Eval Debt Compounding

Eval Debt Compounding treats every untested prompt, tool call, and agent branch as a liability that accrues interest. The first model swap or provider change is when the interest comes due: without a scored baseline, an agency cannot tell whether a regression came from the new model, a prompt edit, or a retrieval change, so the whole delivery gets re-debugged by hand. The framework asks one question before any client AI ships: what is the cost of proving this still works after the next change? Teams that answer with a stored eval set pay once. Teams that answer with manual spot checks pay on every release. The compounding is visible in provider churn: when Replit removed Anthropic models in October 2026, every workflow without a regression suite became an unplanned rebuild. Agencies holding a scored baseline convert that event into a one-day re-run and a change-order conversation, while those without one absorb the rework inside the retainer.