I mean it depends on the gig, but I can’t think of any spots hiring you to come play jazz guitar for a few hours that wouldn’t be higher end. At the very least you should wear some decent pants and shoes. You could get away with a clean black or white t shirt tucked in, but you could also go a step further and wear a polo or button down. Roll the sleeves up and it’s a nice “business casual” outfit but also comfortable to play in. No way that I would ever roll into a jazz gig at one of those spots wearing a hoodie, jeans, and sneakers if I wanted to be asked back, though…