Residual Labor Ledger

Residual Labor Ledger is a costing discipline: before pricing an AI voice agent retainer, count the human work that survives deployment. Every voice deployment leaves a tail of tasks (transcript review, escalation handling, consent logging, prompt repair after a bad call) and that tail, not the per-minute rate, decides whether the retainer holds margin. The framework asks agencies to log four numbers per client: calls handled without touch, escalations per 100 calls, minutes of human review per call, and cost per resolved call. Trillet's audit-trail design and identity verification reduce the review tail in regulated verticals, while Goodcall-style self-serve builds shift more repair work onto the agency. Forrester's 2027 predictions warn that AI budgets face P&L scrutiny rather than pilot credit, so a retainer priced on usage cost alone will look profitable in month one and thin by month six. Price after the ledger, not before.