OptionalcontextRequest user — threaded for isolation/audit.
The proposed experiment being trained (algorithm × feature set × hyperparameters).
The MJ: Experiment Session Iterations id this run belongs to.
The plan being executed (carries TargetDefinition, SuccessMetric, ValidationStrategy).
OptionalproviderOptional provider for multi-provider correctness.
The owning MJ: Experiment Sessions id.
Input handed to IExperimentTrainer.train for a single iteration.