diff --git a/quaddtype/numpy_quaddtype/_quaddtype_main.pyi b/quaddtype/numpy_quaddtype/_quaddtype_main.pyi
index f5e8d680..eab36b39 100644
--- a/quaddtype/numpy_quaddtype/_quaddtype_main.pyi
+++ b/quaddtype/numpy_quaddtype/_quaddtype_main.pyi
@@ -4,8 +4,14 @@ import numpy as np
 from typing_extensions import Never, Self, override
 
 _Backend: TypeAlias = Literal["sleef", "longdouble"]
-_IntoQuad: TypeAlias = QuadPrecision | float | str
-_CastsQuad: TypeAlias = _IntoQuad | np.floating[Any] | np.integer[Any] | np.bool_
+_IntoQuad: TypeAlias = (
+    QuadPrecision
+    | float
+    | str
+    | np.floating[Any]
+    | np.integer[Any]
+    | np.bool_
+)  # fmt: skip
 
 @final
 class QuadPrecDType(np.dtype[QuadPrecision]):  # type: ignore[misc, type-var]  # pyright: ignore[reportGeneralTypeIssues, reportInvalidTypeArguments]
@@ -64,8 +70,15 @@ class QuadPrecDType(np.dtype[QuadPrecision]):  # type: ignore[misc, type-var]  #
     @override
     def __getitem__(self, key: Never, /) -> Self: ...  # type: ignore[override]
 
+# NOTE: Until `QuadPrecision` will become a subclass of `np.generic`, this class cannot
+# be considered "type-safe".
 @final
-class QuadPrecision:  # NOTE: It doesn't inherit from `np.generic` which is type-unsafe
+class QuadPrecision:
+    # NOTE: At runtime this constructor also accepts array-likes, for which it returns
+    # `np.ndarray` instances with `dtype=QuadPrecDType()`.
+    # But because of mypy limitations, it is currently impossible to annotate
+    # constructors that do no return instances of their class (or a subclass thereof).
+    # See https://github.com/python/mypy/issues/18343#issuecomment-2571784915
     def __new__(cls, /, value: _IntoQuad, backend: _Backend = "sleef") -> Self: ...
 
     # Rich comparison operators
@@ -80,16 +93,16 @@ class QuadPrecision:  # NOTE: It doesn't inherit from `np.generic` which is type
     def __ge__(self, other: _IntoQuad, /) -> bool: ...
 
     # Binary operators
-    def __add__(self, other: _CastsQuad, /) -> Self: ...
-    def __radd__(self, other: _CastsQuad, /) -> Self: ...
-    def __sub__(self, other: _CastsQuad, /) -> Self: ...
-    def __rsub__(self, other: _CastsQuad, /) -> Self: ...
-    def __mul__(self, other: _CastsQuad, /) -> Self: ...
-    def __rmul__(self, other: _CastsQuad, /) -> Self: ...
-    def __pow__(self, other: _CastsQuad, mod: None = None, /) -> Self: ...
-    def __rpow__(self, other: _CastsQuad, mod: None = None, /) -> Self: ...
-    def __truediv__(self, other: _CastsQuad, /) -> Self: ...
-    def __rtruediv__(self, other: _CastsQuad, /) -> Self: ...
+    def __add__(self, other: _IntoQuad, /) -> Self: ...
+    def __radd__(self, other: _IntoQuad, /) -> Self: ...
+    def __sub__(self, other: _IntoQuad, /) -> Self: ...
+    def __rsub__(self, other: _IntoQuad, /) -> Self: ...
+    def __mul__(self, other: _IntoQuad, /) -> Self: ...
+    def __rmul__(self, other: _IntoQuad, /) -> Self: ...
+    def __pow__(self, other: _IntoQuad, mod: None = None, /) -> Self: ...
+    def __rpow__(self, other: _IntoQuad, mod: None = None, /) -> Self: ...
+    def __truediv__(self, other: _IntoQuad, /) -> Self: ...
+    def __rtruediv__(self, other: _IntoQuad, /) -> Self: ...
 
     # Unary operators
     def __neg__(self, /) -> Self: ...