How to combine Codex and Claude Code with one plugin

Quick Summary
OpenAI’s openai/codex-plugin-cc lets developers call Codex directly from Claude Code for code review, adversarial design review, independent task delegation, or full session transfer. This guide covers installation, explains when to use /codex:review, /codex:rescue, and /codex:adversarial-review, and shows how status, result, and cancel keep background jobs visible. The integration reduces tab switching and repeated context handoffs between the two tools. Clear role assignment and narrow task scopes remain essential, however, and the optional review gate requires active monitoring because a Claude/Codex loop can consume usage limits quickly.
Is anyone else using Codex and Claude Code side by side? I only recently discovered the Codex plugin for Claude Code, published by OpenAI itself. The useful part is not simply having another AI available. It is being able to call Codex from the current Claude Code session for a code review, an adversarial design challenge, or a separate delegated task without constantly switching tabs and sessions.
What makes the Codex plugin for Claude Code useful?
The openai/codex-plugin-cc plugin is intended for developers who already work in Claude Code and want to add Codex to that workflow. Instead of allowing both agents to edit the same file at the same time, you can assign clear roles: Claude Code implements and Codex reviews, or Claude Code keeps the main thread while Codex investigates an independent problem in the background.
The official plugin provides review commands such as /codex:review and /codex:adversarial-review, delegation through /codex:rescue, and job or session management through /codex:transfer, /codex:status, /codex:result, and /codex:cancel. Codex therefore becomes a collaborator inside the Claude Code workflow rather than a separate window.
It does not create a separate Codex runtime
The plugin uses the Codex CLI and Codex app server installed on the same machine. It also reuses the local authentication state, current repository checkout, and existing config.toml settings. Integration is straightforward, but each request still contributes to the user's Codex usage limits.
Requirements before installation
You need Node.js 18.18 or later and either a ChatGPT subscription, including Free, or an OpenAI API key. If Codex CLI is missing, /codex:setup can offer installation guidance. You can also install it manually with npm install -g @openai/codex and sign in with !codex login.
How to install the Codex plugin in Claude Code
Run these commands in Claude Code:
/plugin marketplace add openai/codex-plugin-cc/plugin install codex@openai-codex/reload-plugins/codex:setup
The last command checks whether Codex is installed and authenticated. Once setup is complete, the Codex slash commands should appear in Claude Code, along with the codex:codex-rescue agent under /agents.
Try a background review first
A low-risk first run is /codex:review --background. Use /codex:status to monitor it and /codex:result to retrieve the final review. Multi-file reviews can take time, so background mode keeps Claude Code available for other work.
Three effective Codex and Claude Code workflows
The value of the plugin comes from role design. If both agents modify the same area without boundaries, the result may be conflicting edits, repeated analysis, and wasted context. The following workflows make ownership clearer.
Let Claude implement and Codex review
After Claude Code completes a feature, run /codex:review for a read-only review. It can inspect current uncommitted changes or compare the branch against a base with /codex:review --base main. Because Codex does not edit files in this mode, the developer keeps control of what is accepted.
For example, after Claude adds a payment flow across several modules, Codex can inspect logic errors, edge cases, and cross-file side effects. Claude Code can then evaluate the findings and apply only the changes that make sense.
Delegate an entire task to Codex
Use /codex:rescue for a problem that can be isolated, such as /codex:rescue --background investigate why the integration test is flaky. Claude Code can continue working on the interface or documentation while Codex investigates in the background. Rescue supports --background, --wait, --resume, and --fresh.
Define the expected output and file scope before delegating. A vague instruction to fix everything while Claude Code is also editing the repository can still create collisions. A good task has a specific goal, completion criteria, and a clearly owned part of the codebase.
Use adversarial review to challenge the project direction
/codex:adversarial-review is designed to question implementation and design decisions rather than merely find bugs. For example, /codex:adversarial-review --base main challenge the caching and retry design asks Codex to inspect assumptions, trade-offs, alternatives, and risks such as data loss, race conditions, rollback, or reliability.
This is where the two agents may appear to argue, but the debate only helps when a human sets a narrow question, requests evidence, and defines a decision rule. Otherwise, the review can become a chain of opinions with no practical outcome.
Transfer sessions and manage background jobs
/codex:transfer creates a persistent Codex thread from the current Claude Code session and prints a codex resume <session-id> command. It is useful when a discussion has grown beyond a short review and you want to continue directly in the Codex App or TUI without manually rewriting the context.
Monitor, retrieve, and cancel work
For background tasks, /codex:status shows progress, /codex:result returns the stored output and session ID, and /codex:cancel stops an active job. These commands prevent multi-agent work from becoming a black box. When a task drifts from its goal, canceling early is usually cheaper than waiting and starting over.
Watch for review loops and usage limits
A practical safety checklist
- Assign roles before running: one agent implements while the other reviews, or each owns a separate task.
- Limit the scope by naming the branch, files, risk area, and completion criteria.
- Use background mode for large reviews and check progress periodically.
- Enable the review gate only while actively monitoring it, then disable it with
/codex:setup --disable-review-gate. - Do not let Claude review all Codex output and then ask Codex to review every Claude revision without a clear stopping rule.
- Use
/codex:cancelwhen a task moves in the wrong direction.
How can Codex and Claude Code work well together?
The official OpenAI plugin offers a cleaner alternative to keeping Codex and Claude Code open in separate tabs or letting both agents edit the same file. Claude Code can remain the coordinator while Codex reviews, challenges a design, or owns a separate task. A sensible starting point is one small /codex:review --background run, followed by status, result, and cancel. Try rescue, transfer, and the review gate only after the basic workflow is familiar. The two systems can complement each other well, provided a person still sets the boundaries, budget, and stopping point.



