[simonw]

That's a great explanation, especially "Applications occasionally have holes that are accessed using novel attacks, but it is possible to secure an interface in such a way that 100% of known attacks will not affect it." - that's fundamental to the challenge of prompt injection compared to other attacks like XSS and SQL injection.

The thing where people propose a solution, someone shows a workaround, they propose a new solution etc is something I've started calling "prompt injection Whack-A-Mole". I tend to bow out after the first two rounds!