Technical conditions and actor behavior both affect the evolution of Industrial Symbiosis Networks (ISNs) that exchange local materials and energy in a Circular Economy. In order to design interventions that shape ISNs toward financially robust exchanges, it is necessary to understand the effects of different actor behaviors during waste exchange negotiations. This study aimed to show to what extent and how the financial robustness of ISNs is influenced by negotiation behavior of ISN firms. We created an agent-based model based on empirical data and literature, in which the Theory of Planned Behavior (TPB) can be added to a tit-for-tat negotiation process. The model showed that the added self-evaluation and feedback to behavioral intention and behavior of actors is crucial for the sta-bility of ISNs. In addition, model simulations revealed divergent financial results for waste suppliers when we compare different design scenarios, indicating that the model contributes to understanding effects of design interventions in ISNs. In the future, we will calibrate the model with more empirical evidence, and ex-tend the experiments with other scenarios.