This article is missing an incredibly important detail: what is the harness doing?

I get remarkably good results using any recent OpenAI model using the codex-rs harness pointing at a built checkout of the PR. The models use the available tools (i.e. the shell) to understand the repo. I get some false positives and some false negatives, but I don’t believe for a second that I would get comparable performance using a dramatically less capable harness. (Also, the models read the short AGENTS.md for some context as to what’s going on. The prompt I use is about one sentence. I don’t bother with the built in review tool.)