diff --git a/rwx/cmd/squashfs/__init__.py b/rwx/cmd/squashfs/__init__.py
index 322186c..85e20b2 100644
--- a/rwx/cmd/squashfs/__init__.py
+++ b/rwx/cmd/squashfs/__init__.py
@@ -1,3 +1,5 @@
+"""Wrap SquashFS commands."""
+
 import ps
 
 import rwx.cmd
@@ -5,7 +7,8 @@ import rwx.cmd
 rwx.cmd.need("mksquashfs")
 
 
-def mksquashfs(input_root: str, output_file: str):
+def mksquashfs(input_root: str, output_file: str) -> None:
+    """Make a SquashFS bootable image file."""
     ps.run(
         [
             "mksquashfs",
diff --git a/rwx/deb/__init__.py b/rwx/deb/__init__.py
index e9c6a9e..f022ca5 100644
--- a/rwx/deb/__init__.py
+++ b/rwx/deb/__init__.py
@@ -1,3 +1,5 @@
+"""Wrap Debian commands."""
+
 import cmd
 
 import ps
@@ -8,7 +10,8 @@ BOOTSTRAP_ARCHITECTURE = "amd64"
 BOOTSTRAP_VARIANT = "minbase"
 
 
-def bootstrap(root_path: str, suite: str, mirror_location: str):
+def bootstrap(root_path: str, suite: str, mirror_location: str) -> None:
+    """Boostrap a base operating filesystem."""
     command = [
         ("debootstrap",),
         ("--arch", BOOTSTRAP_ARCHITECTURE),
diff --git a/rwx/err/__init__.py b/rwx/err/__init__.py
index b996913..294d8d8 100644
--- a/rwx/err/__init__.py
+++ b/rwx/err/__init__.py
@@ -1,2 +1,5 @@
-class Exception(Exception):
-    pass
+"""Handle errors."""
+
+
+class Error(Exception):
+    """Parent class for all errors."""
diff --git a/rwx/fs/__init__.py b/rwx/fs/__init__.py
index c91e0b8..514fcec 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)
 
 
@@ -53,15 +56,16 @@ def read_file(file_path: str):
         return file_object.read()
 
 
-def read_file_lines(file_path: str, charset=CHARSET):
+def read_file_lines(file_path: str, charset: str = CHARSET):
     return read_file_text(file_path).split(os.linesep)
 
 
-def read_file_text(file_path: str, charset=CHARSET):
+def read_file_text(file_path: str, charset: str = CHARSET):
     return read_file(file_path).decode(charset)
 
 
-def wipe(path: str):
+def wipe(path: str) -> None:
+    """Wipe provided path, whether directory or file."""
     try:
         shutil.rmtree(path)
     except NotADirectoryError:
@@ -70,6 +74,7 @@ def wipe(path: str):
         pass
 
 
-def write(file_path: str, text: str, charset=CHARSET):
+def write(file_path: str, text: str, charset: str = CHARSET) -> None:
+    """Write text into a file."""
     with open(file_path, "bw") as file_object:
         file_object.write(text.encode(charset))
diff --git a/rwx/grub/__init__.py b/rwx/grub/__init__.py
index cd016ab..dde847a 100644
--- a/rwx/grub/__init__.py
+++ b/rwx/grub/__init__.py
@@ -1,3 +1,5 @@
+"""Wrap GRUB commands."""
+
 import cmd
 
 import ps
@@ -24,6 +26,7 @@ def make_image(
     memdisk_path: str,
     pubkey_path: str | None = None,
 ) -> None:
+    """Make a binary bootable image."""
     args = [
         ("grub-mkimage",),
         ("--compress", COMPRESSION),
diff --git a/rwx/prj/__init__.py b/rwx/prj/__init__.py
index 227a686..6a3e059 100644
--- a/rwx/prj/__init__.py
+++ b/rwx/prj/__init__.py
@@ -1,8 +1,13 @@
+"""Handle projects."""
+
 from os import path
 
 
 class Project:
+    """Parent class for any type of project."""
+
     def __init__(self, file_path: str) -> None:
+        """Set file, root & name."""
         self.file: str = path.realpath(file_path)
         self.root: str = path.dirname(self.file)
         self.name: str = path.basename(self.root)
diff --git a/rwx/prj/sphinx.py b/rwx/prj/sphinx.py
index afa0901..13252f8 100644
--- a/rwx/prj/sphinx.py
+++ b/rwx/prj/sphinx.py
@@ -9,10 +9,14 @@ from rwx.prj import Project
 
 
 class SphinxProject(Project):
+    """Child class for a project based on Sphinx."""
+
     def __init__(self, file_path: str) -> None:
+        """Call the parent constructor."""
         super().__init__(file_path)
 
     def build(self) -> None:
+        """Build the project."""
         output_root: str = path.join(self.root, "out")
         wipe(output_root)
         arguments: list[str] = [