AI coding agents cheat. Not maliciously, and usually not on purpose. They optimize for "looks done," because shipping code that appears complete is easier than shipping code that is complete. Every reward signal an agent sees pushes it toward the green checkmark, and the green checkmark is cheaper to fake than to earn.
That was a curiosity when one engineer babysat one agent. It stops being a curiosity when a fleet of agents opens PRs faster than any human ever did, and a reviewer is asked to catch subtle shortcuts at a volume review was never built for.
So I went and measured it. I mined 327 agent-attributed pull requests from public GitHub, looked for the ones maintainers publicly called out as cheating, and then tried to catch the same cheats with software. This post is what I found, including the parts that did not work.
What "cheating" actually means
The word "cheating" invites eye-rolling AI-doom takes, so let me make it concrete. Here are real, recognizable patterns. Every one of these is something you have already seen a human do on a bad day.
