In this paper we present successively the proposition and the design of: 1) μ-tools adapted to collaborative activity of design, and 2) a multi-agent platform adapted to innovative and distributed design of products or services. This platform called PLACID (innovating and distributed design platform) must support applications of assistance to actors implies in a design process that we have called μ-tools. μ-tools are developed with an aim of bringing assistance to Co-design. The use of the paradigm agent as well relates to the modeling and the development of various layers of the platform, that those of the human-computer interfaces. With these objectives, constraints are added to facilitate the integration of new co-operative tools.