Modern inference engines routinely treat ingested text as stable evidence, despite the reality that historical and institutional corpora are frequently edited, translated, summarized, or re- framed by power. We introduce Reverse-STP: a source-first solvency gate applied at ingestion that measures closure pressure (e.g., causal bridge injection, psychologizing interiority, teleological inevitability, agency diffusion, and register normalization). The output is a Source Solvency score (SUs) and tier that caps the strength of downstream claims without requiring access to ground truth. Reverse-STP supports retroactive re-auditing, enabling inferability to evolve as detection improves. We provide an IEP/2.0 machine contract (HIST_CLOSURE_AXIS_01), a conservative profile selector across genres, and a change-point comparator for edition drift.