diff --git a/rwx/fs/__init__.py b/rwx/fs/__init__.py
index c91e0b8..9189778 100644
--- a/rwx/fs/__init__.py
+++ b/rwx/fs/__init__.py
@@ -23,7 +23,7 @@ def empty_file(path: str) -> None:
 
 
 def get_mount_uuid(path: str) -> str:
-    """Return the UUID of provided mountpoint path."""
+    """Return the filesystem UUID of a mountpoint path."""
     return ps.run_line(
         ("findmnt",),
         ("--noheadings",),
@@ -32,7 +32,8 @@ def get_mount_uuid(path: str) -> str:
     )
 
 
-def get_path_mount(path: str):
+def get_path_mount(path: str) -> str:
+    """Return the mountpoint path of an arbitrary path."""
     return ps.run_line(
         ("stat",),
         ("--format", "%m"),
@@ -40,11 +41,13 @@ def get_path_mount(path: str):
     )
 
 
-def get_path_uuid(path: str):
+def get_path_uuid(path: str) -> str:
+    """Return the filesystem UUID of an arbitrary path."""
     return get_mount_uuid(get_path_mount(path))
 
 
-def make_directory(path: str):
+def make_directory(path: str) -> None:
+    """Make a directory (and its parents) from a path."""
     os.makedirs(path, exist_ok=True)