The Blackwell Dilemma: No Non-Vacuous Information Ordering Exists Under Endogenous Feasibility Constraints

Paper and pre-registered prediction test. When actions are irreversible and quality signals are topology-blind, the Blackwell ordering of information structures breaks down: better signals can make agents strictly worse off. We identify a phase transition at the bond-percolation threshold p_c = 1/2, prove a welfare decomposition W = W_topo + W_info, and show that structural policy dominates information policy by over 40x near the critical point. The prediction note registers three falsifiable predictions in the AI framework ecosystem, with verification scheduled for May 2026. Simulation code: https://github.com/openexecution/blackwell-dilemma