What problem does it solve? Machine learning training runs produce scattered metrics, configs, and checkpoints that are hard to compare, reproduce, or share. This Skill provides complete guidance for instrumenting training code with Weights & Biases so every experiment is logged, visualized, and versioned automatically. ## Core Features & Use Cases - Experiment Tracking: Log metrics, configs, media, and system stats from PyTorch, TensorFlow, Keras, HuggingFace, and PyTorch Lightning training loops. - Hyperparameter Sweeps: Run grid, random, or Bayesian searches with early termination and parallel agents across multiple GPUs. - Artifacts & Model Registry: Version datasets and models with lineage tracking, aliases, and promotion through staging to production. - Use Case: A team fine-tuning a BERT classifier can launch a Bayesian sweep over learning rate and batch size, compare 50 runs in a shared dashboard, and promote the best checkpoint to the production model registry. ## Quick Start Instrument my PyTorch training script with W&B logging and set up a Bayesian hyperparameter sweep over learning rate and batch size.