Prompt Injection Defense — AI Glossary

Prompt injection defense refers to the techniques and strategies used to protect AI systems from prompt injection attacks, where malicious inputs attempt to override the model's original instructions. Defenses operate at multiple layers — from input validation and output filtering to architectural designs that separate trusted instructions from untrusted user content. No single defense is foolproof, so modern approaches use a layered "defense-in-depth" strategy combining probabilistic and deterministic mitigations.