[Python] How do I make mypy treat my class as not being a subtype of object?

I'm trying to write a class in Python where comparisons like MyClass(5) == 5 are considered type errors by mypy, even though in Python all user-defined classes inherit from object.

My goal is to:

1. Restrict comparisons to only instances of MyClass, so that MyClass(5) == 5 triggers a type checker error.
2. Prevent passing MyClass instances into functions that expect generic object parameters, like this:

from typing import Self

class MyClass:
def __init__(self: Self, x: int):
self.x = x

def __eq__(self: Self, other: "MyClass") -> bool:
return self.x == other.x

print(MyClass(5) == 5) # ❌ I want mypy to give an error here

def abstract_comparator(a: object, b: object) -> bool:
return a == b

print(abstract_comparator(MyClass(5), 5)) # ❌ I also want an error here


I tried:

• Adding @overload definitions for __eq__, but mypy still treats MyClass as an object, so abstract_comparator(MyClass(5), 5) is accepted.
• Creating fake protocols or dummy fields, but that either leaks into bar() or allows other unintended side effects.

Ideally, I’d like a way to say “MyClass is not assignable to object” for the purposes of type checking, or a plugin / strict mode in mypy (or another tool like Pyright) that enforces __eq__ type contracts more strictly and disallows structural compatibility with object.

Is there any way to express this intent to mypy or another type checker?

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