diff --git a/napalm_openwrt/config_mixin.py b/napalm_openwrt/config_mixin.py
index 9559a96..9c8f26d 100644
--- a/napalm_openwrt/config_mixin.py
+++ b/napalm_openwrt/config_mixin.py
@@ -91,7 +91,8 @@ class OpenWrtConfigMixin(ConfigLifecycleMixin):
         """
         if self._backup_config is None:
             raise CommandErrorException(
-                "No backup configuration available – commit_config has not been called in this session."
+                "No backup configuration available – "
+                "commit_config has not been called in this session."
             )
 
         escaped = self._backup_config.replace("'", "'\\''")
diff --git a/napalm_openwrt/system_mixin.py b/napalm_openwrt/system_mixin.py
index d302d72..63b0b9b 100644
--- a/napalm_openwrt/system_mixin.py
+++ b/napalm_openwrt/system_mixin.py
@@ -12,9 +12,12 @@
 
 from __future__ import annotations
 
+import logging
 import re
 from typing import Any
 
+logger = logging.getLogger(__name__)
+
 #: Printed after a command so its exit status survives the shell session.
 _RC_MARKER = "__OWRT_RC="
 _RC_RE = re.compile(rf"^{_RC_MARKER}(\d+)\s*$", re.MULTILINE)
@@ -30,7 +33,10 @@ def _split_status(raw: str) -> tuple[str, int | None]:
 
 
 class OpenWrtSystemMixin:
-    """Mixin providing system-level NAPALM getters (environment, NTP, SNMP, users, services, updates, device actions)."""
+    """Mixin providing system-level NAPALM getters.
+
+    Environment, NTP, SNMP, users, services, updates and device actions.
+    """
 
     def get_environment(self) -> dict[str, Any]:
         """Return device environment data (CPU, memory).
@@ -39,7 +45,8 @@ class OpenWrtSystemMixin:
         Memory from ``/proc/meminfo``.
         """
         cpu_out = self._send_command(
-            "awk '/^cpu /{idle1=$5; total1=$2+$3+$4+$5+$6+$7+$8} END{print (1-(idle1/total1))*100}' /proc/stat"
+            "awk '/^cpu /{idle1=$5; total1=$2+$3+$4+$5+$6+$7+$8} "
+            "END{print (1-(idle1/total1))*100}' /proc/stat"
         )
         mem_out = self._send_command("cat /proc/meminfo")
 
@@ -250,7 +257,7 @@ class OpenWrtSystemMixin:
             if uci_comm:
                 community = uci_comm
         except Exception:
-            pass
+            logger.debug("snmpd community: ignored", exc_info=True)
 
         return SNMPConfigDict(running=True, community=community, port=161, version="2c")
 
diff --git a/napalm_openwrt/wireless_mixin.py b/napalm_openwrt/wireless_mixin.py
index 5e5812b..d2d0e0e 100644
--- a/napalm_openwrt/wireless_mixin.py
+++ b/napalm_openwrt/wireless_mixin.py
@@ -12,9 +12,12 @@
 
 from __future__ import annotations
 
+import logging
 import re
 from typing import Any
 
+logger = logging.getLogger(__name__)
+
 
 class OpenWrtWirelessMixin:
     """Mixin providing wireless/radio NAPALM getters."""
@@ -155,7 +158,8 @@ class OpenWrtWirelessMixin:
                 if vlan is not None:
                     net_vlan[iface] = vlan
         except Exception:
-            pass  # Non-fatal: VLAN info is optional enrichment
+            # Non-fatal: VLAN info is optional enrichment.
+            logger.debug("network VLANs: ignored", exc_info=True)
 
         # Build result; group entries with the same SSID name, merging bands
         result: dict[str, Any] = {}
diff --git a/tests/unit/test_driver.py b/tests/unit/test_driver.py
index 77ffb82..a5f9b75 100644
--- a/tests/unit/test_driver.py
+++ b/tests/unit/test_driver.py
@@ -911,7 +911,7 @@ class TestGetRouteTo:
 
     def test_required_keys(self, driver):
         driver._send_command = lambda cmd, **kw: IP_ROUTE_SHOW
-        for prefix, routes in driver.get_route_to().items():
+        for _prefix, routes in driver.get_route_to().items():
             for route in routes:
                 assert set(route.keys()) >= {
                     "protocol",
diff --git a/tests/unit/test_ssh_host_key.py b/tests/unit/test_ssh_host_key.py
index 7250df4..03ffddd 100644
--- a/tests/unit/test_ssh_host_key.py
+++ b/tests/unit/test_ssh_host_key.py
@@ -76,7 +76,7 @@ def test_a_changed_key_is_refused():
         try:
             raise paramiko.BadHostKeyException("10.0.0.8", SERVER_KEY, OTHER_KEY)
         except paramiko.SSHException as exc:  # what netmiko does with it
-            raise NetmikoTimeoutException(f"A paramiko SSHException occurred: {exc}")
+            raise NetmikoTimeoutException(f"A paramiko SSHException occurred: {exc}") from exc
 
     driver = _driver(seen, SshHostKey.of(OTHER_KEY))
     with patch(HANDLER, side_effect=refuse):