This is a design responsibility as outlined in the newly revised ACI 315 standard. The contractor is now required to exactly follow the original design. Articulate construction joints with rustication strips. Gasket, silicone caulk, or otherwise seal all construction, corners and form butt joints. It is best to place rustication strips over form joints to avoid variations in results opposite the joint.
Architectural concrete is as different from rough concrete as millwork is from rough carpentry.
Details and specifications must be clear. Review your concrete form specifications to be sure they produce the results you want for your client.