diff --git a/outlook_web/controllers/settings.py b/outlook_web/controllers/settings.py
index c130a8e..8ec9075 100644
--- a/outlook_web/controllers/settings.py
+++ b/outlook_web/controllers/settings.py
@@ -123,7 +123,11 @@ def api_update_settings() -> Any:
     if "external_api_key" in data:
         new_external_api_key = str(data["external_api_key"] or "").strip()
         existing_external_api_key = settings_repo.get_external_api_key()
-        if new_external_api_key and existing_external_api_key and new_external_api_key == _mask_secret_value(existing_external_api_key):
+        if (
+            new_external_api_key
+            and existing_external_api_key
+            and new_external_api_key == _mask_secret_value(existing_external_api_key)
+        ):
             updated.append("对外 API Key（未变更）")
         elif new_external_api_key:
             encrypted_key = encrypt_data(new_external_api_key)
diff --git a/outlook_web/db.py b/outlook_web/db.py
index 5e98e6e..284fa68 100644
--- a/outlook_web/db.py
+++ b/outlook_web/db.py
@@ -423,12 +423,10 @@ def init_db(database_path: Optional[str] = None):
         )
 
         # PRD-00008 / FD-00008：对外开放 API Key（默认空，建议加密存储）
-        cursor.execute(
-            """
+        cursor.execute("""
             INSERT OR IGNORE INTO settings (key, value)
             VALUES ('external_api_key', '')
-            """
-        )
+            """)
 
         # 初始化刷新配置
         cursor.execute("""
diff --git a/outlook_web/services/external_api.py b/outlook_web/services/external_api.py
index 4c84ce8..c67631f 100644
--- a/outlook_web/services/external_api.py
+++ b/outlook_web/services/external_api.py
@@ -137,21 +137,13 @@ def _build_message_summary(email_addr: str, item: Dict[str, Any], *, method: str
     subject = str(item.get("subject") or "无主题")
 
     created_at_raw = (
-        item.get("receivedDateTime")
-        or item.get("date")
-        or item.get("created_at")
-        or item.get("received_at")
-        or ""
+        item.get("receivedDateTime") or item.get("date") or item.get("created_at") or item.get("received_at") or ""
     )
     created_dt = _parse_datetime(str(created_at_raw))
     created_at, timestamp = _format_datetime(created_dt, str(created_at_raw))
 
     content_preview = str(
-        item.get("bodyPreview")
-        or item.get("body_preview")
-        or item.get("content_preview")
-        or item.get("bodyPreview")
-        or ""
+        item.get("bodyPreview") or item.get("body_preview") or item.get("content_preview") or item.get("bodyPreview") or ""
     )
 
     is_read = bool(item.get("isRead") if "isRead" in item else item.get("is_read") or item.get("isRead") or False)
diff --git a/tests/test_external_api.py b/tests/test_external_api.py
index cb70826..3d8010d 100644
--- a/tests/test_external_api.py
+++ b/tests/test_external_api.py
@@ -86,7 +86,9 @@ class ExternalApiBaseTest(unittest.TestCase):
         }
 
     @staticmethod
-    def _graph_detail(message_id: str = "msg-1", body_text: str = "Your code is 123456", html_text: str = "<p>Your code is 123456</p>"):
+    def _graph_detail(
+        message_id: str = "msg-1", body_text: str = "Your code is 123456", html_text: str = "<p>Your code is 123456</p>"
+    ):
         return {
             "id": message_id,
             "subject": "Your verification code",
diff --git a/tests/test_ui_settings_external_api_key.py b/tests/test_ui_settings_external_api_key.py
index 9d8b9b4..9e4ec20 100644
--- a/tests/test_ui_settings_external_api_key.py
+++ b/tests/test_ui_settings_external_api_key.py
@@ -37,4 +37,3 @@ class ExternalApiKeySettingsUITests(unittest.TestCase):
 
 if __name__ == "__main__":
     unittest.main()
-