A production data analytics system built with language models requires more than prompt-based SQL generation.
A usable system has to do more than translate a question into a query. It needs to represent schema meaning,
retrieve the right context, handle ambiguity, validate queries before execution, protect sensitive data,
observe failures, evaluate changes, and improve over time. In practice, those concerns determine whether a
workflow is reliable, safe, and maintainable.
The implementation uses a practical open-source stack built around Python, LangGraph, LangChain, Hugging Face models, Unsloth for efficient fine-tuning, and VERL with Agent Lightning for reinforcement learning workflows. It also integrates Langfuse for observability and tracing, enabling tracking of agent execution, prompt interactions, model outputs, and system performance during development and evaluation.
This book is for developers, data engineers, and ML engineers who already know basic SQL and want to
build production SQL agent systems from scratch.