from typing import Annotated
from typing_extensions import TypeAliasType

from pydantic import Field, BaseModel

SomeAlias = TypeAliasType('SomeAlias', Annotated[int, Field(description='number')])

class Model(BaseModel):
    foo: Annotated[SomeAlias, Field(title='abc')]


print(Model.model_json_schema())  # description gets dropped