diff --git a/src/mcp_synology_container/cli.py b/src/mcp_synology_container/cli.py
index 7471040..1e57aac 100644
--- a/src/mcp_synology_container/cli.py
+++ b/src/mcp_synology_container/cli.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import asyncio
+import contextlib
 import json
 import logging
 import sys
@@ -144,10 +145,8 @@ async def _run_setup() -> None:
                 client.sid = sid
                 click.echo(click.style("Login successful!", fg="green"))
                 # Logout cleanly
-                try:
+                with contextlib.suppress(SynologyError):
                     await client.request("SYNO.API.Auth", "logout", version=6, params={})
-                except SynologyError:
-                    pass
             else:
                 click.echo(click.style("Login failed: no session ID returned.", fg="red"), err=True)
                 sys.exit(1)
diff --git a/src/mcp_synology_container/modules/compose.py b/src/mcp_synology_container/modules/compose.py
index bc41f61..f0b02af 100644
--- a/src/mcp_synology_container/modules/compose.py
+++ b/src/mcp_synology_container/modules/compose.py
@@ -268,7 +268,7 @@ def register_compose(mcp: FastMCP, config: AppConfig, client: DsmClient) -> None
         # Determine previous value and build description
         old_value: str | None = None
         if isinstance(env_list, list):
-            for i, entry in enumerate(env_list):
+            for entry in env_list:
                 if isinstance(entry, str) and entry.startswith(f"{var_name}="):
                     old_value = entry.split("=", 1)[1]
                     break
@@ -325,8 +325,9 @@ def register_compose(mcp: FastMCP, config: AppConfig, client: DsmClient) -> None
         except Exception as e:
             return f"Error writing compose file: {e}"
 
+        verb = "Updated" if action == "update" else "Added"
         return (
-            f"{'Updated' if action == 'update' else 'Added'} env var in '{service_name}' ({project_name}):\n"
+            f"{verb} env var in '{service_name}' ({project_name}):\n"
             f"  {var_name}={var_value}\n\n"
             f"Tip: Run redeploy_project('{project_name}', confirmed=True) to apply the change."
         )
diff --git a/src/mcp_synology_container/modules/images.py b/src/mcp_synology_container/modules/images.py
index 386ffdf..a32b9fb 100644
--- a/src/mcp_synology_container/modules/images.py
+++ b/src/mcp_synology_container/modules/images.py
@@ -233,8 +233,10 @@ def register_images(mcp: FastMCP, config: AppConfig, client: DsmClient) -> None:
             )
 
         if in_use_stopped:
+            stopped_name = in_use_stopped[0]
             return (
-                f"Cannot delete '{display_name}': image is used by stopped container '{in_use_stopped[0]}'.\n"
+                f"Cannot delete '{display_name}': image is used by stopped container "
+                f"'{stopped_name}'.\n"
                 f"Delete the container first or run system_prune to clean up stopped containers."
             )
 
diff --git a/tests/test_auth.py b/tests/test_auth.py
index fa4ec30..c2a467f 100644
--- a/tests/test_auth.py
+++ b/tests/test_auth.py
@@ -35,9 +35,11 @@ def test_resolve_credentials_no_credentials(monkeypatch):
     config = make_config()
     auth = AuthManager(config)
 
-    with patch("keyring.get_password", return_value=None):
-        with pytest.raises(AuthenticationError, match="No credentials found"):
-            auth.resolve_credentials()
+    with (
+        patch("keyring.get_password", return_value=None),
+        pytest.raises(AuthenticationError, match="No credentials found"),
+    ):
+        auth.resolve_credentials()
 
 
 def test_resolve_credentials_from_keyring(monkeypatch):
@@ -124,9 +126,11 @@ async def test_login_2fa_required():
     mock_client = AsyncMock()
     mock_client.request.side_effect = SynologyError("2FA required", code=403)
 
-    with patch.object(auth, "resolve_credentials", return_value=("user", "pass", None)):
-        with pytest.raises(AuthenticationError, match="2FA is required"):
-            await auth.login(mock_client)
+    with (
+        patch.object(auth, "resolve_credentials", return_value=("user", "pass", None)),
+        pytest.raises(AuthenticationError, match="2FA is required"),
+    ):
+        await auth.login(mock_client)
 
 
 @pytest.mark.asyncio
@@ -137,9 +141,11 @@ async def test_login_no_sid_returned():
     mock_client = AsyncMock()
     mock_client.request.return_value = {}  # No 'sid' key
 
-    with patch.object(auth, "resolve_credentials", return_value=("user", "pass", None)):
-        with pytest.raises(AuthenticationError, match="no session ID"):
-            await auth.login(mock_client)
+    with (
+        patch.object(auth, "resolve_credentials", return_value=("user", "pass", None)),
+        pytest.raises(AuthenticationError, match="no session ID"),
+    ):
+        await auth.login(mock_client)
 
 
 @pytest.mark.asyncio