Probability Contracts: Accuracy, Coherence, and Decisions Across LLM Interfaces

תקציר מקורי באנגליתarXiv:2609.37470v1 Announce Type: new Abstract: A probability used for a decision should refer to the same event across equivalent requests. We introduce probability contracts, a benchmark connecting exact finite-world posteriors, validated event transformations, and failure-aware decision evaluation. Four model-interface configurations are evaluated on 1,000 worlds. Their assessments differ across accuracy, coherence, and decision loss: Kev has lower aggregate canonical posterior error than Jev, but larger complement and coarsening residuals, with accuracy ordering varying by stratum. Jev's Event and Choice interfaces induce different binary actions on 32.8% of valid pairs at defer cost 0.10. A post-hoc analysis finds that disagreement certifies only 11-52% of mean binary pair error acros