diff --git a/app/core/database.py b/app/core/database.py
index 0472e10..c75fe1e 100644
--- a/app/core/database.py
+++ b/app/core/database.py
@@ -1,4 +1,4 @@
-from collections.abc import AsyncGenerator
+from collections.abc import AsyncGenerator, Callable
 
 from sqlalchemy.ext.asyncio import AsyncEngine, create_async_engine
 from sqlmodel import SQLModel
@@ -38,9 +38,9 @@ async def get_db() -> AsyncGenerator[AsyncSession, None]:
             await session.close()
 
 
-def get_session_factory():
+def get_session_factory() -> Callable[[], AsyncSession]:
     """Get a session factory function for services."""
-    def session_factory():
+    def session_factory() -> AsyncSession:
         return AsyncSession(engine)
     return session_factory
 
diff --git a/app/core/dependencies.py b/app/core/dependencies.py
index 292ded3..5a7e56e 100644
--- a/app/core/dependencies.py
+++ b/app/core/dependencies.py
@@ -135,8 +135,6 @@ async def get_current_user_api_token(
                 detail="Account is deactivated",
             )
 
-        return user
-
     except HTTPException:
         # Re-raise HTTPExceptions without wrapping them
         raise
@@ -146,6 +144,8 @@ async def get_current_user_api_token(
             status_code=status.HTTP_401_UNAUTHORIZED,
             detail="Could not validate API token",
         ) from e
+    else:
+        return user
 
 
 async def get_current_user_flexible(
diff --git a/app/models/credit_transaction.py b/app/models/credit_transaction.py
index e4dd2a8..dd9c92f 100644
--- a/app/models/credit_transaction.py
+++ b/app/models/credit_transaction.py
@@ -17,7 +17,8 @@ class CreditTransaction(BaseModel, table=True):
 
     user_id: int = Field(foreign_key="user.id", nullable=False)
     action_type: str = Field(nullable=False)
-    amount: int = Field(nullable=False)  # Negative for deductions, positive for additions
+    # Negative for deductions, positive for additions
+    amount: int = Field(nullable=False)
     balance_before: int = Field(nullable=False)
     balance_after: int = Field(nullable=False)
     description: str = Field(nullable=False)
diff --git a/app/models/extraction.py b/app/models/extraction.py
index 3f71b22..200f7b0 100644
--- a/app/models/extraction.py
+++ b/app/models/extraction.py
@@ -25,7 +25,8 @@ class Extraction(BaseModel, table=True):
     status: str = Field(nullable=False, default="pending")
     error: str | None = Field(default=None)
 
-    # constraints - only enforce uniqueness when both service and service_id are not null
+    # constraints - only enforce uniqueness when both service and service_id
+    # are not null
     __table_args__ = ()
 
     # relationships
diff --git a/app/schemas/__init__.py b/app/schemas/__init__.py
index bb35c3c..0c96d9d 100644
--- a/app/schemas/__init__.py
+++ b/app/schemas/__init__.py
@@ -28,25 +28,16 @@ from .playlist import (
 )
 
 __all__ = [
-    # Auth schemas
     "ApiTokenRequest",
     "ApiTokenResponse",
     "ApiTokenStatusResponse",
     "AuthResponse",
-    "TokenResponse",
-    "UserLoginRequest",
-    "UserRegisterRequest",
-    "UserResponse",
-    # Common schemas
     "HealthResponse",
     "MessageResponse",
-    "StatusResponse",
-    # Player schemas
     "PlayerModeRequest",
     "PlayerSeekRequest",
     "PlayerStateResponse",
     "PlayerVolumeRequest",
-    # Playlist schemas
     "PlaylistAddSoundRequest",
     "PlaylistCreateRequest",
     "PlaylistReorderRequest",
@@ -54,4 +45,9 @@ __all__ = [
     "PlaylistSoundResponse",
     "PlaylistStatsResponse",
     "PlaylistUpdateRequest",
+    "StatusResponse",
+    "TokenResponse",
+    "UserLoginRequest",
+    "UserRegisterRequest",
+    "UserResponse",
 ]
diff --git a/app/schemas/playlist.py b/app/schemas/playlist.py
index 7fb1064..1911d7c 100644
--- a/app/schemas/playlist.py
+++ b/app/schemas/playlist.py
@@ -40,7 +40,8 @@ class PlaylistResponse(BaseModel):
     def from_playlist(cls, playlist: Playlist) -> "PlaylistResponse":
         """Create response from playlist model."""
         if playlist.id is None:
-            raise ValueError("Playlist ID cannot be None")
+            msg = "Playlist ID cannot be None"
+            raise ValueError(msg)
         return cls(
             id=playlist.id,
             name=playlist.name,
@@ -70,7 +71,8 @@ class PlaylistSoundResponse(BaseModel):
     def from_sound(cls, sound: Sound) -> "PlaylistSoundResponse":
         """Create response from sound model."""
         if sound.id is None:
-            raise ValueError("Sound ID cannot be None")
+            msg = "Sound ID cannot be None"
+            raise ValueError(msg)
         return cls(
             id=sound.id,
             name=sound.name,