Social viscosity is the resistance exerted to one another’s action flow between networked social actors, either human or nonhuman. This chapter explores how the design of nonhuman agents intended to mediate people’s interactions could partially determine the social viscosity of a social practice, thus facilitating or hindering the achievement of cooperative or collaborative interactions. The triadic unit of analysis described herein regards nonhumans as constituent participants of activities, rather than mere tools or equipment; moreover, it enables researchers to dissect the assembled meanings and mediated intentionalities occurring in micro-social interactions between social actors. The comparative study of navigation flows of pedestrians walking toward each other on regular crosswalks and on a smart crosswalk prototype illustrates how a computational nonhuman scripted to preserve the social balance might adaptively display suggestions for alternative paths aiming to avoid forecasted interruptions of walking flows. The research offers recommendations and insights for the design of socially apt smart artifacts aimed to prompt cooperative social interactions, enhance the actor-network’s information integrity, and stage the focus of activity.