I made two AIs review each other's code for 30 days. A human still caught the bug in 5 minutes.

Last month I let AI write 100% of my code for 30 days. The single loudest lesson wasn't "AI is amazing" or "AI is useless." It was one sentence: the thing that writes the code can never be the thing that reviews it. A model grades its own homework and it always passes.

So this month I did the obvious next experiment. If the author can't be the reviewer — fine. Make a second AI the reviewer. Author agent writes the feature. A separate skeptic agent tries to tear it apart. No human in the review loop at all, on purpose, to find out how far the structure alone could carry me.

It worked far better than I expected. Right up until the one moment it mattered most.

The setup

Two agents, deliberately given different jobs — because I'd already learned the hard way that "independence" is not a second prompt to the same model asking "is this correct?" It just agrees with itself in a calmer voice.