Text-to-SQL Agents 2026: Vanna, LangGraph & Eval Loops
Text-to-SQL agents finally work in 2026. Learn how Vanna, LangGraph, and eval loops turn a text-to-sql agent into verified, trustworthy production queries.
Chapter 1: Why Text-to-SQL Broke, and Why 2026 Agents Finally Work For most of the last three years, text-to-SQL was the demo that killed the deal. You showed a stakeholder a chat box, typed "what was revenue last quarter," and out came a query that ran, returned a number, and looked correct. Then someone from finance asked why it disagreed with the dashboard by eleven percent, and the entire project got quietly reclassified as "exploratory." That failure was not a model quality problem. GPT-4-class models could already write competent SQL in 2023. The failure was architectural: we were asking a...