diff --git a/src/mcp_synology_container/cli.py b/src/mcp_synology_container/cli.py
index 9c652eb..7520513 100644
--- a/src/mcp_synology_container/cli.py
+++ b/src/mcp_synology_container/cli.py
@@ -43,8 +43,8 @@ def setup(verbose: bool) -> None:
 
 async def _run_setup() -> None:
     """Interactive setup flow."""
-    from mcp_synology_container.auth import AuthManager, AuthenticationError
-    from mcp_synology_container.config import AppConfig, ConnectionConfig, CONFIG_PATH, save_config
+    from mcp_synology_container.auth import AuthManager
+    from mcp_synology_container.config import CONFIG_PATH, AppConfig, ConnectionConfig, save_config
     from mcp_synology_container.dsm_client import DsmClient, SynologyError
 
     click.echo("=== mcp-synology-container setup ===\n")
@@ -198,7 +198,7 @@ def check(config_path: str | None, verbose: bool) -> None:
 
 async def _run_check(config_path: str | None) -> bool:
     """Run connectivity check. Returns True on success."""
-    from mcp_synology_container.auth import AuthManager, AuthenticationError
+    from mcp_synology_container.auth import AuthenticationError, AuthManager
     from mcp_synology_container.config import load_config
     from mcp_synology_container.dsm_client import DsmClient, SynologyError
 
diff --git a/src/mcp_synology_container/config.py b/src/mcp_synology_container/config.py
index 6e736f5..63e628a 100644
--- a/src/mcp_synology_container/config.py
+++ b/src/mcp_synology_container/config.py
@@ -12,7 +12,7 @@ from __future__ import annotations
 
 import logging
 import os
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from pathlib import Path
 from typing import Any
 
diff --git a/tests/test_auth.py b/tests/test_auth.py
index 6f8411e..fa4ec30 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -1,9 +1,10 @@
 """Tests for auth.py."""
 
-import pytest
-from unittest.mock import AsyncMock, MagicMock, patch
+from unittest.mock import AsyncMock, patch
 
-from mcp_synology_container.auth import AuthManager, AuthenticationError
+import pytest
+
+from mcp_synology_container.auth import AuthenticationError, AuthManager
 from mcp_synology_container.config import AppConfig, ConnectionConfig
 
 
diff --git a/tests/test_config.py b/tests/test_config.py
index fe2a4b0..2dff42c 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -1,14 +1,14 @@
 """Tests for config.py."""
 
+
 import pytest
 import yaml
-from pathlib import Path
 
 from mcp_synology_container.config import (
     AppConfig,
     ConnectionConfig,
-    _validate_config,
     _merge_env_overrides,
+    _validate_config,
     load_config,
     save_config,
 )