What problem does it solve? Tracking machine learning experiments manually across notebooks and scripts leads to lost configurations, uncomparable runs, and no reproducibility. This Skill provides complete guidance for instrumenting training code with Weights & Biases so every metric, hyperparameter, and model checkpoint is logged, versioned, and comparable. ## Core Features & Use Cases - Experiment Tracking: Initialize runs with wandb.init, log metrics, media, histograms, and tables, and compare runs in real-time dashboards. - Hyperparameter Sweeps: Automate optimization with grid, random, and Bayesian search strategies, including hyperband early termination and parallel multi-GPU agents. - Artifacts & Model Registry: Version datasets and models with lineage tracking, aliases for deployment stages, and a central registry for governance. - Framework Integrations: Ready-made patterns for PyTorch, PyTorch Lightning, HuggingFace Transformers, Keras/TensorFlow, Fast.ai, XGBoost, and LightGBM. - Use Case: A team fine-tuning a BERT classifier runs a 50-trial Bayesian sweep over learning rate and batch size, then promotes the best model artifact to a production registry alias. ## Quick Start Ask the agent to instrument your PyTorch training script with W&B experiment tracking, logging loss and accuracy per epoch and saving the final model as a versioned artifact.