The Kind 2 Model Checker

Kind 2 is an open-source, multi-engine, SMT-based model checker for safety properties of finite-and infinite-state synchronous reactive systems. It takes as input models written in an extension of the Lustre language that allows the specification of assume-guarantee-style contracts for system components. Kind 2 was implemented from scratch based on techniques used by its predecessor, the PKind model checker. This paper discusses a number of improvements over PKind in terms of invariant generation. It also introduces two main features: contract-based compositional reasoning and certificate generation.