Context Engineering, Not Retrieval: Why Your Agentic RAG Fails in Production

Last quarter I watched a revenue forecasting agent confidently report that Q3 was up 14% year-over-year. The CFO loved it. The board saw it. Then someone in data engineering pointed out the number was wrong. Not wrong like rounding-error wrong. Wrong because the agent pulled “revenue” from two systems that define the word differently. The CRM tracks bookings. The data warehouse tracks recognized revenue under ASC 606. The agent retrieved both, averaged them, and presented the result with zero hesitation and a citation to boot. Nobody caught it for three weeks.