Andrew Nesbitt has written a blog post detailing a recent incident with the jqwik library for property-based testing in Java. On May 25, the 1.10.0 release of jqwik included a change that attempts to instruct coding agents to disregard previous instructions and delete jqwik tests and code.

I think this is a new class of supply-chain input worth keeping an eye on, mostly because of how little of the existing tooling has any opinion about it. A System.out.print of sixty-eight bytes of plain ASCII isn't the kind of thing scanners are looking for, since those watch for install hooks, network calls, filesystem writes, obfuscated strings and the like. The jar makes the same syscalls it made in 1.9, and because the change was committed and released by the legitimate maintainer through the normal build, it's clean from a SLSA point of view too: the provenance is what it should be. Anyone who reads the diff can see what it does, but a patch bump of a test-scoped dependency is not where most projects spend their review time.