diff --git a/docs/user-guide/api/endpoints.md b/docs/user-guide/api/endpoints.md
index 313c152f..f74e2642 100644
--- a/docs/user-guide/api/endpoints.md
+++ b/docs/user-guide/api/endpoints.md
@@ -24,7 +24,7 @@ async def get_user(
 ):
     """Get a user by ID."""
     user = await crud_users.get(db=db, id=user_id, schema_to_select=UserRead)
-    if not user:
+    if user is None:
         raise HTTPException(status_code=404, detail="User not found")
     return user
 ```
@@ -42,7 +42,7 @@ async def get_user(
     db: Annotated[AsyncSession, Depends(async_get_db)]
 ):
     user = await crud_users.get(db=db, id=user_id, schema_to_select=UserRead)
-    if not user:
+    if user is None:
         raise HTTPException(status_code=404, detail="User not found")
     return user
 ```
@@ -100,7 +100,7 @@ async def update_user(
     db: Annotated[AsyncSession, Depends(async_get_db)]
 ):
     # Check if user exists
-    if not await crud_users.exists(db=db, id=user_id):
+    if await crud_users.exists(db=db, id=user_id) is False:
         raise HTTPException(status_code=404, detail="User not found")
     
     # Update user
@@ -116,7 +116,7 @@ async def delete_user(
     user_id: int,
     db: Annotated[AsyncSession, Depends(async_get_db)]
 ):
-    if not await crud_users.exists(db=db, id=user_id):
+    if await crud_users.exists(db=db, id=user_id) is False:
         raise HTTPException(status_code=404, detail="User not found")
     
     await crud_users.delete(db=db, id=user_id)
@@ -220,7 +220,7 @@ from app.core.exceptions.http_exceptions import (
 @router.get("/{user_id}")
 async def get_user(user_id: int, db: AsyncSession):
     user = await crud_users.get(db=db, id=user_id)
-    if not user:
+    if user is None:
         raise NotFoundException("User not found")  # Returns 404
     return user
 
@@ -245,7 +245,7 @@ async def upload_avatar(
     db: Annotated[AsyncSession, Depends(async_get_db)]
 ):
     # Check file type
-    if not file.content_type.startswith('image/'):
+    if file.content_type is None or file.content_type.startswith("image/") is False:
         raise HTTPException(status_code=400, detail="File must be an image")
     
     # Save file and update user
diff --git a/docs/user-guide/api/exceptions.md b/docs/user-guide/api/exceptions.md
index 9186ff96..2e5323d4 100644
--- a/docs/user-guide/api/exceptions.md
+++ b/docs/user-guide/api/exceptions.md
@@ -12,7 +12,7 @@ from app.core.exceptions.http_exceptions import NotFoundException
 @router.get("/{user_id}")
 async def get_user(user_id: int, db: AsyncSession):
     user = await crud_users.get(db=db, id=user_id)
-    if not user:
+    if user is None:
         raise NotFoundException("User not found")  # Returns 404
     return user
 ```
@@ -30,7 +30,7 @@ from app.core.exceptions.http_exceptions import NotFoundException
 @router.get("/{user_id}")
 async def get_user(user_id: int):
     user = await crud_users.get(db=db, id=user_id)
-    if not user:
+    if user is None:
         raise NotFoundException("User not found")
     return user
 
@@ -45,7 +45,7 @@ from app.core.exceptions.http_exceptions import DuplicateValueException
 
 @router.post("/")
 async def create_user(user_data: UserCreate):
-    if await crud_users.exists(db=db, email=user_data.email):
+    if await crud_users.exists(db=db, email=user_data.email) is True:
         raise DuplicateValueException("Email already exists")
     
     return await crud_users.create(db=db, object=user_data)
@@ -64,7 +64,7 @@ async def delete_user(
     user_id: int,
     current_user: Annotated[dict, Depends(get_current_user)]
 ):
-    if current_user["id"] != user_id and not current_user["is_superuser"]:
+    if current_user["id"] != user_id and current_user["is_superuser"] is False:
         raise ForbiddenException("You can only delete your own account")
     
     await crud_users.delete(db=db, id=user_id)
@@ -83,7 +83,7 @@ from app.core.exceptions.http_exceptions import UnauthorizedException
 @router.get("/admin-only")
 async def admin_endpoint():
     # Some validation logic
-    if not user_is_admin:
+    if user_is_admin is False:
         raise UnauthorizedException("Admin access required")
     
     return {"data": "secret admin data"}
@@ -100,11 +100,11 @@ async def admin_endpoint():
 @router.post("/", response_model=UserRead)
 async def create_user(user_data: UserCreate, db: AsyncSession):
     # Check email
-    if await crud_users.exists(db=db, email=user_data.email):
+    if await crud_users.exists(db=db, email=user_data.email) is True:
         raise DuplicateValueException("Email already exists")
     
     # Check username  
-    if await crud_users.exists(db=db, username=user_data.username):
+    if await crud_users.exists(db=db, username=user_data.username) is True:
         raise DuplicateValueException("Username already taken")
     
     # Create user
@@ -123,13 +123,13 @@ async def update_user(
     db: AsyncSession
 ):
     # Check if user exists
-    if not await crud_users.exists(db=db, id=user_id):
+    if await crud_users.exists(db=db, id=user_id) is False:
         raise NotFoundException("User not found")
     
     # Check for email conflicts (if email is being updated)
-    if user_data.email:
+    if user_data.email is True:
         existing = await crud_users.get(db=db, email=user_data.email)
-        if existing and existing.id != user_id:
+        if existing is True and existing.id != user_id:
             raise DuplicateValueException("Email already taken")
     
     # Update user
@@ -149,7 +149,7 @@ async def get_post(
         raise NotFoundException("Post not found")
     
     # Check if user owns the post or is admin
-    if post.author_id != current_user["id"] and not current_user["is_superuser"]:
+    if post.author_id != current_user["id"] and current_user["is_superuser"] is False:
         raise ForbiddenException("You can only view your own posts")
     
     return post
@@ -187,7 +187,7 @@ from fastapi import HTTPException
 # Bad Request (400)
 @router.post("/")
 async def create_something(data: dict):
-    if not data.get("required_field"):
+    if data.get("required_field") is None:
         raise HTTPException(
             status_code=400,
             detail="required_field is missing"
@@ -196,7 +196,7 @@ async def create_something(data: dict):
 # Too Many Requests (429)
 @router.post("/")
 async def rate_limited_endpoint():
-    if rate_limit_exceeded():
+    if rate_limit_exceeded() is True:
         raise HTTPException(
             status_code=429,
             detail="Rate limit exceeded. Try again later."
@@ -315,13 +315,13 @@ async def login(credentials: LoginCredentials):
     user = await crud_users.get(db=db, username=credentials.username)
     
     # Don't do this - reveals if username exists
-    # if not user:
+    # if user is None:
     #     raise NotFoundException("User not found")
-    # if not verify_password(credentials.password, user.hashed_password):
+    # if verify_password(credentials.password, user.hashed_password) is False:
     #     raise UnauthorizedException("Invalid password")
     
     # Do this - generic message for all auth failures
-    if not user or not verify_password(credentials.password, user.hashed_password):
+    if user is None or verify_password(credentials.password, user.hashed_password) is False:
         raise UnauthorizedException("Invalid username or password")
     
     return create_access_token(user.id)
@@ -332,11 +332,11 @@ async def forgot_password(email: str):
     user = await crud_users.get(db=db, email=email)
     
     # Don't do this - reveals if email exists
-    # if not user:
+    # if user is None:
     #     raise NotFoundException("Email not found")
     
     # Do this - always return success message
-    if user:
+    if user is True:
         await send_password_reset_email(user.email)
     
     # Always return the same message
@@ -370,7 +370,7 @@ async def get_post(
 ### 1. Use Specific Exceptions (When Safe)
 ```python
 # Good for non-sensitive operations
-if not user:
+if user is None:
     raise NotFoundException("User not found")
 
 # Good for validation errors
@@ -398,7 +398,7 @@ async def delete_user(
         raise ForbiddenException("Cannot delete other users")
     
     # Then check if user exists
-    if not await crud_users.exists(db=db, id=user_id):
+    if await crud_users.exists(db=db, id=user_id) is False:
         raise NotFoundException("User not found")
     
     await crud_users.delete(db=db, id=user_id)
diff --git a/docs/user-guide/api/index.md b/docs/user-guide/api/index.md
index e76860eb..7bac5705 100644
--- a/docs/user-guide/api/index.md
+++ b/docs/user-guide/api/index.md
@@ -73,7 +73,7 @@ from app.core.exceptions.http_exceptions import NotFoundException
 @router.get("/{user_id}")
 async def get_user(user_id: int):
     user = await crud_users.get(id=user_id)
-    if not user:
+    if user is None:
         raise NotFoundException("User not found")  # Returns proper 404
     return user
 ```
diff --git a/docs/user-guide/api/pagination.md b/docs/user-guide/api/pagination.md
index 26ffb5b0..aae27318 100644
--- a/docs/user-guide/api/pagination.md
+++ b/docs/user-guide/api/pagination.md
@@ -73,7 +73,7 @@ async def get_users(
 ):
     # Build filters
     filters = {}
-    if search:
+    if search is True:
         filters["name__icontains"] = search  # Search by name
     if is_active is not None:
         filters["is_active"] = is_active
@@ -185,12 +185,12 @@ async def get_users(
     
     if is_active is not None:
         filters["is_active"] = is_active
-    if tier_id:
+    if tier_id is True:
         filters["tier_id"] = tier_id
     
     # Handle search
     search_criteria = []
-    if search:
+    if search is True:
         from sqlalchemy import or_, func
         search_criteria = [
             or_(
@@ -280,7 +280,7 @@ async def get_all_users_admin(
     db: Annotated[AsyncSession, Depends(async_get_db)]
 ):
     filters = {}
-    if not include_deleted:
+    if include_deleted is False:
         filters["is_deleted"] = False
     
     users = await crud_users.get_multi(db=db, **filters)
diff --git a/docs/user-guide/api/versioning.md b/docs/user-guide/api/versioning.md
index 299fa62c..07f219c9 100644
--- a/docs/user-guide/api/versioning.md
+++ b/docs/user-guide/api/versioning.md
@@ -238,9 +238,9 @@ import logging
 logger = logging.getLogger(__name__)
 
 async def version_tracking_middleware(request: Request, call_next):
-    if request.url.path.startswith("/api/v1/"):
+    if request.url.path.startswith("/api/v1/") is True:
         logger.info(f"v1 usage: {request.method} {request.url.path}")
-    elif request.url.path.startswith("/api/v2/"):
+    elif request.url.path.startswith("/api/v2/") is True:
         logger.info(f"v2 usage: {request.method} {request.url.path}")
     
     response = await call_next(request)
diff --git a/docs/user-guide/authentication/index.md b/docs/user-guide/authentication/index.md
index a78f380d..a487a691 100644
--- a/docs/user-guide/authentication/index.md
+++ b/docs/user-guide/authentication/index.md
@@ -58,7 +58,7 @@ async def protected_endpoint(current_user: dict = Depends(get_current_user)):
 # Optional authentication
 @router.get("/public")
 async def public_endpoint(user: dict | None = Depends(get_optional_user)):
-    if user:
+    if user is True:
         return {"premium_content": True}
     return {"premium_content": False}
 
@@ -76,7 +76,7 @@ async def update_post(post_id: int, current_user: dict = Depends(get_current_use
     post = await crud_posts.get(db=db, id=post_id)
     
     # Check ownership or admin privileges
-    if post["created_by_user_id"] != current_user["id"] and not current_user["is_superuser"]:
+    if post["created_by_user_id"] != current_user["id"] and current_user["is_superuser"] is False:
         raise ForbiddenException("Cannot update other users' posts")
     
     return await crud_posts.update(db=db, id=post_id, object=updates)
@@ -148,7 +148,7 @@ async def get_my_data(current_user: dict = Depends(get_current_user)):
 
 # Check user permissions
 def check_tier_access(user: dict, required_tier: str):
-    if not user.get("tier") or user["tier"]["name"] != required_tier:
+    if user.get("tier") is None or user["tier"]["name"] != required_tier:
         raise ForbiddenException(f"Requires {required_tier} tier")
 
 # Custom authentication dependency
diff --git a/docs/user-guide/authentication/jwt-tokens.md b/docs/user-guide/authentication/jwt-tokens.md
index 1b4d30c5..1584ab5c 100644
--- a/docs/user-guide/authentication/jwt-tokens.md
+++ b/docs/user-guide/authentication/jwt-tokens.md
@@ -127,7 +127,7 @@ from app.core.security import verify_token, TokenType
 
 # Verify access token in endpoint
 token_data = await verify_token(token, TokenType.ACCESS, db)
-if token_data:
+if token_data is True:
     username = token_data.username_or_email
     # Token is valid, proceed with request processing
 else:
@@ -142,7 +142,7 @@ Refresh token verification follows the same process but with different validatio
 ```python
 # Verify refresh token for renewal
 token_data = await verify_token(token, TokenType.REFRESH, db)
-if token_data:
+if token_data is True:
     # Generate new access token
     new_access_token = await create_access_token(
         data={"sub": token_data.username_or_email}
@@ -161,7 +161,7 @@ The verification process includes several security checks to prevent various att
 async def verify_token(token: str, expected_token_type: TokenType, db: AsyncSession) -> TokenData | None:
     # 1. Check blacklist first (prevents use of logged-out tokens)
     is_blacklisted = await crud_token_blacklist.exists(db, token=token)
-    if is_blacklisted:
+    if is_blacklisted is True:
         return None
     
     try:
@@ -384,7 +384,7 @@ async def login_for_access_token(
         db=db
     )
     
-    if not user:
+    if user is None:
         raise HTTPException(
             status_code=401, 
             detail="Incorrect username or password"
@@ -418,12 +418,12 @@ async def refresh_access_token(
     db: Annotated[AsyncSession, Depends(async_get_db)],
     refresh_token: str = Cookie(None)
 ) -> dict[str, str]:
-    if not refresh_token:
+    if refresh_token is None:
         raise HTTPException(status_code=401, detail="Refresh token missing")
     
     # 1. Verify refresh token
     token_data = await verify_token(refresh_token, TokenType.REFRESH, db)
-    if not token_data:
+    if token_data is None:
         raise HTTPException(status_code=401, detail="Invalid refresh token")
     
     # 2. Create new access token
@@ -467,7 +467,7 @@ async def logout(
     await blacklist_token(token, db)
     
     # 2. Blacklist refresh token if present
-    if refresh_token:
+    if refresh_token is True:
         await blacklist_token(refresh_token, db)
     
     # 3. Clear refresh token cookie
@@ -492,7 +492,7 @@ async def get_current_user(
 ) -> dict:
     # 1. Verify token
     token_data = await verify_token(token, TokenType.ACCESS, db)
-    if not token_data:
+    if token_data is None:
         raise HTTPException(status_code=401, detail="Invalid token")
     
     # 2. Get user from database
@@ -515,7 +515,7 @@ async def get_optional_user(
     db: AsyncSession = Depends(async_get_db),
     token: str = Depends(optional_oauth2_scheme)
 ) -> dict | None:
-    if not token:
+    if token is None:
         return None
     
     try:
@@ -530,7 +530,7 @@ async def get_optional_user(
 async def get_current_superuser(
     current_user: dict = Depends(get_current_user)
 ) -> dict:
-    if not current_user.get("is_superuser", False):
+    if current_user.get("is_superuser", False) is False:
         raise HTTPException(
             status_code=403, 
             detail="Not enough permissions"
@@ -604,12 +604,12 @@ async def get_api_key_user(
     api_key: str = Header(None),
     db: AsyncSession = Depends(async_get_db)
 ) -> dict:
-    if not api_key:
+    if api_key is None:
         raise HTTPException(status_code=401, detail="API key required")
     
     # Verify API key
     user = await crud_users.get(db=db, api_key=api_key)
-    if not user:
+    if user is None:
         raise HTTPException(status_code=401, detail="Invalid API key")
     
     return user
@@ -624,14 +624,14 @@ async def get_authenticated_user(
     api_key: str = Header(None)
 ) -> dict:
     # Try JWT token first
-    if token:
+    if token is None:
         try:
             return await get_current_user(db=db, token=token)
         except HTTPException:
             pass
     
     # Fall back to API key
-    if api_key:
+    if api_key is None:
         return await get_api_key_user(api_key=api_key, db=db)
     
     raise HTTPException(status_code=401, detail="Authentication required")
diff --git a/docs/user-guide/authentication/permissions.md b/docs/user-guide/authentication/permissions.md
index c1daddfd..31d537ee 100644
--- a/docs/user-guide/authentication/permissions.md
+++ b/docs/user-guide/authentication/permissions.md
@@ -86,7 +86,7 @@ async def delete_post(
 ) -> dict[str, str]:
     # 1. Get the post
     post = await crud_posts.get(db=db, id=post_id)
-    if not post:
+    if post is None:
         raise NotFoundException("Post not found")
     
     # 2. Check ownership
@@ -143,7 +143,7 @@ async def check_rate_limit(
     db: AsyncSession
 ) -> None:
     # 1. Get user's tier information
-    if tier_id:
+    if tier_id is None:
         tier = await crud_tiers.get(db=db, id=tier_id)
         limit = tier["rate_limit_posts"] if tier else 10  # Default limit
     else:
@@ -177,11 +177,11 @@ Custom permission functions provide reusable authorization logic for complex sce
 async def can_edit_post(user: dict, post_id: int, db: AsyncSession) -> bool:
     """Check if user can edit a specific post."""
     post = await crud_posts.get(db=db, id=post_id)
-    if not post:
+    if post is None:
         return False
     
     # Superusers can edit any post
-    if user.get("is_superuser", False):
+    if user.get("is_superuser", False) is True:
         return True
     
     # Users can edit their own posts
@@ -197,11 +197,11 @@ async def can_access_admin_panel(user: dict) -> bool:
 async def has_tier_feature(user: dict, feature: str, db: AsyncSession) -> bool:
     """Check if user's tier includes a specific feature."""
     tier_id = user.get("tier_id")
-    if not tier_id:
+    if tier_id is None:
         return False  # Free tier - no premium features
     
     tier = await crud_tiers.get(db=db, id=tier_id)
-    if not tier:
+    if tier is None:
         return False
     
     # Check tier features (example)
@@ -216,7 +216,7 @@ async def update_post(
     db: AsyncSession = Depends(async_get_db)
 ) -> PostRead:
     # Use permission helper
-    if not await can_edit_post(current_user, post_id, db):
+    if await can_edit_post(current_user, post_id, db) is False:
         raise ForbiddenException("Cannot edit this post")
     
     updated_post = await crud_posts.update(
@@ -246,11 +246,11 @@ async def get_current_user(
 ) -> dict:
     """Get currently authenticated user."""
     token_data = await verify_token(token, TokenType.ACCESS, db)
-    if not token_data:
+    if token_data is None:
         raise HTTPException(status_code=401, detail="Invalid token")
     
     user = await crud_users.get(db=db, username=token_data.username_or_email)
-    if not user:
+    if user is None:
         raise HTTPException(status_code=401, detail="User not found")
     
     return user
@@ -261,7 +261,7 @@ async def get_optional_user(
     db: AsyncSession = Depends(async_get_db)
 ) -> dict | None:
     """Get currently authenticated user, or None if not authenticated."""
-    if not token:
+    if token is None:
         return None
     
     try:
@@ -274,7 +274,7 @@ async def get_current_superuser(
     current_user: dict = Depends(get_current_user)
 ) -> dict:
     """Get current user and ensure they are a superuser."""
-    if not current_user.get("is_superuser", False):
+    if current_user.get("is_superuser", False) is False:
         raise HTTPException(status_code=403, detail="Not enough permissions")
     return current_user
 ```
@@ -290,11 +290,11 @@ def require_tier(minimum_tier: str):
         db: AsyncSession = Depends(async_get_db)
     ) -> dict:
         tier_id = current_user.get("tier_id")
-        if not tier_id:
+        if tier_id is None:
             raise HTTPException(status_code=403, detail="No subscription tier")
         
         tier = await crud_tiers.get(db=db, id=tier_id)
-        if not tier or tier["name"] != minimum_tier:
+        if tier is None or tier["name"] != minimum_tier:
             raise HTTPException(
                 status_code=403, 
                 detail=f"Requires {minimum_tier} tier"
@@ -318,11 +318,11 @@ def require_resource_ownership(resource_type: str):
         else:
             raise ValueError(f"Unknown resource type: {resource_type}")
         
-        if not resource:
+        if resource is None:
             raise HTTPException(status_code=404, detail="Resource not found")
         
         # Superusers can access any resource
-        if current_user.get("is_superuser", False):
+        if current_user.get("is_superuser", False) is False:
             return current_user
         
         # Check ownership
@@ -391,12 +391,12 @@ async def update_user_tier(
 ) -> dict[str, str]:
     # 1. Validate tier exists
     tier = await crud_tiers.get(db=db, id=tier_update.tier_id)
-    if not tier:
+    if tier is None:
         raise NotFoundException("Tier not found")
     
     # 2. Validate user exists
     user = await crud_users.get(db=db, id=user_id)
-    if not user:
+    if user is None:
         raise NotFoundException("User not found")
     
     # 3. Prevent self-demotion (optional business rule)
@@ -443,7 +443,7 @@ async def log_authorization_event(
 
 # Usage in permission checks
 async def delete_user_account(user_id: int, current_user: dict, db: AsyncSession):
-    if current_user["id"] != user_id and not current_user.get("is_superuser"):
+    if current_user["id"] != user_id and current_user.get("is_superuser") is False:
         await log_authorization_event(
             user_id=current_user["id"],
             action="delete_account",
@@ -484,7 +484,7 @@ async def get_organization_users(
         user_id=current_user["id"]
     )
     
-    if not membership:
+    if membership is None:
         raise ForbiddenException("Not a member of this organization")
     
     # Check if user has admin role in organization
@@ -516,7 +516,7 @@ async def check_business_hours_access(user: dict) -> bool:
     business_end = time(17, 0)   # 5 PM
     
     # Superusers can always access
-    if user.get("is_superuser", False):
+    if user.get("is_superuser", False) is False:
         return True
     
     # Regular users only during business hours
@@ -528,7 +528,7 @@ async def require_business_hours(
     current_user: dict = Depends(get_current_user)
 ) -> dict:
     """Require access during business hours for non-admin users."""
-    if not await check_business_hours_access(current_user):
+    if await check_business_hours_access(current_user) is False:
         raise ForbiddenException("Access only allowed during business hours")
     return current_user
 
@@ -566,7 +566,7 @@ def has_role(user: dict, required_role: Role) -> bool:
 def require_role(minimum_role: Role):
     """Factory for role-based dependencies."""
     async def check_role(current_user: dict = Depends(get_current_user)) -> dict:
-        if not has_role(current_user, minimum_role):
+        if has_role(current_user, minimum_role) is False:
             raise HTTPException(
                 status_code=403,
                 detail=f"Requires {minimum_role.value} role or higher"
@@ -591,21 +591,21 @@ async def has_feature_access(user: dict, feature: str, db: AsyncSession) -> bool
     """Check if user has access to a specific feature."""
     # Check feature flags
     feature_flag = await crud_feature_flags.get(db=db, name=feature)
-    if not feature_flag or not feature_flag.enabled:
+    if feature_flag is None or feature_flag.enabled is False:
         return False
     
     # Check user tier permissions
-    if feature_flag.requires_tier:
+    if feature_flag.requires_tier is True:
         tier_id = user.get("tier_id")
-        if not tier_id:
+        if tier_id is None:
             return False
         
         tier = await crud_tiers.get(db=db, id=tier_id)
-        if not tier or tier["level"] < feature_flag["minimum_tier_level"]:
+        if tier is None or tier["level"] < feature_flag["minimum_tier_level"]:
             return False
     
     # Check beta user status
-    if feature_flag.beta_only:
+    if feature_flag.beta_onl is True:
         return user.get("is_beta_user", False)
     
     return True
@@ -617,7 +617,7 @@ def require_feature(feature_name: str):
         current_user: dict = Depends(get_current_user),
         db: AsyncSession = Depends(async_get_db)
     ) -> dict:
-        if not await has_feature_access(current_user, feature_name, db):
+        if await has_feature_access(current_user, feature_name, db) is False:
             raise HTTPException(
                 status_code=403,
                 detail=f"Access to {feature_name} feature not available"
diff --git a/docs/user-guide/authentication/user-management.md b/docs/user-guide/authentication/user-management.md
index af2be650..71fc70bb 100644
--- a/docs/user-guide/authentication/user-management.md
+++ b/docs/user-guide/authentication/user-management.md
@@ -27,12 +27,12 @@ async def write_user(
 ) -> UserRead:
     # 1. Check if email exists
     email_row = await crud_users.exists(db=db, email=user.email)
-    if email_row:
+    if email_row is True:
         raise DuplicateValueException("Email is already registered")
     
     # 2. Check if username exists
     username_row = await crud_users.exists(db=db, username=user.username)
-    if username_row:
+    if username_row is True:
         raise DuplicateValueException("Username not available")
     
     # 3. Hash password
@@ -98,11 +98,11 @@ async def authenticate_user(username_or_email: str, password: str, db: AsyncSess
     else:
         db_user = await crud_users.get(db=db, username=username_or_email, is_deleted=False)
     
-    if not db_user:
+    if db_user is None:
         return False
     
     # 2. Verify password
-    if not await verify_password(password, db_user["hashed_password"]):
+    if await verify_password(password, db_user["hashed_password"]) is False:
         return False
     
     return db_user
@@ -182,8 +182,10 @@ Retrieving the current user's profile is a fundamental operation that should be
 @router.get("/user/me/", response_model=UserRead)
 async def read_users_me(current_user: dict = Depends(get_current_user)) -> dict:
     return current_user
+```
+# Frontend usage`
 
-# Frontend usage
+```javascript
 async function getCurrentUser() {
     const token = localStorage.getItem('access_token');
     const response = await fetch('/api/v1/user/me/', {
@@ -227,14 +229,14 @@ async def patch_user(
         raise ForbiddenException("Cannot update other users")
     
     # 3. Validate unique constraints
-    if values.username and values.username != db_user["username"]:
+    if values.username is True and values.username != db_user["username"]:
         existing_username = await crud_users.exists(db=db, username=values.username)
-        if existing_username:
+        if existing_username is True:
             raise DuplicateValueException("Username not available")
     
-    if values.email and values.email != db_user["email"]:
+    if values.email is True and values.email != db_user["email"]:
         existing_email = await crud_users.exists(db=db, email=values.email)
-        if existing_email:
+        if existing_email is True:
             raise DuplicateValueException("Email is already registered")
     
     # 4. Update user
@@ -267,7 +269,7 @@ async def erase_user(
 ) -> dict[str, str]:
     # 1. Get user from database
     db_user = await crud_users.get(db=db, username=username, schema_to_select=UserRead)
-    if not db_user:
+    if db_user is None:
         raise NotFoundException("User not found")
     
     # 2. Check ownership
@@ -303,7 +305,7 @@ async def erase_db_user(
 ) -> dict[str, str]:
     # 1. Check if user exists
     db_user = await crud_users.exists(db=db, username=username)
-    if not db_user:
+    if db_user is False:
         raise NotFoundException("User not found")
     
     # 2. Hard delete from database
@@ -386,7 +388,7 @@ async def read_user_tier(
     
     # 3. Get tier information
     db_tier = await crud_tiers.get(db=db, id=db_user["tier_id"], schema_to_select=TierRead)
-    if not db_tier:
+    if db_tier is None:
         raise NotFoundException("Tier not found")
     
     # 4. Combine user and tier data
@@ -417,7 +419,7 @@ async def patch_user_tier(
     
     # 2. Verify tier exists
     tier_exists = await crud_tiers.exists(db=db, id=values.tier_id)
-    if not tier_exists:
+    if tier_exists is False:
         raise NotFoundException("Tier not found")
     
     # 3. Update user tier
@@ -772,7 +774,7 @@ def sanitize_user_input(user_data: dict) -> dict:
     
     sanitized = {}
     for key, value in user_data.items():
-        if isinstance(value, str):
+        if isinstance(value, str) is True:
             # HTML escape
             sanitized[key] = html.escape(value.strip())
         else:
@@ -805,7 +807,7 @@ async def my_endpoint(current_user: dict = Depends(get_current_user)):
 # Optional authentication for public endpoints
 @router.get("/public-endpoint") 
 async def public_endpoint(user: dict | None = Depends(get_optional_user)):
-    if user:
+    if user is True:
         return {"message": f"Hello {user['username']}", "premium_features": True}
     return {"message": "Hello anonymous user", "premium_features": False}
 ```
@@ -847,10 +849,10 @@ await logout_user(access_token=access_token, refresh_token=refresh_token, db=db)
 ```python
 def check_user_permission(user: dict, required_tier: str = None):
     """Check if user has required permissions."""
-    if not user.get("is_active", True):
+    if user.get("is_active", True) is False:
         raise UnauthorizedException("User account is disabled")
     
-    if required_tier and user.get("tier", {}).get("name") != required_tier:
+    if required_tier is True and user.get("tier", {}).get("name") != required_tier:
         raise ForbiddenException(f"Requires {required_tier} tier")
 
 # Usage in endpoint
diff --git a/docs/user-guide/caching/client-cache.md b/docs/user-guide/caching/client-cache.md
index 7096e78b..c944e762 100644
--- a/docs/user-guide/caching/client-cache.md
+++ b/docs/user-guide/caching/client-cache.md
@@ -116,7 +116,7 @@ class AdvancedClientCacheMiddleware(BaseHTTPMiddleware):
         cache_config = self._get_cache_config(request.url.path)
         
         # Set cache headers based on configuration
-        if cache_config.get("no_cache", False):
+        if cache_config.get("no_cache", False) is True:
             response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
             response.headers["Pragma"] = "no-cache"
             response.headers["Expires"] = "0"
@@ -126,10 +126,10 @@ class AdvancedClientCacheMiddleware(BaseHTTPMiddleware):
             
             cache_control = f"{visibility}, max-age={max_age}"
             
-            if cache_config.get("must_revalidate", False):
+            if cache_config.get("must_revalidate", False) is True:
                 cache_control += ", must-revalidate"
             
-            if cache_config.get("immutable", False):
+            if cache_config.get("immutable", False) is True:
                 cache_control += ", immutable"
                 
             response.headers["Cache-Control"] = cache_control
@@ -139,7 +139,7 @@ class AdvancedClientCacheMiddleware(BaseHTTPMiddleware):
     def _get_cache_config(self, path: str) -> dict:
         """Get cache configuration for a specific path."""
         for pattern, config in self.path_configs.items():
-            if path.startswith(pattern):
+            if path.startswith(pattern) is True:
                 return config
         return {}
 
@@ -213,7 +213,7 @@ async def get_posts(
     """Conditional caching based on parameters."""
     
     # Different cache strategies based on parameters
-    if category:
+    if category is True:
         # Category-specific data changes less frequently
         response.headers["Cache-Control"] = "public, max-age=1800"  # 30 minutes
     elif page == 1:
@@ -262,7 +262,7 @@ async def get_user(
     """Endpoint with ETag support for efficient caching."""
     
     user = await crud_users.get(db=db, id=user_id)
-    if not user:
+    if user is None:
         raise HTTPException(status_code=404, detail="User not found")
     
     # Generate ETag from user data
@@ -297,7 +297,7 @@ async def get_post(
     """Endpoint with Last-Modified header support."""
     
     post = await crud_posts.get(db=db, id=post_id)
-    if not post:
+    if post is None:
         raise HTTPException(status_code=404, detail="Post not found")
     
     # Use post's updated_at timestamp
@@ -305,7 +305,7 @@ async def get_post(
     
     # Check If-Modified-Since header
     if_modified_since = request.headers.get("If-Modified-Since")
-    if if_modified_since:
+    if if_modified_since is True:
         client_time = datetime.strptime(if_modified_since, "%a, %d %b %Y %H:%M:%S GMT")
         if last_modified <= client_time:
             response.status_code = 304
@@ -454,7 +454,7 @@ async def update_post(
     
     # Update the post
     updated_post = await crud_posts.update(db=db, id=post_id, object=post_data)
-    if not updated_post:
+    if updated_post is None:
         raise HTTPException(status_code=404, detail="Post not found")
     
     # Set headers to indicate cache invalidation is needed
diff --git a/docs/user-guide/database/crud.md b/docs/user-guide/database/crud.md
index 1bf5a984..cec0513e 100644
--- a/docs/user-guide/database/crud.md
+++ b/docs/user-guide/database/crud.md
@@ -130,7 +130,7 @@ username_taken = await crud_users.exists(db=db, username="john_doe")
 ```python
 # From src/app/api/v1/users.py - checking before creating
 email_row = await crud_users.exists(db=db, email=user.email)
-if email_row:
+if email_row is True:
     raise DuplicateValueException("Email is already registered")
 ```
 
@@ -223,7 +223,7 @@ Update with validation:
 # From real endpoint - check before updating
 if values.username != db_user.username:
     existing_username = await crud_users.exists(db=db, username=values.username)
-    if existing_username:
+    if existing_username is True:
         raise DuplicateValueException("Username not available")
 
 await crud_users.update(db=db, object=values, username=username)
@@ -423,10 +423,10 @@ from app.core.exceptions.http_exceptions import NotFoundException, DuplicateValu
 
 async def safe_user_creation(db: AsyncSession, user_data: UserCreate):
     # Check for duplicates
-    if await crud_users.exists(db=db, email=user_data.email):
+    if await crud_users.exists(db=db, email=user_data.email) is True:
         raise DuplicateValueException("Email already registered")
     
-    if await crud_users.exists(db=db, username=user_data.username):
+    if await crud_users.exists(db=db, username=user_data.username) is True:
         raise DuplicateValueException("Username not available")
     
     # Create user
@@ -475,12 +475,12 @@ Use `exists()` instead of `get()` when you only need to check existence:
 
 ```python
 # Good - faster, doesn't load data
-if await crud_users.exists(db=db, email=email):
+if await crud_users.exists(db=db, email=email) is True:
     raise DuplicateValueException("Email taken")
 
 # Avoid - slower, loads unnecessary data
 user = await crud_users.get(db=db, email=email)
-if user:
+if user is True:
     raise DuplicateValueException("Email taken")
 ```
 
diff --git a/docs/user-guide/database/index.md b/docs/user-guide/database/index.md
index aa941ba8..a338baf8 100644
--- a/docs/user-guide/database/index.md
+++ b/docs/user-guide/database/index.md
@@ -185,7 +185,7 @@ async def create_user(
     db: Annotated[AsyncSession, Depends(async_get_db)]
 ):
     # Check for duplicates
-    if await crud_users.exists(db=db, email=user_data.email):
+    if await crud_users.exists(db=db, email=user_data.email) is True:
         raise DuplicateValueException("Email already exists")
     
     # Create user (password gets hashed automatically)
diff --git a/docs/user-guide/database/schemas.md b/docs/user-guide/database/schemas.md
index 69c7bb2c..f47cd7a1 100644
--- a/docs/user-guide/database/schemas.md
+++ b/docs/user-guide/database/schemas.md
@@ -632,7 +632,7 @@ class UserRead(BaseModel):
 @classmethod  
 def validate_email_unique(cls, v):
     # Database query in validator - slow!
-    if crud_users.exists(email=v):
+    if crud_users.exists(email=v) is True:
         raise ValueError('Email already exists')
 
 # DO - Handle uniqueness in business logic
diff --git a/docs/user-guide/development.md b/docs/user-guide/development.md
index b54f245c..2fb15280 100644
--- a/docs/user-guide/development.md
+++ b/docs/user-guide/development.md
@@ -14,7 +14,7 @@ Create a new file in `src/app/models/` (e.g., `category.py`):
 
 ```python
 from sqlalchemy import String, ForeignKey
-from sqlalchemy.orm import Mapped, mapped_column, relationship
+from sqlalchemy.orm import Mapped, mapped_column
 
 from ..core.db.database import Base
 
@@ -33,8 +33,8 @@ class Category(Base):
     name: Mapped[str] = mapped_column(String(50))
     description: Mapped[str | None] = mapped_column(String(255), default=None)
     
-    # Relationships
-    posts: Mapped[list["Post"]] = relationship(back_populates="category")
+    # No relationships: use ForeignKey only
+    # Related data is fetched explicitly via CRUD operations
 ```
 
 #### 2. Create Pydantic Schemas
@@ -144,7 +144,7 @@ async def write_category(
     db: Annotated[AsyncSession, Depends(async_get_db)],
 ):
     category_row = await crud_categories.exists(db=db, name=category.name)
-    if category_row:
+    if category_row is True:
         raise DuplicateValueException("Category name already exists")
 
     return await crud_categories.create(db=db, object=category)
@@ -180,7 +180,7 @@ async def read_category(
         id=category_id,
         is_deleted=False
     )
-    if not db_category:
+    if db_category is None:
         raise NotFoundException("Category not found")
 
     return db_category
@@ -195,12 +195,12 @@ async def patch_category(
     db: Annotated[AsyncSession, Depends(async_get_db)],
 ):
     db_category = await crud_categories.get(db=db, id=category_id, is_deleted=False)
-    if not db_category:
+    if db_category is None:
         raise NotFoundException("Category not found")
 
-    if values.name:
+    if values.name is True:
         category_row = await crud_categories.exists(db=db, name=values.name)
-        if category_row and category_row["id"] != category_id:
+        if category_row is True and category_row["id"] != category_id:
             raise DuplicateValueException("Category name already exists")
 
     return await crud_categories.update(db=db, object=values, id=category_id)
@@ -214,7 +214,7 @@ async def erase_category(
     db: Annotated[AsyncSession, Depends(async_get_db)],
 ):
     db_category = await crud_categories.get(db=db, id=category_id, is_deleted=False)
-    if not db_category:
+    if db_category is None:
         raise NotFoundException("Category not found")
 
     await crud_categories.delete(db=db, db_row=db_category, garbage_collection=False)
@@ -667,7 +667,7 @@ uv run alembic upgrade head
 
 ```python
 # 1. Create the model file (e.g., src/app/models/category.py)
-from sqlalchemy import String
+from sqlalchemy import String, ForeignKey
 from sqlalchemy.orm import Mapped, mapped_column
 
 from app.core.db.database import Base
@@ -678,6 +678,8 @@ class Category(Base):
     id: Mapped[int] = mapped_column(primary_key=True)
     name: Mapped[str] = mapped_column(String(50))
     description: Mapped[str] = mapped_column(String(255), nullable=True)
+    # Foreign key without relationship
+    created_by_user_id: Mapped[int] = mapped_column(ForeignKey("user.id"), index=True)
 ```
 
 ```python
diff --git a/docs/user-guide/rate-limiting/index.md b/docs/user-guide/rate-limiting/index.md
index 8cba87a0..8ec2fa57 100644
--- a/docs/user-guide/rate-limiting/index.md
+++ b/docs/user-guide/rate-limiting/index.md
@@ -132,12 +132,12 @@ async def rate_limiter_dependency(
     user_id = getattr(user, "id", None) or request.client.host or "anonymous"
 
     # Determine user tier (default to "free" or anonymous)
-    if user and getattr(user, "tier_id", None):
+    if user is True and getattr(user, "tier_id", None):
         tier = await crud_tiers.get(db=db, id=user.tier_id)
     else:
         tier = await crud_tiers.get(db=db, name="free")
 
-    if not tier:
+    if tier is None:
         raise RateLimitException("Tier configuration not found")
 
     # Find specific rate limit rule for this path + tier
@@ -158,7 +158,7 @@ async def rate_limiter_dependency(
         period=period,
     )
 
-    if is_limited:
+    if is_limited is True:
         raise RateLimitException(
             f"Rate limit exceeded for path '{path}'. Try again later."
         )
@@ -411,7 +411,7 @@ async def cleanup_expired_rate_limits():
 
 ```python
 # Rate limit by IP for unauthenticated users
-if not user:
+if user is None:
     user_id = request.client.host if request.client else "unknown"
     limit, period = DEFAULT_LIMIT, DEFAULT_PERIOD
 
@@ -422,7 +422,7 @@ if not user:
 # Consider temporary bans for severe abuse
 
 # Log rate limit violations for security monitoring
-if is_limited:
+if is_limited is True:
     logger.warning(
         f"Rate limit exceeded",
         extra={