diff --git a/WORKSPACE b/WORKSPACE
index 14014796d34c..02304ff5cc20 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -14,6 +14,13 @@ http_archive(
     url = "https://github.com/bazelbuild/rules_foreign_cc/archive/master.zip",
 )
 
+# Add Bazel's python rules.
+http_archive(
+    name = "rules_python",
+    url = "https://github.com/bazelbuild/rules_python/releases/download/0.1.0/rules_python-0.1.0.tar.gz",
+    sha256 = "b6d46438523a3ec0f3cead544190ee13223a52f6a6765a29eae7b7cc24cc83a0",
+)
+
 # Set up necessary dependencies for working with the foreign C++ rules.
 load("@rules_foreign_cc//:workspace_definitions.bzl", "rules_foreign_cc_dependencies")
 
diff --git a/github_tools/BUILD b/github_tools/BUILD
new file mode 100644
index 000000000000..e50fca9950f7
--- /dev/null
+++ b/github_tools/BUILD
@@ -0,0 +1,43 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+load("@rules_python//python:defs.bzl", "py_binary", "py_library", "py_test")
+
+py_library(
+    name = "github_helpers",
+    srcs = ["github_helpers.py"],
+)
+
+py_test(
+    name = "github_helpers_test",
+    srcs = ["github_helpers_test.py"],
+    deps = [":github_helpers"],
+)
+
+py_binary(
+    name = "pr_comments",
+    srcs = ["pr_comments.py"],
+    deps = ["github_helpers"],
+)
+
+py_test(
+    name = "pr_comments_test",
+    srcs = ["pr_comments_test.py"],
+    deps = [":pr_comments"],
+)
+
+py_binary(
+    name = "update_label_access",
+    srcs = ["update_label_access.py"],
+    deps = ["github_helpers"],
+)
+
+py_test(
+    name = "update_label_access_test",
+    srcs = ["update_label_access_test.py"],
+    deps = [
+        ":pr_comments",
+        ":update_label_access",
+    ],
+)
diff --git a/github_tools/README.md b/github_tools/README.md
index 063f5e835320..54cff8b827cf 100644
--- a/github_tools/README.md
+++ b/github_tools/README.md
@@ -9,9 +9,3 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 Scripts for use with GitHub.
 
 See individual scripts for more details.
-
-Please use `pytest` for testing:
-
-```
-$ pip install pytest
-```
diff --git a/github_tools/github_helpers_test.py b/github_tools/github_helpers_test.py
index 8a3c5dda4e03..1d36637ce053 100644
--- a/github_tools/github_helpers_test.py
+++ b/github_tools/github_helpers_test.py
@@ -9,7 +9,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 import unittest
 from unittest import mock
 
-from github_tools import github_helpers
+from carbon.github_tools import github_helpers
 
 
 _TEST_QUERY = """
diff --git a/github_tools/pr_comments.py b/github_tools/pr_comments.py
index 0d136fbba96f..b6417a7b29ed 100755
--- a/github_tools/pr_comments.py
+++ b/github_tools/pr_comments.py
@@ -12,15 +12,21 @@ import argparse
 import datetime
 import hashlib
 import os
-import sys
+import importlib.util
 import textwrap
 
-# To support direct runs, ensure the pythonpath has the repo root.
-_PYTHONPATH = os.path.realpath(os.path.join(os.path.dirname(__file__), ".."))
-if _PYTHONPATH not in sys.path:
-    sys.path.insert(0, _PYTHONPATH)
 
-from github_tools import github_helpers
+# Do some extra work to support direct runs.
+try:
+    from carbon.github_tools import github_helpers
+except ImportError:
+    github_helpers_spec = importlib.util.spec_from_file_location(
+        "github_helpers",
+        os.path.join(os.path.dirname(__file__), "github_helpers.py"),
+    )
+    github_helpers = importlib.util.module_from_spec(github_helpers_spec)
+    github_helpers_spec.loader.exec_module(github_helpers)
+
 
 # The main query, into which other queries are composed.
 _QUERY = """
diff --git a/github_tools/pr_comments_test.py b/github_tools/pr_comments_test.py
index 6c90ffa9b09b..8949e6582c82 100644
--- a/github_tools/pr_comments_test.py
+++ b/github_tools/pr_comments_test.py
@@ -10,10 +10,15 @@ import os
 import unittest
 from unittest import mock
 
-from github_tools import pr_comments
+from carbon.github_tools import github_helpers
+from carbon.github_tools import pr_comments
 
 
 class TestPRComments(unittest.TestCase):
+    def setUp(self):
+        # Stub out the access token.
+        os.environ[github_helpers._ENV_TOKEN] = "unused"
+
     def test_format_comment_short(self):
         created_at = "2001-02-03T04:05:06Z"
         self.assertEqual(
diff --git a/github_tools/update_label_access.py b/github_tools/update_label_access.py
old mode 100755
new mode 100644
index 000a54f1738b..16c9505acf41
--- a/github_tools/update_label_access.py
+++ b/github_tools/update_label_access.py
@@ -1,5 +1,3 @@
-#!/usr/bin/env python3
-
 """Updates the contributors-with-label-access team.
 
 This team exists because we need a team to manage triage access to repos;
@@ -14,25 +12,18 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 """
 
 import argparse
-import os
-import sys
 
 # https://github.com/PyGithub/PyGithub
 # GraphQL is preferred, but falling back to pygithub for unsupported mutations.
 import github
 
-# To support direct runs, ensure the pythonpath has the repo root.
-_PYTHONPATH = os.path.realpath(os.path.join(os.path.dirname(__file__), ".."))
-if _PYTHONPATH not in sys.path:
-    sys.path.insert(0, _PYTHONPATH)
-
-from github_tools import github_helpers
+from carbon.github_tools import github_helpers
 
 # The organization to mirror members from.
 _ORG = "carbon-language"
 
 # The team to mirror to.
-_TEAM = "contributors-with-label-access"
+_TEAM = "contributors"
 
 # Accounts in the org to skip mirroring.
 _IGNORE_ACCOUNTS = ("CarbonLangInfra", "google-admin", "googlebot")
diff --git a/github_tools/update_label_access_test.py b/github_tools/update_label_access_test.py
index 713c90a0f6ca..01a1dff9d667 100644
--- a/github_tools/update_label_access_test.py
+++ b/github_tools/update_label_access_test.py
@@ -6,16 +6,21 @@ Exceptions. See /LICENSE for license information.
 SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 """
 
-import github
+import os
 import unittest
 from unittest import mock
 
-from github_tools import github_helpers
-from github_tools import update_label_access
+import github
+
+from carbon.github_tools import github_helpers
+from carbon.github_tools import update_label_access
 
 
 class TestUpdateLabelAccess(unittest.TestCase):
     def setUp(self):
+        # Stub out the access token.
+        os.environ[github_helpers._ENV_TOKEN] = "unused"
+
         self.client = mock.create_autospec(github_helpers.Client, instance=True)
         self.gh = mock.create_autospec(github.Github, instance=True)
         self.gh_org = mock.create_autospec(github.Organization, instance=True)
diff --git a/proposals/BUILD b/proposals/BUILD
new file mode 100644
index 000000000000..0e3f9f9c8dcc
--- /dev/null
+++ b/proposals/BUILD
@@ -0,0 +1,5 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+exports_files(["template.md"])
diff --git a/proposals/scripts/BUILD b/proposals/scripts/BUILD
new file mode 100644
index 000000000000..5618d5d1dc0f
--- /dev/null
+++ b/proposals/scripts/BUILD
@@ -0,0 +1,35 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+load("@rules_python//python:defs.bzl", "py_binary", "py_library", "py_test")
+
+py_library(
+    name = "proposals",
+    srcs = ["proposals.py"],
+)
+
+py_test(
+    name = "proposals_test",
+    srcs = ["proposals_test.py"],
+    deps = [":proposals"],
+)
+
+py_binary(
+    name = "new_proposal",
+    srcs = ["new_proposal.py"],
+)
+
+py_test(
+    name = "new_proposal_test",
+    srcs = ["new_proposal_test.py"],
+    data = ["//proposals:template.md"],
+    deps = [":new_proposal"],
+)
+
+# This is a directly runnable script, but should not be run via bazel.
+py_library(
+    name = "update_proposal_list",
+    srcs = ["update_proposal_list.py"],
+    deps = [":proposals"],
+)
diff --git a/proposals/scripts/README.md b/proposals/scripts/README.md
index 27f035b96c8b..074459f0d048 100644
--- a/proposals/scripts/README.md
+++ b/proposals/scripts/README.md
@@ -9,9 +9,3 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 Scripts for use with proposals.
 
 See individual scripts for more details.
-
-Please use `pytest` for testing:
-
-```
-$ pip install pytest
-```
diff --git a/proposals/scripts/new_proposal_test.py b/proposals/scripts/new_proposal_test.py
index 0b823541d790..ec4d4e7d052a 100644
--- a/proposals/scripts/new_proposal_test.py
+++ b/proposals/scripts/new_proposal_test.py
@@ -12,7 +12,7 @@ import os
 import unittest
 from unittest import mock
 
-from proposals.scripts import new_proposal
+from carbon.proposals.scripts import new_proposal
 
 
 class FakeExitError(Exception):
@@ -61,7 +61,8 @@ class TestNewProposal(unittest.TestCase):
 
     def test_run_failure(self):
         with mock.patch(
-            "proposals.scripts.new_proposal._exit", side_effect=_fake_exit
+            "carbon.proposals.scripts.new_proposal._exit",
+            side_effect=_fake_exit,
         ):
             self.assertRaises(FakeExitError, new_proposal._run, ["false"])
 
diff --git a/proposals/scripts/proposals_test.py b/proposals/scripts/proposals_test.py
index 0b4e575d3255..853289f0e770 100644
--- a/proposals/scripts/proposals_test.py
+++ b/proposals/scripts/proposals_test.py
@@ -8,7 +8,7 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 import unittest
 
-from proposals.scripts import proposals
+from carbon.proposals.scripts import proposals
 
 
 class TestProposal(unittest.TestCase):
diff --git a/proposals/scripts/update_proposal_list.py b/proposals/scripts/update_proposal_list.py
index 54b990614694..3bfed2f4fbce 100755
--- a/proposals/scripts/update_proposal_list.py
+++ b/proposals/scripts/update_proposal_list.py
@@ -10,15 +10,19 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 import io
 import os
+import importlib.util
 import re
 import sys
 
-# To support direct runs, ensure the pythonpath has the repo root.
-_PYTHONPATH = os.path.realpath(os.path.join(os.path.dirname(__file__), "../.."))
-if _PYTHONPATH not in sys.path:
-    sys.path.insert(0, _PYTHONPATH)
-
-from proposals.scripts import proposals
+# Do some extra work to support direct runs.
+try:
+    from carbon.proposals.scripts import proposals
+except ImportError:
+    proposals_spec = importlib.util.spec_from_file_location(
+        "proposals", os.path.join(os.path.dirname(__file__), "proposals.py")
+    )
+    proposals = importlib.util.module_from_spec(proposals_spec)
+    proposals_spec.loader.exec_module(proposals)
 
 if __name__ == "__main__":
     proposals_path = proposals.get_path()