A system and method for modeling a message-passing program module using type annotations is disclosed. The message-passing program module is constructed with operations that communicate with operations of other message-passing program modules in an asynchronous computing environment. Type annotations are communication protocols that represent processes of input and/or output actions that the program module developer expects each operation to perform or take on a selected set of communication channels. During development of the program module, the type annotations are declared at each operation of the program module. Soundness of the type annotations and whether implementation of the program module conforms to the type annotations is checked using a type system. If the program module is well-typed and well-implemented, the type system abstracts a behavioral module of the message-passing program module that reflects the relevant processes expressed by the type annotations. A model checker determines whether the behavioral module is in fact a valid abstraction of the implementation, and if so, evaluates one or more properties of the behavioral module to render a conclusion about these properties for the program module.