diff --git a/pyproject.toml b/pyproject.toml
index a183e5b..25caa42 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "danom"
-version = "0.10.2"
+version = "0.10.3"
 description = "Functional streams and monads"
 readme = "README.md"
 license = "MIT"
diff --git a/src/danom/_result.py b/src/danom/_result.py
index dcbfe86..2c22def 100644
--- a/src/danom/_result.py
+++ b/src/danom/_result.py
@@ -5,7 +5,10 @@
 from types import TracebackType
 from typing import (
     Any,
+    Concatenate,
+    Generic,
     Literal,
+    Never,
     ParamSpec,
     Self,
     TypeVar,
@@ -20,12 +23,12 @@
 F_co = TypeVar("F_co", bound=object, covariant=True)
 P = ParamSpec("P")
 
-Mappable = Callable[P, U_co]
-Bindable = Callable[P, "Result[U_co, E_co]"]
+Mappable = Callable[Concatenate[T_co, P], U_co]
+Bindable = Callable[Concatenate[T_co, P], "Result[U_co, E_co]"]
 
 
 @attrs.define(frozen=True)
-class Result(ABC):
+class Result(ABC, Generic[T_co, E_co]):
     """`Result` monad. Consists of `Ok` and `Err` for successful and failed operations respectively.
     Each monad is a frozen instance to prevent further mutation.
     """
@@ -67,7 +70,7 @@ def is_ok(self) -> bool:
         ...
 
     @abstractmethod
-    def map(self, func: Mappable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
+    def map(self, func: Mappable, *args: P.args, **kwargs: P.kwargs) -> Result[U_co, E_co]:
         """Pipe a pure function and wrap the return value with `Ok`.
         Given an `Err` will return self.
 
@@ -81,7 +84,7 @@ def map(self, func: Mappable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
         ...
 
     @abstractmethod
-    def map_err(self, func: Mappable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
+    def map_err(self, func: Mappable, *args: P.args, **kwargs: P.kwargs) -> Result[U_co, E_co]:
         """Pipe a pure function and wrap the return value with `Err`.
         Given an `Ok` will return self.
 
@@ -95,7 +98,7 @@ def map_err(self, func: Mappable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
         ...
 
     @abstractmethod
-    def and_then(self, func: Bindable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
+    def and_then(self, func: Bindable, *args: P.args, **kwargs: P.kwargs) -> Result[U_co, E_co]:
         """Pipe another function that returns a monad. For `Err` will return original error.
 
         .. code-block:: python
@@ -110,7 +113,7 @@ def and_then(self, func: Bindable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
         ...
 
     @abstractmethod
-    def or_else(self, func: Bindable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
+    def or_else(self, func: Bindable, *args: P.args, **kwargs: P.kwargs) -> Result[U_co, E_co]:
         """Pipe a function that returns a monad to recover from an `Err`. For `Ok` will return original `Result`.
 
         .. code-block:: python
@@ -147,27 +150,24 @@ def unwrap(self) -> T_co:
         """
         ...
 
-    def __class_getitem__(cls, _params: tuple) -> Self:
-        return cls  # ty: ignore[invalid-return-type]
-
 
 @attrs.define(frozen=True, hash=True)
-class Ok(Result):
+class Ok(Result[T_co, Never]):
     inner: Any = attrs.field(default=None)
 
     def is_ok(self) -> Literal[True]:
         return True
 
-    def map(self, func: Mappable, **kwargs: P.kwargs) -> Ok[U_co]:
-        return Ok(func(self.inner, **kwargs))
+    def map(self, func: Mappable, *args: P.args, **kwargs: P.kwargs) -> Ok[U_co]:
+        return Ok(func(self.inner, *args, **kwargs))
 
-    def map_err(self, func: Mappable, **kwargs: P.kwargs) -> Ok[U_co]:  # noqa: ARG002
+    def map_err(self, func: Mappable, *args: P.args, **kwargs: P.kwargs) -> Self:  # noqa: ARG002
         return self
 
-    def and_then(self, func: Bindable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
-        return func(self.inner, **kwargs)
+    def and_then(self, func: Bindable, *args: P.args, **kwargs: P.kwargs) -> Result[U_co, E_co]:
+        return func(self.inner, *args, **kwargs)
 
-    def or_else(self, func: Bindable, **kwargs: P.kwargs) -> Ok[T_co]:  # noqa: ARG002
+    def or_else(self, func: Bindable, *args: P.args, **kwargs: P.kwargs) -> Self:  # noqa: ARG002
         return self
 
     def unwrap(self) -> T_co:
@@ -179,7 +179,7 @@ def unwrap(self) -> T_co:
 
 
 @attrs.define(frozen=True)
-class Err(Result):
+class Err(Result[Never, E_co]):
     error: Any = attrs.field(default=None)
     input_args: tuple[()] | SafeArgs | SafeMethodArgs = attrs.field(
         default=(), validator=instance_of(tuple), repr=False
@@ -210,19 +210,19 @@ def _extract_details(self, tb: TracebackType | None) -> list[dict[str, Any]]:
     def is_ok(self) -> Literal[False]:
         return False
 
-    def map(self, func: Mappable, **kwargs: P.kwargs) -> Err[E_co]:  # noqa: ARG002
+    def map(self, func: Mappable, *args: P.args, **kwargs: P.kwargs) -> Self:  # noqa: ARG002
         return self
 
-    def map_err(self, func: Mappable, **kwargs: P.kwargs) -> Err[F_co]:
-        return Err(func(self.error, **kwargs))
+    def map_err(self, func: Mappable, *args: P.args, **kwargs: P.kwargs) -> Err[F_co]:
+        return Err(func(self.error, *args, **kwargs))
 
-    def and_then(self, func: Bindable, **kwargs: P.kwargs) -> Err[E_co]:  # noqa: ARG002
+    def and_then(self, func: Bindable, *args: P.args, **kwargs: P.kwargs) -> Self:  # noqa: ARG002
         return self
 
-    def or_else(self, func: Bindable, **kwargs: P.kwargs) -> Result[U_co, E_co]:
-        return func(self.error, **kwargs)
+    def or_else(self, func: Bindable, *args: P.args, **kwargs: P.kwargs) -> Result[U_co, E_co]:
+        return func(self.error, *args, **kwargs)
 
-    def unwrap(self) -> None:
+    def unwrap(self) -> T_co:
         if isinstance(self.error, Exception):
             raise self.error
         raise ValueError(f"Err does not have a caught error to raise: {self.error = }")
diff --git a/src/danom/_safe.py b/src/danom/_safe.py
index aeefd98..20fb410 100644
--- a/src/danom/_safe.py
+++ b/src/danom/_safe.py
@@ -26,7 +26,7 @@ def add_one(a: int) -> int:
     """
 
     @functools.wraps(func)
-    def wrapper(*args: P.args, **kwargs: P.kwargs) -> Result[U, E]:
+    def wrapper(*args: P.args, **kwargs: P.kwargs) -> Result[U, Exception]:
         try:
             return Ok(func(*args, **kwargs))
         except Exception as e:  # noqa: BLE001
diff --git a/tests/conftest.py b/tests/conftest.py
index 3b46ab1..bf93208 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -3,7 +3,7 @@
 import asyncio
 from multiprocessing.managers import ListProxy
 from pathlib import Path
-from typing import Any, Self
+from typing import Any, NoReturn, Self
 
 from src.danom import safe, safe_method
 from src.danom._result import Err, Ok, Result
@@ -53,7 +53,7 @@ async def async_read_text(path: str) -> str:
 
 
 @safe
-def safe_add(a: int, b: int) -> Result[int, Exception]:
+def safe_add(a: int, b: int) -> int:
     return a + b
 
 
@@ -71,7 +71,7 @@ def safe_double[T: (str, float, int)](x: T) -> T:
 
 
 @safe
-def safe_raise_type_error(_a: Any) -> None:  # noqa: ANN401
+def safe_raise_type_error(_a: Any) -> NoReturn:  # noqa: ANN401
     raise TypeError
 
 
diff --git a/tests/test_safe.py b/tests/test_safe.py
index 008e8ef..a7ab0ae 100644
--- a/tests/test_safe.py
+++ b/tests/test_safe.py
@@ -2,6 +2,7 @@
 
 import pytest
 
+from danom._result import Err
 from tests.conftest import (
     REPO_ROOT,
     Adder,
@@ -71,6 +72,9 @@ def test_traceback():
         "ZeroDivisionError: division by zero",
     ]
 
+    if not isinstance(err, Err):
+        raise TypeError("This should be an Err by now")
+
     tb_lines = err.traceback.replace(str(REPO_ROOT), ".").splitlines()
 
     missing_lines = [line for line in expected_lines if line not in tb_lines]
diff --git a/uv.lock b/uv.lock
index 21eabf1..0db4803 100644
--- a/uv.lock
+++ b/uv.lock
@@ -317,7 +317,7 @@ wheels = [
 
 [[package]]
 name = "danom"
-version = "0.10.2"
+version = "0.10.3"
 source = { editable = "." }
 dependencies = [
     { name = "attrs" },