What problem does it solve? Adapting a pre-trained LLM to a specific domain or task requires navigating method selection, dataset formatting, GPU memory constraints, and alignment training, where missteps waste hours of compute. This Skill provides decision trees, working code, and validated troubleshooting guidance for the full fine-tuning lifecycle. ## Core Features & Use Cases - Parameter-Efficient Fine-Tuning: Implements LoRA and QLoRA pipelines with HuggingFace PEFT and TRL, enabling 7B model tuning on consumer GPUs with as little as 6GB VRAM. - Dataset Preparation and Validation: Converts between Alpaca, ShareGPT, and chat formats, deduplicates records, analyzes token lengths, and splits train/validation sets via the prepare_dataset.py script. - Preference Alignment: Supports DPO training with preference pairs as a simpler alternative to full RLHF pipelines. - Use Case: Fine-tune Qwen3-8B on 5,000 domain-specific instruction examples using QLoRA on a single RTX 4090, then merge the adapter and convert to GGUF for llama.cpp deployment. ## Quick Start Fine-tune Qwen/Qwen3-8B on my train.jsonl dataset using QLoRA with rank 16 and save the adapter to ./qlora-output.