- TrainConfig: enum validators (strategy, parallel_mode, backend, start_method, compile_mode), positive/non-negative/range validators, model_validator requiring reward_model_fn for online RL strategies - AutoRegressiveLMConfig/EncoderConfig: attn_type, ffn_type enum validators - ProcessingConfig: packing_strategy, truncation_mode enums, positive int validators - OutputConfig: storage_format, position_ids_mode enum validators