Developing human-centered agent architectures requires the integral consideration of architectural flexibility, teamwork adaptability, and context reasoning capability. With the integration of various forms of team intelligence including shared teamwork process and progress, dynamic context management and information dependency reasoning, and recognition-primed collaborative decision mechanism, R-CAST offers a flexible solution to developing cognitive aids for the support of human-centered teamwork in information and knowledge intensive domains. In this paper, we present the key features of R-CAST. As evidence of its applications in complex real-world problems, we give two experimental evaluations of R-CAST as teammates and decision aids of human Command and Control teams.