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Cross-Model LLM Code Review: Should you use Claude to review Codex or vice versa (arxiv.org)
3 points by mil22 60 days ago | hide | past | pdf | 2 comments on HN

In plain words: A study tested having one coding agent review another's draft code on 116 programming tasks, without running any tests. Claude reviewing Codex drafts raised the share of tasks passing tests by about 18 points, while Codex reviewing Claude drafts made things worse.

Abstract · Cross-Model LLM Code Review: Should you use Claude to review Codex or vice versa?

Developers increasingly use two coding agents together: one writes a draft, and the other reviews it. However, it is not clear whether the pairing is worth its cost and time, or whether the order of the pairing matters. We run a controlled experiment on 116 recent hard and medium lcb tasks with Claude and Codex across six conditions to approximate a software practitioner's workflow: both solo baselines, both cross-model orderings, and both same-model orderings. The reviewer sees the problem and the writer's draft but cannot execute tests, which approximates a code review step. Claude review raises Codex drafts from 71.6% to 89.7% ($p_{BH}=.001$); Codex self review raises them to 84.5% ($p_{BH}=.022$). The reverse direction does not pay off: Codex reviewing Claude drafts drops the pass rate from 91.4% to 82.8% ($p_{BH}=.046$), and Claude self review leaves the 91.4% baseline unchanged. Our evaluation indicates that the useful pairing is asymmetric: use Claude to review Codex, not the other way around.

Zuodong Xiang, Yike Zhang, YueMing Zhang, Hailu Xu
arXiv:2607.21656 · cs.SE, cs.AI · submitted Jul 22, 2026
abstract · pdf · html · This paper had been accepted by Agentic SE @ KDD'26

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I love this experiment. I think that the reviewer procedure can be improved with CLAR (e.g., the Impasse skill) or something similar, so I hope they try other approaches to their experiment.
From the original paper abstract:

“Claude review raises Codex drafts from 71.6% to 89.7%; Codex self review raises them to 84.5%. The reverse direction does not pay off: Codex reviewing Claude drafts drops the pass rate from 91.4% to 82.8%, and Claude self review leaves the 91.4% baseline unchanged.”

The highest pass rate was to use just Claude, at 91.4%. Claude reviewing Claude did not improve the pass rate.