Companies often run customer service chatbots on a large rented AI model (a large language model, or LLM): costly, and outside the operator's control. Swapping in a smaller in-house model is not one-off work: it fails on rare situations, and business policies keep changing.
A 31-billion-parameter open model was first trained on recorded conversations, then served live traffic alongside the incumbent. Reviewers judged its failures independently, deciding whether the fault lay with the model or with a tool or written procedure. Model faults were corrected and the model retrained to make the corrected choice, with the diagnosis supplied as a hint.
After five rounds its failure rate fell below the incumbent's and customer satisfaction matched it.
