At the core of design practices is action, to ‘make-do’. As a contribution to the discussion on post-anthropocentric design, this short essay draws on assemblage theory to question how to ‘make-do’. Methodologically, the inquiry opens six cases of service and system design contexts where agential capacities emerge from non-linear system interactions, skilling platforms, tactical resistances, mattering materialities, struggles in organisation cultures or even non-action. Assemblage theory proves resourceful to delineate how these agencies form and develop. Inconclusion, this essay proposes research avenues brought by assemblage theory to design practices about the distinction of designers and users, the building of strategies and the creation of value.