Left Panel: 1σ region of the jet boundary for a = −0.94, 0, and 0.94. We use the magnetization parameter σ = 1 condition as the jet-disk boundary and derive the 1σ variations and median of the polar angle θ for σ = 1 at a given radius r. The vertical lines are 1σ variations, and the dots are the median values. Right Panel: KDE of the polar angle θ such that σ = 1 at radius r = 10r _g . The nonspinning BH has the widest jet, corresponding to the largest θ, while the prograde disk with a = 0.94 has a wider jet than the retrograde disk with a = −0.94. In addition, the nonspinning BH has the narrowest peak, which suggests that the jet boundary of a nonspinning BH is the most stable.