MAGNET is a testbed for exploring decision processes and agent interactions in the domain of multi-agent contracting. MAGNET agents negotiate contracts over multi-step plans that include temporal and precedence constraints, as well as price. Experimental research in this area requires a simulation environment that is sufficiently rich to be easily adapted to a variety of experimental purposes. The MAGNET testbed focuses on the process of determining the form and content of Requests for Quotations (RFQ’s), on the management of the bidding process, and on the evaluation of bids submitted by potential suppliers. All major decision processes are driven by plug-in components with documented API’s and a wealth of configuration parameters, and problem generation and data collection capabilities are well-suited to statistical studies.