DHH's adversarial review is one sentence typed into Codex
Two coding agents, no orchestration layer, one instruction each way.
DHH posted his technique for adversarial code review and it fits in a sentence. When he is driving from Codex, he types "Review this with claude". When he is in Claude, he types "Review this with codex".
Models know how to to kick off a review using the cli. Know how to take turns. Know how to settle an argument. No magic.
That is the whole setup. He says the models already know how to kick off a review using the CLI, know how to take turns, and know how to settle an argument. His sign-off on the technique is two words. No magic.
Why the short version matters
The interesting part is not that one model checks another's work. It is that DHH is not building anything to make it happen. There is no harness, no custom workflow, no script holding the two agents together and passing messages between them. He tells the agent he is already talking to that a second agent exists, and the agent handles the rest through the command line.
For a solo founder, the practical read is that the second reviewer is already sitting in your monthly bill. If you pay for both a Codex subscription and a Claude subscription, the adversarial pass costs you a sentence rather than a side project. You do not need to pick a winner between the two tools, and you do not need to maintain glue code that breaks every time either CLI changes.
It also lands in an argument that has been running for a while among the people we follow. Arvid Kahl has described an earlier version of the same idea with more structure around it, including a third agent acting as arbiter when the first two disagree. DHH's version strips that out and trusts the models to settle it themselves.
One caveat worth keeping. This is one founder describing his own habit in a single post, not a benchmark, and he gives no numbers on how often the second model catches something the first one missed. Nobody has published that yet. What DHH is claiming is narrower and easier to test for yourself, that the coordination you were about to build is already there.