Headroom Before Protocol Effects: A Decision Procedure for Human-Agent Evaluation

A team protocol has no interpretable benefit without a matched no-protocol baseline and decision-relevant headroom. We present a reporting method that tests admissibility, identifies the marginal contrast, evaluates opportunity, and maps paired uncertainty to an operational action. It distinguishes exact headroom on a fixed battery from uncertain population headroom used in planning. A published meta-analysis of human-AI experiments illustrates why the estimand matters: the same evidence supports augmentation relative to humans alone but contradicts synergy relative to the better constituent. Neither comparison identifies a coordination protocol without a matched no-protocol team. An executable synthetic application further shows that a promising point estimate can remain operationally unresolved once paired uncertainty is considered, and that near-perfect pilot performance does not by itself make a modest benefit impossible. Several inherited multi-model summaries fail the method's artifact gates, so they do not validate it. This is a bounded position and reporting contribution rather than an adoption-ready standard. Human-facing claims still require direct human outcomes, and we introduce no new human experiment.