The paper presents a knowledge representation formalism for multi-agent systems, where different autonomous agents reason and act in a shared environment. Agents are autonomously pursuing individual goals, but are capable of interacting through a shared knowledge repository and collaborative actions. In their interaction through shared portions of the world, agents deal with problems of synchronization and concurrency, and have to realize coordination by developing proper strategies and policies in order to ensure a consistent global execution of their autonomously derived plans. To model this kind of knowledge, the paper proposes an high-level Action Description Language (ADL). A distributed planning problem is formalized by providing a number of declarative specifications of the portion of the problem pertaining a single agent. Each of these specifications is executable by a stand-alone CLP-based planner. The coordination among agents exploits a Linda-like infrastructure. This is a working project and a concrete implementation of the system is being developed in SICStus Prolog.