What problem does it solve? Aligning language models with human preferences requires complex post-training pipelines (RLHF) that are difficult to configure correctly. This Skill provides ready-to-use workflows for supervised fine-tuning, preference alignment, reward model training, and online reinforcement learning using HuggingFace TRL. ## Core Features & Use Cases - Full RLHF Pipeline: Step-by-step checklists for SFT → reward model → PPO training with working code for each stage. - Preference Alignment with DPO: Train on chosen/rejected pairs without a reward model, with 10+ loss variants (IPO, hinge, robust, APO) documented in references. - Memory-Efficient Online RL: GRPO training with custom reward functions for GPU-constrained environments. - Use Case: You have a dataset of preferred vs. rejected chatbot responses. Use the DPO workflow to align a Qwen2.5 model with those preferences, tune the beta parameter, and evaluate the aligned model. ## Quick Start Fine-tune Qwen2.5-0.5B with DPO on the ultrafeedback preference dataset using TRL and show me the training configuration.