I shipped an AI-generated PR that violated four of our own architecture decisions. Nobody caught it

`--- title: "I shipped an AI-generated PR that violated four of our own architecture decisions. Nobody caught it." published: false description: "AI coding agents don't make architectural mistakes. They make architecturally unconstrained outputs — and PR review was never sized for the throughput." tags: ai, architecture, devops, productivity The PR was 812 lines. Eleven files. Tests green. Generated by Cursor with Claude Sonnet behind it, lightly cleaned up by a mid-level engineer, approved in eight minutes by a senior who had four other PRs queued behind it. It reintroduced langchain. The team had ripped langchain out six weeks earlier. There was an ADR. There was a Slack thread. There was a tagged release. None of that information was anywhere near the system that generated the code, and none of it was anywhere near the system that reviewed it. The diff didn't say "I'm reintroducing a banned dependency." It said from langchain.chains import LLMChain on line 41 of a ut