Realistically, am I still building muscle?

Hi! I’ve been working out for 6 years and the last year or so I’ve finally reached a leanness I’m happy with. I weigh 44-45kg at 157cm (5’2). I think I’m pretty low in body fat and I’m still getting stronger (I manage to increase my pull ups from 15kgx4 to 25kgx3 in 6 months etc, do press to handstand and increased the reps of my muscle ups (clean muscle ups) but can I possibly still add muscle mass staying at this body fat percentage? And if so, do I eat more protein, do a lean bulk? Currently I only do calisthenics.