How to Stop an AI Agent from Inventing Nigerian Postcodes
On 1 October 2026, Nigeria's postcode changed from six digits to an 11-character code that identifies a single building, such as EK-01-A03-FK-01 . Language models trained before that date still describe the old format with full confidence. That affects two kinds of agent: a coding agent that writes your validation code, and a runtime agent that reads a postcode from a customer's message or fills in a delivery form. This article shows you how to contain both....
On 1 October 2026, Nigeria's postcode changed from six digits to an 11-character code that identifies a single building, such as EK-01-A03-FK-01 . Language models trained before that date still describe the old format with full confidence. That affects two kinds of agent: a coding agent that writes your validation code, and a runtime agent that reads a postcode from a customer's message or fills in a delivery form. This article shows you how to contain both....