Codex is OpenAI’s coding agent, and it earns its place working beside Claude Code rather than replacing it. In a codebase it inspects files, makes edits, runs commands, and reviews a change before it becomes a pull request. One model shouldn’t be the whole team.
Picture a second reviewer at the same desk. The first person has worked the file all day, made decisions, and built momentum. The second comes in fresh, opens the same folder, and catches what the first missed. The review is concrete because both of them are looking at the same work.
Why you care
Different models have different tendencies, so having Codex review Claude beats asking one model to grade its own homework. That’s the heart of cross-model review: Claude builds, Codex reviews, Claude fixes, Codex checks again. When AI makes the first draft cheap, review matters more. Plausible work piles up fast, and a second model gives you another set of eyes before anything reaches a client, a repo, or production. The pattern extends past code: if the work lives in files, Codex can help check it.