diff --git a/pw_tokenizer/py/BUILD.gn b/pw_tokenizer/py/BUILD.gn
index b2d19e9..a5ab5c9 100644
--- a/pw_tokenizer/py/BUILD.gn
+++ b/pw_tokenizer/py/BUILD.gn
@@ -1,4 +1,4 @@
-# Copyright 2020 The Pigweed Authors
+# Copyright 2021 The Pigweed Authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may not
 # use this file except in compliance with the License. You may obtain a copy of
@@ -59,6 +59,13 @@
   pylintrc = "$dir_pigweed/.pylintrc"
 }
 
+# This setup.py may be used to install pw_tokenizer without GN. It does not
+# include the pw_tokenizer.proto subpackage, since it contains a generated
+# protobuf module.
+pw_python_script("setup") {
+  sources = [ "setup.py" ]
+}
+
 pw_proto_library("test_proto") {
   sources = [ "detokenize_proto_test.proto" ]
   deps = [ "..:proto" ]
diff --git a/pw_tokenizer/py/setup.py b/pw_tokenizer/py/setup.py
index 04680f1..eba125e 100644
--- a/pw_tokenizer/py/setup.py
+++ b/pw_tokenizer/py/setup.py
@@ -1,4 +1,4 @@
-# Copyright 2020 The Pigweed Authors
+# Copyright 2021 The Pigweed Authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may not
 # use this file except in compliance with the License. You may obtain a copy of
@@ -11,7 +11,12 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations under
 # the License.
-"""The pw_tokenizer package."""
+"""The pw_tokenizer package.
+
+Installing pw_tokenizer with this setup.py does not include the
+pw_tokenizer.proto package, since it contains a generated protobuf module. To
+access pw_tokenizer.proto, install pw_tokenizer from GN.
+"""
 
 import setuptools  # type: ignore
 
@@ -20,10 +25,9 @@
     version='0.0.1',
     author='Pigweed Authors',
     author_email='pigweed-developers@googlegroups.com',
-    description='Tools for decoding tokenized strings',
-    packages=setuptools.find_packages(),
+    description='Tools for working with tokenized strings',
+    packages=['pw_tokenizer'],
     package_data={'pw_tokenizer': ['py.typed']},
     zip_safe=False,
-    test_suite='setup.test_suite',
     extra_requires=['serial'],
 )