i want to bound circle within a box

To respect the rectangle stroke width, you need to subtract it from the rectangle size,
As the size data is a 2D vector [x,y] and the stroke width is a single dimension float value you can put it twice in a 2D vector then subtract it from the size
var temp = << pickwip to insert it's code >> ;
var strokeWidth = [temp.temp] ;

then do the subtraction in parentheses before deviding by 2 (size - strokeWidth) /2

highlight this value [135,135] and use expression pickwip and choose the rectangle size then add /2

src=wiggle(2,200);
boundary = thisComp.layer("Shape Layer 1").content("Rectangle 1").content("Rectangle Path 1").size / 2; // size of boundinglayer/2
clamp(src, value - boundary, value + boundary)