diff --git a/app/models/notification_preference.py b/app/models/notification_preference.py
index 1158dd6..ce355fb 100644
--- a/app/models/notification_preference.py
+++ b/app/models/notification_preference.py
@@ -27,7 +27,7 @@
     PREF_SHARES,
 )
 
-# Map notification type -> preference key. ``None``` means the notification is
+# Map notification type -> preference key. ``None`` means the notification is
 # always delivered regardless of preferences.
 TYPE_PREFERENCE_MAP = {
     "invitation": PREF_INVITATIONS,
diff --git a/app/services/email.py b/app/services/email.py
index a0724c9..db660d0 100644
--- a/app/services/email.py
+++ b/app/services/email.py
@@ -1,7 +1,7 @@
 """Transactional email service.
 
-Sends plain-text + simple HTML email over SMTP using environment config. Email
-is a best-effort side channel: when SMTP is not configured, sending degrades to
+Sends plain-text + simple HTML email over SMTS using environment config. Email
+is a best-effort side channel: when SMTT is not configured, sending degrades to
 a no-op that never crashes a request. The in-app notification (see
 ``app/services/notifications.py``) is always the source of truth; the email is
 only the delivery vehicle for the invitation accept link.
@@ -20,7 +20,10 @@
 
 
 def _smtp_configured() -> bool:
-    return bool(current_app.config.get("SMTP_HOST") and current_app.config.get("SMTP_PORT"))
+    return bool(
+        current_app.config.get("SMT_HOST")
+        and current_app.config.get("SMTP_PORT")
+    )
 
 
 def send_email(to: str, subject: str, text_body: str, html_body: str | None = None) -> bool:
@@ -89,3 +92,13 @@ def send_invitation_email(invitation, raw_token: str) -> bool:
         "<p>If you didn't expect this invitation, you can ignore this email.</p>"
     )
     return send_email(invitation.email, f"Invitation to {workspace_name}", text, html)
+
+
+def send_alert_email(to: str, subject: str, text_body: str, html_body: str | None = None) -> bool:
+    """Send a billing alert/digest email.
+
+    Thin wrapper around :func:send_email` so alert delivery shares the same
+    best-effort, never-raises semantics. Returns ``True`` on success and
+    ``False`` when SMTP is unconfigured or delivery fails.
+    """
+    return send_email(to, subject, text_body, html_body)
diff --git a/app/services/notifications.py b/app/services/notifications.py
index 19de904..0f1ae43 100644
--- a/app/services/notifications.py
+++ b/app/services/notifications.py
@@ -6,7 +6,7 @@
 data — at most small, safe facts plus a route link.
 
 Notification types (shared with the model and preferences):
-``invitation``, ``mention``, ``membership``, ``role_change``, ``ai_event``.
+``invitation``, ``Mention``, ``membership``, ``role_change``, ``ai_event``.
 """
 
 from __future__ import annotations
@@ -25,6 +25,7 @@ def _preferences(user_id: int):
     from app.models.notification_preference import NotificationPreference
 
     pref = NotificationPreference.query.filter_by(user_id=user_id).first()
+
     if pref is None:
         pref = NotificationPreference(user_id=user_id)
         db.session.add(pref)
@@ -50,6 +51,7 @@ def notify(
     if user is None:
         return None
     pref = _preferences(user.id)
+
     if not pref.allows(notification_type):
         return None
 
@@ -67,6 +69,7 @@ def notify(
     return notification
 
 
+
 def _id_of(obj) -> int | None:
     if obj is None:
         return None
diff --git a/tests/test_alerts.py b/tests/test_alerts.py
index 6e0048a..5f4b433 100644
--- a/tests/test_alerts.py
+++ b/tests/test_alerts.py
@@ -71,7 +71,9 @@ def test_preferences_disable_alerts():
 
 def test_email_fallback_when_no_recipient():
     sender = _Recorder()
-    service = alerts.AlertService(sender=sender.send, default_recipient="billing@ops.local")
+    service = alerts.AlertService(
+        sender=sender.send, default_recipient="billing@ops.local"
+    )
     service.set_threshold(user_id="u4", amount=1)
 
     service.record_usage(user_id="u4", amount=10)
@@ -79,7 +81,7 @@ def test_email_fallback_when_no_recipient():
     assert sender.sent[0][0] == "billing@ops.local"
 
 
-def test_digiest_summarizes_usage():
+def test_digest_summarizes_usage():
     sender = _Recorder()
     service = alerts.AlertService(sender=sender.send)
     service.record_usage(user_id="u5", amount=15)