When using Flask-Smorest, you can disable the automatic documentation of default error responses across all endpoints using this configuration pattern example:

def setup_api(app: Flask, version: str = "v1"):
    # init API
    _api = Api(
        spec_kwargs={
            "title": f"{app.config['API_TITLE']} {version}",
            "version": f"{version}.0",
            "openapi_version": app.config["OPENAPI_VERSION"],
        },
        config_prefix=version.upper(),
    )
    _api.DEFAULT_ERROR_RESPONSE_NAME = None # Key parameter to disable default errors
    _api.init_app(app)
    # register blueprints
    register_blueprints(_api, version)