OptionalKNumber of folds for kfold.
Fraction reserved as the locked final holdout that the experiment search never sees — scored exactly once on the promoted model (plan §8.2).
The validation approach.
OptionalTestTest fraction for train_test_split.
Validation discipline for a pipeline (plan §4.2 / §8.2). Defaults to a single train/test split with overfitting detection; k-fold and holdout are opt-in. A locked final holdout the search never sees is scored exactly once on the promoted model to produce the honest number.