The Covenant of Redemption by its very name, is a covenant of grace.
There is a very limited sense in which that is true: We neither deserve nor necessitate God’s eternal purpose to redeem a people for himself. That said, the
covenant of redemption (
pactum salutis) is intratrinitarian, eternal, and economic; its parties are the Father, Son, and Spirit, and its logic is
covenantal obedience and reward within the mediatorial economy freely assumed by the Son. The Son receives a commission, a people, and a reward grounded in covenantal obedience, not grace.
By contrast, the
covenant of grace is vertical and federal. It is historical and postlapsarian, administered between God and fallen humanity through a mediator. Grace here is properly forensic and redemptive, presupposing sin, guilt, and the failure of the covenant of works (which was prelapsarian).
I would argue, then, that the covenant of redemption is the ontological and eternal foundation of the covenant of grace, not a subset of it. Grace is the historical fruit of the
pactum salutis, not a defining property of the pact itself.