Despite their benefits, programmers rarely use formal specifications, because they are difficult to write and they require an up front investment in time. To address these issues, we present a tool that helps programmers write and debug algebraic specifications. Given an algebraic specification, our tool instantiates a prototype that can be used just like any regular Java class. The tool can also modify an existing application to use the prototype generated by the interpreter instead of a hand-coded implementation. The tool improves the usability of algebraic specifications in the following ways: (i) A programmer can "run" an algebraic specification to study its behavior. The tool reports in which way a specification is incomplete for a client application. (ii) The tool can check whether a specification and a hand-coded implementation behave the same for a particular run of a client application. (iii) A prototype can be used when a hand-coded implementation is not yet availa...