Background Part 1 ended with a mistake worth fixing. Meera’s complaint was: “what is SQ \TPR HSPTLTY on my statement? I don’t recognise it at all.” The system flagged it as fraud every single time, with full confidence. And honestly, based on the words alone, that seemed fair. But the real issue wasn’t the prompt - it …

Background In Part 0 we built the system that Meridian Bank already has as an existing banking system: a REST API over PostgreSQL that applies every dispute rule exactly, every time. Run the same request twice, get the same answer twice. That property of building deterministic systems and testing them out comes very …

Background Meera opens her banking app and sees a payment in her transaction history that she doesn't recognise: ₹180 to SQ *TPR HSPTLTY, four days ago. She had never heard of it. So she does the responsible thing - She opens the dispute form of her bank, picks "Unrecognised or fraudulent transaction", types …