A surgical tool comprising: a tubular instrument shaft extending along a longitudinal axis and having a proximal end, a distal end, and a bore between the proximal end and the distal end; the longitudinal axis extending through the proximal and distal ends;a two-degree of freedom wrist comprising an intermediate member pivotally coupled with the tubular instrument shaft to rotate relative to the tubular instrument shaft about a first axis that is transverse to the longitudinal axis, the intermediate member having an exterior width along the first axis and an exterior length along a second axis that is transverse to the first axis and transverse to the longitudinal axis, the second axis being offset from the first axis along the longitudinal axis; an end effector pivotally coupled with the intermediate member to rotate relative to the intermediate member about the second axis, the end effector including four attachment features, each of the four attachment features including a curved portion, each of the four curved portions having a center-of-curvature and a curved ordinary centerline passing through cross-sectional center of the respective curved portion, each of the four center-of-curvatures being located in a plane containing the second axis, and each of the four curved ordinary centerlines being tangent to a plane containing the first axis; and four tension members extending along the tubular instrument shaft so that opposed axial movement of the tension members angularly orients the end effector relative to the tubular instrument shaft about the first and second axes, each of the four tension members being interfaced with a respective one of the four curved portions and configured to slide along the respective curved portion and rotate around the respective curved portion during pivoting of the end effector about the first and second axes. a tubular instrument shaft extending along a longitudinal axis and having a proximal end, a distal end, and a bore between the proximal end and the distal end; the longitudinal axis extending through the proximal and distal ends;a two-degree of freedom wrist comprising an intermediate member pivotally coupled with the tubular instrument shaft to rotate relative to the tubular instrument shaft about a first axis that is transverse to the longitudinal axis, the intermediate member having an exterior width along the first axis and an exterior length along a second axis that is transverse to the first axis and transverse to the longitudinal axis, the second axis being offset from the first axis along the longitudinal axis; an end effector pivotally coupled with the intermediate member to rotate relative to the intermediate member about the second axis, the end effector including four attachment features, each of the four attachment features including a curved portion, each of the four curved portions having a center-of-curvature and a curved ordinary centerline passing through cross-sectional center of the respective curved portion, each of the four center-of-curvatures being located in a plane containing the second axis, and each of the four curved ordinary centerlines being tangent to a plane containing the first axis; and four tension members extending along the tubular instrument shaft so that opposed axial movement of the tension members angularly orients the end effector relative to the tubular instrument shaft about the first and second axes, each of the four tension members being interfaced with a respective one of the four curved portions and configured to slide along the respective curved portion and rotate around the respective curved portion during pivoting of the end effector about the first and second axes.