This paper describes a series of three design tools intended to support various forms of conflict management in concurrent and collaborative engineering settings. The tools are Explorer, ParMan (Parameter Manager), and PCA (Project Coordination Assistant). Explorer single-user parametric design assistant that allows many alternative designs satisfying multidisciplinary constraints to be generated and compared graphically. ParMan is a multi-user parametric design agent that permits distributed engineers to input constraints and evaluate the impact on the combined design space. PCA is a multi-user tool allowing engineers to encode and share semi-structured, non-parametric information about a project. Each of these tools is described below, along with experiences and motivation for development of the subsequent tool.