diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6364ce7..c3d3e6d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -63,7 +63,7 @@ jobs:
         python -m pip install -e .[dev]
     - name: Code Format Check with Black
       run: |
-        black --check --verbose .
+        black --check --verbose ./src
 
   build:
     name: Build artifacts
diff --git a/pyproject.toml b/pyproject.toml
index a33c7dd..b6f5e96 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,16 +53,13 @@ version = {attr = "pycanape.__version__"}
   "py.typed",
 ]
 
-[tool.black]
-include = '^/((docs|src)/.*|setup)\.pyi?$'
-
 [tool.mypy]
 show_error_codes = true
 ignore_missing_imports = false
 disallow_untyped_defs = false
-disallow_incomplete_defs = false
+disallow_incomplete_defs = true
 check_untyped_defs = true
-warn_unused_ignores = false
+warn_unused_ignores = true
 warn_redundant_casts = true
 disallow_any_generics = true
 disallow_subclassing_any = true
@@ -90,13 +87,16 @@ select = [
     "ISC",  # flake8-implicit-str-concat
     "PIE",  # flake8-pie
     "RSE",  # flake8-raise
+    "RUF",  # Ruff-specific rules
     "S",  # flake8-bandit
     "SIM",  # flake8-simplify
+    "TCH",  # flake8-type-checking
     "UP",  # pyupgrade
     "W",  # pycodestyle
 ]
 ignore = [
     "E501",  # line too long
+    "RUF012",  # mutable-class-default
 ]
 
 [tool.ruff.isort]
diff --git a/src/pycanape/calibration_object.py b/src/pycanape/calibration_object.py
index c264740..a82893e 100644
--- a/src/pycanape/calibration_object.py
+++ b/src/pycanape/calibration_object.py
@@ -149,9 +149,9 @@ def __str__(self) -> str:
     def __repr__(self) -> str:
         return (
             f"{self.__class__.__name__}("
-            f"asap3_handle={repr(self._asap3_handle)}, "
-            f"module_handle={repr(self._module_handle)}, "
-            f"name={repr(self._name)}, "
+            f"asap3_handle={self._asap3_handle!r}, "
+            f"module_handle={self._module_handle!r}, "
+            f"name={self._name!r}, "
             f"object_info)"
         )
 
diff --git a/src/pycanape/cnp_api/cnp_class.py b/src/pycanape/cnp_api/cnp_class.py
index 44035aa..cdf4496 100644
--- a/src/pycanape/cnp_api/cnp_class.py
+++ b/src/pycanape/cnp_api/cnp_class.py
@@ -4,6 +4,7 @@
 
 import ctypes
 from ctypes import wintypes
+from typing import ClassVar
 
 from . import cnp_constants
 
@@ -39,7 +40,7 @@ class TTaskInfo(ctypes.Structure):
     """
 
     _pack_ = 1
-    _fields_ = [
+    _fields_: ClassVar = [
         ("description", ctypes.c_char_p),
         ("taskId", ctypes.c_ushort),
         ("taskCycle", ctypes.c_ulong),
diff --git a/src/pycanape/cnp_api/cnp_prototype.py b/src/pycanape/cnp_api/cnp_prototype.py
index 06a5a40..776e5e6 100644
--- a/src/pycanape/cnp_api/cnp_prototype.py
+++ b/src/pycanape/cnp_api/cnp_prototype.py
@@ -31,7 +31,7 @@ def get_last_error(result, function, args):
 
     if error_code > 0:
         error_msg = (
-            f"{cnp_constants.ErrorCodes(error_code).name}: "  # type: ignore[union-attr]
+            f"{cnp_constants.ErrorCodes(error_code).name}: "
             f"{ptr.contents.value.decode('ascii')}"  # type: ignore[union-attr]
         )
         raise CANapeError(error_code, error_msg, function.__name__)
diff --git a/src/pycanape/utils.py b/src/pycanape/utils.py
index 063b033..8196efa 100644
--- a/src/pycanape/utils.py
+++ b/src/pycanape/utils.py
@@ -5,16 +5,23 @@
 import ctypes
 import logging
 import winreg
+from collections.abc import Callable
 from ctypes.util import find_library
 from threading import Lock
+from typing import Any, ParamSpec, TypeVar
 
 import psutil
 
 LOG = logging.getLogger(__name__)
 LOCK = Lock()
 
+P1 = ParamSpec("P1")
+T1 = TypeVar("T1")
 
-def _synchronization_wrapper(func, func_name: str):
+
+def _synchronization_wrapper(
+    func: Callable[P1, T1], func_name: str
+) -> Callable[P1, T1]:
     """Use locks to assure thread safety.
 
     Without synchronization it is possible that Asap3GetLastError
@@ -46,7 +53,7 @@ def __init__(self, library_or_path: str) -> None:
     def function_type(self):
         return ctypes.WINFUNCTYPE
 
-    def map_symbol(self, func_name: str, restype=None, argtypes=(), errcheck=None):
+    def map_symbol(self, func_name: str, restype=None, argtypes=(), errcheck=None) -> Callable[..., Any]:  # type: ignore[no-untyped-def]
         """
         Map and return a symbol (function) from a C library. A reference to the
         mapped symbol is also held in the instance
@@ -81,7 +88,7 @@ def map_symbol(self, func_name: str, restype=None, argtypes=(), errcheck=None):
 
 
 class CANapeError(Exception):
-    def __init__(self, error_code, error_string, function) -> None:
+    def __init__(self, error_code: int, error_string: str, function: str) -> None:
         #: The error code according to :class:`~pycanape.cnp_api.cnp_constants.ErrorCodes`
         self.error_code = error_code
         super().__init__(f"{function} failed ({error_string})")