2026.04/AI Safety Theory

The Defense Trilemma: Why Prompt Injection Defense Wrappers Fail?

M. Bhatt, S. Munshi, V. S. Narajala, I. Habler, A. Al-Kahfah, K. Huang, J. Webb, B. Gatto, M. T. Hoque

Abstract

Proves that continuity, utility preservation, and complete safety cannot coexist for prompt-injection wrapper defenses, and characterizes the boundary where every such defense must fail.

Where it sits

Pillar 01 — Impossibility & Boundary Research

What can a defense never guarantee?

Prove where defenses cannot hold — what a control can guarantee, and which design directions are dead ends.

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