This paper presents Manas, a Semiotic Engineering epistemic tool for the design of collaborative systems (CoSys) whose aim is to expand the designers’ knowledge and awareness of their influence on groups and group dynamics. Manas has been developed to help designers represent their conception of computer-mediated communication and reflect upon some of its potential social effects, springing from user-system interaction, as well from user-user interaction (through the system). The paper illustrates how Manas can lead designers to reflect upon both the design problem and its proposed solution(s), which allows them to make more conscious decisions. Increased knowledge and awareness should then enhance the quality of CoSys design.