Position: A Three-Layer Probabilistic Assume-Guarantee Architecture Is Structurally Required for Safe LLM Agent Deployment. - Saddek Bensalem; Yi Dong 002; M. Franzle; Xiaowei Huang 001; J. Kroger; Dejan Nickovic; A. Nouri; R. Roy; Changshun Wu (CoRR, 2026)