AI's damage shows up at review, and a single approver has nothing downstream to catch it

An approval leaves the same trace whether or not anyone read the diff. CI stays green, the branch merges, the queue moves. Nothing in the pipeline separates a change that was understood from one that merely looked like something the reviewer would have written himself ^[1], so approval latency and pass rate hold steady while the thing they stand in for drains away.

The loss becomes visible only at the second reader. With two reviewers, an unread approval is one layer of a two-layer catch, and the second layer is where it surfaces. The dev.to account is the other configuration: his own projects, nobody downstream of him, one gate, and by his description the gate had stopped reading ^[2].

METR's trial is the strongest test of self-knowledge in this material. Sixteen experienced developers, 246 real tasks, repositories carrying an average of five years of their own contributions ^[8]. Afterwards they put themselves at roughly 20 percent faster; the measurement said 19 percent slower, a 39-point miss on work they had just finished ^[9][10]. That is not a wrong opinion about a tool.

The aviation research explains why the damage lands on review rather than on authorship. Casner and colleagues found that hand-flying survived automation, and what cratered were the cognitive skills: knowing where the aircraft actually was, what the next step should be, what a failing instrument looked like ^[5]. Macnamara's 2024 review argues the AI case should be worse, because AI substitutes for cognitive work and cognitive skills decay faster than physical ones ^[7]. It also names why nobody catches it in themselves: ordinary decay is noticed because you stopped doing the task, and this decay hides because you kept shipping and only the engagement stopped ^[11].

What none of this material contains is a defect rate. The Stack Overflow figure counts developers reporting lost confidence in their own problem-solving ^[4], not bugs that escaped. The r/ExperiencedDevs thread counts agreement, four hundred replies to one person calling himself a tourist in his own codebase ^[3]. METR measured time, not review quality ^[9]. The author is straight about where that leaves the argument: the diagnosis is done, and every remedy anyone proposes has the same shape, a shape known to fail, including the one he spent two weeks designing ^[12].

The one intervention in the record aimed at automation decay rather than at tooling is the FAA's, which was to recommend pilots hand-fly the majority of flights ^[6]. It works by spending the automation's benefit back on purpose. A review process that wants the same effect has to buy the reps the same way, and pay for them out of the same budget the assistant was supposed to fill.