Agent-based supply chain models are build using small entities (agents), which might represent a single company.
Each of the agents has its own goals and rules of operation programmed into a computer. The interaction between several agents of this kind leads to a more realistic and complex behavior of the system.
This is a review of another chapter of the book by Zsidisin and Ritchie (Supply Chain Risk). The book can be bought at amazon.com, if you are interested in reading more.