antics bewilder them. But what Shion does for Satomi’s sake ends up involving them all in some serious pandemonium… (Source: Funimation) — Description from AniList community (anilist.co).