What problem does it solve? Machine learning teams lose track of experiments, hyperparameters, and model versions when training runs are scattered across notebooks and scripts. This Skill provides complete guidance for instrumenting training code with Weights & Biases so every run, metric, and artifact is logged, comparable, and reproducible. ## Core Features & Use Cases - Experiment Tracking: Log metrics, configs, media, and system stats from PyTorch, TensorFlow, Keras, HuggingFace, PyTorch Lightning, Fast.ai, XGBoost, and LightGBM training loops. - Hyperparameter Sweeps: Run grid, random, or Bayesian optimization searches with early termination (Hyperband) and parallel multi-GPU agents. - Artifacts & Model Registry: Version datasets and models with automatic lineage tracking, aliases for deployment stages, and a central registry for promotion workflows. - Use Case: A data scientist fine-tuning a BERT classifier can launch a Bayesian sweep over learning rate and batch size, compare 50 runs in a real-time dashboard, and promote the best checkpoint to a production model registry. ## Quick Start Ask the AI to instrument your PyTorch training script with wandb so that losses, accuracy, and the final model checkpoint are logged to a W&B project.