Lost cumulatively hours on these things this months.

MODEL_CONFIG = ConfigDict(
    serialize_by_alias=True,  # why doesn't this, alone, work?
)

Guess why? Because I have pydantic 2.10, the config above was introduced in 2.11, and it just quietly allows me to set this config value. (Configuration - Pydantic) (Ty ty for picking up on this)

Next. Configuration - Pydantic

ConfigDict(
    arbitrary_types_allowed=False,  # disallow obj.invalid_field = "whatever"
)

For my own models as well. Setting obj.name='test' when you want obj.step_name is almost never a good idea.

And again about serialize_by_alias: will be default in pydantic v3, which I welcome, because if you forget to model_dump(by_alias=True) then the model will be dumped with unexpected names, which will then be quietly deleted when you try to initialize a new model from that dict through e.g. NewModel(**old_model.model_dump()). (Should’ve validated anyway, but…)