When testing a library, developers typically first have to capture the semantics they want to check. They then write the code implementing these tests and find relevant test cases that expose possible misbehaviours. In this work, we present a tool that automatically takes care of these last two steps by automatically generating fuzz testing suites from OCaml interfaces annotated with formal behavioural specifications. We also show some ongoing experiments on the capabilities and limitations of fuzzing applied to real-world libraries.