diff --git a/libcst/tool.py b/libcst/tool.py
index ee4f36738..cb72b75f6 100644
--- a/libcst/tool.py
+++ b/libcst/tool.py
@@ -607,11 +607,16 @@ def _list_impl(proc_name: str, command_args: List[str]) -> int:  # noqa: C901
                 file=sys.stderr,
             )
             continue
+        path = imported_module.__file__
+        if path is None:
+            print(
+                f"Module {module} doesn't have a path, cannot list codemods inside it",
+                file=sys.stderr,
+            )
+            continue
 
         # Grab the path, try to import all of the files inside of it.
-        # pyre-fixme[6]: For 1st argument expected `PathLike[Variable[AnyStr <:
-        #  [str, bytes]]]` but got `Optional[str]`.
-        path = os.path.dirname(os.path.abspath(imported_module.__file__))
+        path = os.path.dirname(os.path.abspath(path))
         for name, imported_module in _recursive_find(path, module):
             for objname in dir(imported_module):
                 try:
@@ -683,7 +688,7 @@ def _invalid_command(proc_name: str, command_args: List[str]) -> int:
         "initialize": _initialize_impl,
         "list": _list_impl,
     }
-    return lookup.get(args.action or None, _invalid_command)(proc_name, command_args)
+    return lookup.get(args.action or "", _invalid_command)(proc_name, command_args)
 
 
 if __name__ == "__main__":
diff --git a/pyproject.toml b/pyproject.toml
index 6bd6bad17..1ccd6d1bb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -106,3 +106,11 @@ before-all = "rustup target add aarch64-apple-darwin x86_64-apple-darwin"
 
 [tool.cibuildwheel.windows]
 before-all = "rustup target add x86_64-pc-windows-msvc i686-pc-windows-msvc"
+[tool.pyrefly]
+search_path = ["stubs", "."]
+project_includes = ["**/*"]
+project_excludes = [
+    "**/.[!/.]*",
+    "native/**",
+    "setup.py",
+]