I told one AI to demolish the handoff prompt I wrote for another AI. It found a test that passes even when it's empty

I'm building an app with Claude Code right now. The setup is a little unusual. One "commander" session writes the instructions, and separate "worker" sessions implement them in parallel. The commander never touches the keyboard itself. Its whole job is to turn "what to do next" into a handoff prompt that a worker can read and just run with. And that handoff prompt is quietly the scariest thing in the whole loop. The moment I hand it over, the worker trusts it as the spec and starts sprinting. If the spec is wrong, the wrong thing gets built. Fast, and with confidence. Before handing it over, I did my usual ritual I've picked up a habit lately. Before I throw the instructions at a worker, I run them past a subagent whose entire job is to demolish them. It's defined to never approve, to hunt for holes, and to never, ever close with "this looks broadly reasonable." What was different this time: this thing didn't just read the prose of my prompt. It went and read the actual code. And the reply it came back with made my stomach drop a little. Objection 1: I wrote "make the test pass (go green)", but that test's green meant nothing In the instructions, I'd written this as a definition of done: "Get the XX test passing (green)." The demolition agent's answer: "That test goes green even when the thing it's testing fails. " I read it. It was true. The test only checks "did the process run all the way to the end." It never checks the one thing that matters: did it succeed? Fail, and as long as it "returned a failure result and finished running," green. On top of that, the batch path was swallowing exceptions, so no matter what blew up, still green. So even if a worker reported back "DoD met, tests green!", nothing was actually proven. The completion criterion I wrote myself was an empty pass. Objection 2: I wrote "just flip a flag", but that switch didn't exist One more. I'd written " flip a config flag and it swaps in the real component ", as if it were a feature that alread