Vanna.AI is a Python-based AI SQL agent that simplifies the process of generating SQL queries from natural language inputs using large language models (LLMs). It is designed to be highly accurate on complex datasets and provides robust security features. The tool can be used to connect to various databases, train a RAG (Retrieval-Augmented Generation) model on your data, and then ask questions that return SQL queries, which can be set up to run automatically.