W&B sits between your development environment (where data scientists fine-tune models and engineers build chains) and your production serving layer (where LLMs answer user queries). Its core governance surfaces are:
- Experiment Tracking: Logs prompts, completions, token usage, latencies, and custom metrics from LangChain, LlamaIndex, or custom apps during development and A/B testing.
- Model Registry: Acts as a version-controlled hub for LLM artifacts—base models (GPT-4, Claude 3), fine-tuned adapters (LoRA weights), and embedding models (text-embedding-3-large).
- Artifacts & Lineage: Stores and versions not just model weights, but also prompt templates, evaluation datasets, and vector store indexes, creating a complete, auditable lineage for every prediction.




