Sanitization isn’t enough. We need a way to separate code and data (not just to sanitize out instructions from data) that is deterministic. If there’s a “decide whether this input is code or data” model in the mix, you’ve already lost: that model can make a bad call, be influenced or tricked, and then you’re hosed.

At a fundamental level, having two contexts as suggested by some of the research in this area isn’t enough; errors or bad LLM judgement can still leak things back and forth between them. We need something like an SQL driver’s injection prevention: when you use it correctly, code/data confusion cannot occur since the two types of information are processed separately at the protocol level.