The paper describes the design research process of a procedural content generation tool aimed at supporting creative game design processes. An author oriented approach to procedural content generation tools is used where these tools can be manipulated so as to let authors define the design space they want to explore and the design solution they wish to find, therefore maintaining their creative agenda intact. We present two Participatory Design exercises where game designers were tasked with creating a complete Interface Design for an implementation of this approach. Content Analysis from participants’ discourse during these design exercises showed two important results. First, designers have trouble understanding how this procedural content generation works, and how to express their design problem within its conceptual framework. Second, subjects were averse to a pure optimization led approach to content generation and suggested the need for an exploratory phase, where content is created only to grasp the design landscape, without having to specifically define the desired solution.