@toothlessdragon Coconut + MyPy integration is heavily in development right now. Currently, we are waiting on the fix in python/mypy#1839 to get released in a new MyPy version, since that fix is necessary for MyPy to be able to properly parse compiled Coconut. Once that fix is out, you will be able to run MyPy on your compiled Coconut just fine. Additionally, once that's working, the plan is for Coconut to support a nicer-looking type definition syntax than the MyPy default that will compile down to basic MyPy. If you have an idea of what you'd like that syntax to look like, leave a comment on #121, the issue that's tracking that change.