diff --git a/github_rest_api/github.py b/github_rest_api/github.py
index a33d139..1a56a00 100644
--- a/github_rest_api/github.py
+++ b/github_rest_api/github.py
@@ -1,16 +1,45 @@
 """Simple wrapper of GitHub REST APIs."""
 
+import re
 from abc import ABCMeta, abstractmethod
 from base64 import b64encode
 from collections.abc import Sequence
 from enum import StrEnum
-from typing import Any, Callable
 from pathlib import Path
+from typing import Any, Callable
+
 import requests
 from nacl import encoding, public
 
 URL_API = "https://api.github.com"
 
+_SECRET_NAME_PATTERN = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*$")
+
+
+def _validate_secret_name(name: str) -> None:
+    """Validate a secret name against GitHub's naming rules.
+
+    GitHub rejects invalid secret names with a 422 response. Validating the
+    name client-side surfaces a clear error before the request is sent.
+
+    :param name: The name of the secret.
+    :raises ValueError: If the name is empty, starts with the reserved
+        ``GITHUB_`` prefix, starts with a digit, or contains characters other
+        than alphanumerics and underscores.
+    """
+    if not name:
+        raise ValueError("A secret name must not be empty.")
+    if name.upper().startswith("GITHUB_"):
+        raise ValueError(
+            f"Invalid secret name {name!r}: names must not start with the "
+            "reserved 'GITHUB_' prefix."
+        )
+    if not _SECRET_NAME_PATTERN.fullmatch(name):
+        raise ValueError(
+            f"Invalid secret name {name!r}: names may only contain alphanumeric "
+            "characters and underscores, and must not start with a digit."
+        )
+
 
 def _encrypt_secret(public_key: str, value: str) -> str:
     """Encrypt a secret value using a LibSodium sealed box.
@@ -354,6 +383,7 @@ def create_or_update_secret(
             automatically. Fetch it once and reuse it to avoid a redundant
             request when creating or updating multiple secrets.
         """
+        _validate_secret_name(name)
         if public_key is None:
             public_key = self.get_secret_public_key()
         return self._put(
@@ -549,6 +579,7 @@ def create_or_update_secret(
         :param selected_repository_ids: Repository IDs that can access the secret
             when visibility is `selected`.
         """
+        _validate_secret_name(name)
         if selected_repository_ids and visibility != SecretVisibility.SELECTED:
             raise ValueError(
                 "`selected_repository_ids` can only be provided when `visibility` is 'selected'."
diff --git a/github_rest_api/scripts/cargo/benchmark.py b/github_rest_api/scripts/cargo/benchmark.py
index b884405..19ea24b 100644
--- a/github_rest_api/scripts/cargo/benchmark.py
+++ b/github_rest_api/scripts/cargo/benchmark.py
@@ -1,18 +1,20 @@
 """Benchmark action using cargo criterion."""
 
-from typing import Callable
-import tempfile
-from pathlib import Path
 import datetime
 import shutil
 import subprocess as sp
+import tempfile
+from pathlib import Path
+from typing import Callable
+
 from dulwich import porcelain
+
 from ..utils import (
+    commit_benchmarks,
     config_git,
-    switch_branch,
-    push_branch,
     gen_temp_branch,
-    commit_benchmarks,
+    push_branch,
+    switch_branch,
 )
 
 
diff --git a/github_rest_api/scripts/cargo/profiling.py b/github_rest_api/scripts/cargo/profiling.py
index b55094c..94cf6e0 100644
--- a/github_rest_api/scripts/cargo/profiling.py
+++ b/github_rest_api/scripts/cargo/profiling.py
@@ -1,14 +1,16 @@
 """Utils for profiling Rust applications."""
 
-from typing import Iterable
-from pathlib import Path
-import time
 import datetime
 import subprocess as sp
+import time
+from pathlib import Path
+from typing import Iterable
+
 import psutil
-from .utils import build_project
-from ..utils import config_git, switch_branch, push_branch, commit_profiling
+
 from ...utils import partition
+from ..utils import commit_profiling, config_git, push_branch, switch_branch
+from .utils import build_project
 
 
 def launch_application(cmd: list[str]) -> int:
diff --git a/github_rest_api/scripts/container/build_container_images.py b/github_rest_api/scripts/container/build_container_images.py
index ae577a5..a57e176 100644
--- a/github_rest_api/scripts/container/build_container_images.py
+++ b/github_rest_api/scripts/container/build_container_images.py
@@ -1,16 +1,17 @@
 import argparse
-from collections.abc import Sequence
 import datetime
-from pathlib import Path
 import subprocess as sp
 import sys
+from collections.abc import Sequence
+from pathlib import Path
 from typing import cast
+
 import yaml
-from dulwich.repo import Repo
-from dulwich.refs import Ref
-from dulwich.objects import Commit
-from dulwich.errors import NotGitRepository
 from dulwich.diff_tree import tree_changes
+from dulwich.errors import NotGitRepository
+from dulwich.objects import Commit
+from dulwich.refs import Ref
+from dulwich.repo import Repo
 from tenacity import retry, stop_after_attempt, wait_exponential
 
 
diff --git a/github_rest_api/scripts/container/config_container.py b/github_rest_api/scripts/container/config_container.py
index 6c4829c..dfd4a17 100644
--- a/github_rest_api/scripts/container/config_container.py
+++ b/github_rest_api/scripts/container/config_container.py
@@ -1,11 +1,12 @@
 import argparse
 import json
 import shutil
+import subprocess as sp
 import sys
 import tomllib
-import tomli_w
 from pathlib import Path
-import subprocess as sp
+
+import tomli_w
 
 
 def config_docker(data_root: str = "/mnt/docker"):
diff --git a/github_rest_api/scripts/container/update_version_containerfile.py b/github_rest_api/scripts/container/update_version_containerfile.py
index 94418f1..1f50faa 100644
--- a/github_rest_api/scripts/container/update_version_containerfile.py
+++ b/github_rest_api/scripts/container/update_version_containerfile.py
@@ -1,13 +1,15 @@
 import argparse
 import datetime
 import os
+import re
 import sys
 from pathlib import Path
-import re
+
 from dulwich import porcelain
+from requests.exceptions import HTTPError
+
 from github_rest_api import Repository
 from github_rest_api.utils import next_minor_or_strip_patch
-from requests.exceptions import HTTPError
 
 
 def parse_latest_version(repo: str) -> str:
diff --git a/github_rest_api/scripts/github/add_github_repo.py b/github_rest_api/scripts/github/add_github_repo.py
index 02ce0fa..aedb374 100644
--- a/github_rest_api/scripts/github/add_github_repo.py
+++ b/github_rest_api/scripts/github/add_github_repo.py
@@ -7,9 +7,10 @@
 import sys
 from collections.abc import Sequence
 from pathlib import Path
+
 from dulwich import porcelain
 
-from github_rest_api import User, Organization
+from github_rest_api import Organization, User
 
 
 def _validate_repo(repo: str) -> None:
diff --git a/github_rest_api/scripts/github/create_pull_request.py b/github_rest_api/scripts/github/create_pull_request.py
index 72ddf20..2e562d7 100644
--- a/github_rest_api/scripts/github/create_pull_request.py
+++ b/github_rest_api/scripts/github/create_pull_request.py
@@ -2,9 +2,10 @@
 The branch is updated (using dev) before creating the PR.
 """
 
-from argparse import ArgumentParser, Namespace
 import os
 import sys
+from argparse import ArgumentParser, Namespace
+
 from github_rest_api import Repository
 from github_rest_api.utils import compile_patterns
 
diff --git a/github_rest_api/scripts/github/release_on_github.py b/github_rest_api/scripts/github/release_on_github.py
index d16883f..b9a4783 100644
--- a/github_rest_api/scripts/github/release_on_github.py
+++ b/github_rest_api/scripts/github/release_on_github.py
@@ -1,9 +1,10 @@
+import argparse
+import getpass
 import os
 import re
 import sys
-import argparse
-import getpass
 from pathlib import Path
+
 from github_rest_api import Repository
 from github_rest_api.scripts.utils import (
     find_project_root,
diff --git a/github_rest_api/scripts/github/remove_branch.py b/github_rest_api/scripts/github/remove_branch.py
index 1885c69..9fd1a56 100644
--- a/github_rest_api/scripts/github/remove_branch.py
+++ b/github_rest_api/scripts/github/remove_branch.py
@@ -1,7 +1,8 @@
 import argparse
+import datetime
 import re
 import sys
-import datetime
+
 from github_rest_api import Repository
 
 
diff --git a/github_rest_api/scripts/utils.py b/github_rest_api/scripts/utils.py
index ebbf68a..b0448fe 100644
--- a/github_rest_api/scripts/utils.py
+++ b/github_rest_api/scripts/utils.py
@@ -1,10 +1,11 @@
 """Util functions for GitHub actions."""
 
+import random
 import tomllib
-from typing import Any, Iterable
-from pathlib import Path
 from collections.abc import Sequence
-import random
+from pathlib import Path
+from typing import Any, Iterable
+
 from dulwich import porcelain
 from dulwich.repo import Repo
 
diff --git a/github_rest_api/utils.py b/github_rest_api/utils.py
index 6bd4c27..a07f3f2 100644
--- a/github_rest_api/utils.py
+++ b/github_rest_api/utils.py
@@ -1,8 +1,8 @@
 """Some generally useful util functions."""
 
-from collections.abc import Sequence
-from itertools import tee, filterfalse
 import re
+from collections.abc import Sequence
+from itertools import filterfalse, tee
 
 
 def partition(pred, iterable):
diff --git a/pyproject.toml b/pyproject.toml
index 33e062d..c8255b2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ requires = [ "hatchling" ]
 
 [project]
 name = "github-rest-api"
-version = "0.42.0"
+version = "0.42.1"
 description = "Simple wrapper of GitHub REST APIs."
 readme = "README.md"
 authors = [ { name = "Ben Du", email = "longendu@yahoo.com" } ]
@@ -41,3 +41,8 @@ dev = [
   "ruff>=0.14.10",
   "ty>=0.0.8",
 ]
+
+[tool.ruff.lint]
+# select the 'I' rule set for import sorting
+extend-select = ["I"]
+
diff --git a/tests/test_build_container_images.py b/tests/test_build_container_images.py
index f1df51d..5072886 100644
--- a/tests/test_build_container_images.py
+++ b/tests/test_build_container_images.py
@@ -1,5 +1,6 @@
 from pathlib import Path
 from unittest.mock import patch
+
 from github_rest_api.scripts.container.build_container_images import (
     has_relevant_changes,
 )
diff --git a/tests/test_github.py b/tests/test_github.py
index da6a350..acc69ff 100644
--- a/tests/test_github.py
+++ b/tests/test_github.py
@@ -1,7 +1,16 @@
 import os
 from base64 import b64decode
+
+import pytest
 from nacl import encoding, public
-from github_rest_api.github import User, Organization, Repository, _encrypt_secret
+
+from github_rest_api.github import (
+    Organization,
+    Repository,
+    User,
+    _encrypt_secret,
+    _validate_secret_name,
+)
 
 TOKEN = os.environ.get("GITHUB_TOKEN", "")
 
@@ -14,6 +23,32 @@ def test_encrypt_secret_roundtrip():
     assert decrypted == b"s3cret-value"
 
 
+@pytest.mark.parametrize(
+    "name",
+    ["MY_SECRET", "_underscore", "Token123", "a"],
+)
+def test_validate_secret_name_valid(name):
+    _validate_secret_name(name)
+
+
+@pytest.mark.parametrize(
+    "name",
+    [
+        "",
+        "GITHUB_ACTIONS",
+        "GITHUB_TOKEN",
+        "github_token",
+        "GitHub_Token",
+        "1SECRET",
+        "MY-SECRET",
+        "MY SECRET",
+    ],
+)
+def test_validate_secret_name_invalid(name):
+    with pytest.raises(ValueError):
+        _validate_secret_name(name)
+
+
 def test_user_get_repositories():
     user = User(TOKEN, "dclong")
     repos = user.get_repositories()
diff --git a/tests/test_release_on_github.py b/tests/test_release_on_github.py
index ec3edb1..660e9fe 100644
--- a/tests/test_release_on_github.py
+++ b/tests/test_release_on_github.py
@@ -1,6 +1,8 @@
 from pathlib import Path
 from unittest.mock import patch
+
 import pytest
+
 from github_rest_api.scripts.github.release_on_github import _get_release_tag
 
 ROOT = Path(".")
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 3db890e..f9e249d 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,4 +1,5 @@
 import pytest
+
 from github_rest_api.utils import next_minor_or_strip_patch, strip_patch_version
 
 
diff --git a/uv.lock b/uv.lock
index 3bd5cc2..007e4df 100644
--- a/uv.lock
+++ b/uv.lock
@@ -223,7 +223,7 @@ wheels = [
 
 [[package]]
 name = "github-rest-api"
-version = "0.41.0"
+version = "0.42.1"
 source = { editable = "." }
 dependencies = [
     { name = "dulwich" },