Custom Properties value in Animation Nodes I'd like to directly control custom properties of my empties and bones in Animation Nodes tree, to avoid location, scale and rotation manipulation. "Object Attribute Input" doesn't work, even after using copy data path.

My workaround is to create empty with scale controlled by custom properties, and this scale attribute is used in Animation Nodes tree, but I hope, I can do it .
You can use expression node to control property of object. Use ctrl+shift+alt+c on a property to get code. use that code inside expression node to get or set the data.

For example an object Empty has two custom properties A and B. We can get value of A
using bpy.data.objects["Empty"]["A"]. Similarly we can set value to B using bpy.data.objects["Empty"]["B"]=x where x is the data we provide.



Or you can replace the object name and property name by,