Run Claude Code And Codex Together

This is the exact setup to combine Claude Code and Codex in a single workflow: Claude Code as the fast, opinionated builder and Codex as the methodical editor. They are not competing for the same job. The combination ships better code than either tool alone.

What You'll Learn

• The decision tree: which tool to use for planning, coding, reviews, refactors, and debugging
• Codex plugin install for Claude Code in under 30 seconds (then call /codex commands inside any Claude session)
• The Ctrl+J workflow: running Claude Code inside the Codex desktop terminal
• The 5 hand off prompts to switch between them mid session
• Plan combo recommendations for max value at the $20 / $100 / $200 tiers

The Mental Model

Claude Code is your doer. Codex is your editor. Claude moves fast and makes strong opinionated calls. Codex thinks longer and follows your instructions more literally. They are doing different jobs in the same workflow.

Why this beats picking one: most people switching between the two are doing it because their current tool is annoying them on one specific task. The fix is not to switch. The fix is to add the other tool for that specific task. Speed lives in Claude Code. Quality control lives in Codex. Use each for what it is best at.

The Decision Tree

Use this to decide which tool to fire up for which job. It cuts the decision fatigue completely.

Use Claude Code for:

• Vibe coding personal software, side projects, weekend builds
• Building your own Claude skills, plugins, subagents
• Architecture planning and breaking down a complex problem into steps
• Anything where speed matters more than perfection
• Terminal first workflows where you live in the CLI

Use Codex for:

• Production code that has to ship clean the first time
• Adversarial code review of work Claude just produced
• Refactors where you want a methodical second opinion
• Anything where you want the agent to think before it acts
• Long running tasks you can leave the desktop app working on

The pattern to follow: Claude Code drafts the feature. Codex reviews it. Claude Code applies the fixes. Codex re reviews. Ship. The round trip takes less time than over prompting one tool to get it right on the first pass.

Setup 1: Codex Inside Claude Code

If you live in Claude Code and want to add Codex for reviews and rescues, this is the path. OpenAI ships an official Codex plugin for Claude Code that installs in under a minute. Once installed, you can call /codex commands inside any Claude Code session without ever leaving it.

Prerequisites:

• Claude Code installed and working (CLI, desktop app, or IDE extension)
• Node.js v18 or higher in your PATH
• An OpenAI API key OR active Codex CLI authentication
• If you do not have Codex CLI yet, the setup command in step 4 will offer to install it for you

Install (4 commands, run each inside Claude Code):

/plugin marketplace add openai/codex-plugin-cc

/plugin install codex@openai-codex

/reload-plugins

/codex:setup

Step 1 adds OpenAI's marketplace to Claude Code's plugin system. Step 2 installs the Codex plugin from that marketplace. Step 3 reloads Claude's plugin system so the new plugin is active. Step 4 runs the setup check and auto installs Codex CLI if it is missing.

Step 4 is the one people skip. The plugin will silently not work if Codex CLI is not installed and authenticated. Running /codex:setup verifies Node, npm, the Codex CLI install, and your auth all at once. If anything is missing, the setup command offers to install or fix it. Always run it before you try /codex:review for the first time.

Usage, the 3 commands you'll actually use:

/codex:review

Codex reviews the current diff inline in your Claude session.

/codex:rescue

Codex picks up a stuck task and tries again with different reasoning.

/codex:adversarial

Codex looks for what is wrong with Claude's solution (adversarial).

Why this workflow wins: you never leave the Claude Code session. Your context, your CLAUDE.md, your skills, your subagents all stay loaded. Codex becomes a tool inside Claude's workflow instead of a separate app you have to context switch into. Two models, one session, no friction.

Setup 2: Claude Code Inside Codex Desktop

If you prefer the Codex desktop app's GUI but still want Claude Code's speed for specific tasks, run Claude Code inside Codex's built in terminal. The Codex desktop app ships with an embedded terminal you can toggle with a single keyboard shortcut.

Prerequisites:

• Codex desktop app installed (download from openai.com/codex)
• Claude Code CLI installed and accessible via the claude command in your PATH
• Both tools authenticated separately (Codex via OpenAI account, Claude via Anthropic account)

Open the embedded terminal inside Codex:

# Inside the Codex desktop app, toggle the embedded terminal:
#   macOS:   Cmd + J
#   Windows: Ctrl + J
# The terminal panel opens inside the Codex window, scoped to
# your current project's directory.

# Then just launch Claude Code in that terminal:
claude

Both tools are now in the same workspace, sharing the same project directory, with their own auth and their own context.

Other useful Codex keyboard shortcuts: Cmd + B (or Ctrl + B) toggles the sidebar. Cmd + Option + B (or Ctrl + Alt + B) toggles the diff panel. Ctrl + L clears the embedded terminal. Source: OpenAI's official Codex app commands documentation at developers.openai.com/codex/app/commands.

When to use this direction: pick this setup if you prefer the desktop GUI for diff review, automations, and Git actions, but still want Claude Code's speed for one off scripts and personal software side projects. The Codex desktop app handles the visual side, Claude Code lives in the terminal panel for everything fast. Best of both, one window.

5 Hand Off Prompts

When you are mid session and need to hand off from one tool to the other, paste one of these. They preserve context cleanly so the receiving tool knows what has been tried and what is broken.

Hand off 1: Claude drafted, Codex reviews

Review the diff Claude Code just produced. Look for: edge cases, missing error
handling, type narrowness, and instructions I gave that Claude interpreted loosely.
Be adversarial. Assume Claude missed something.

Hand off 2: Codex stuck, Claude rescues

Codex has been stuck on this for 15 minutes. Take a fresh look. Don't keep going
down its current path. Re-read my original ask and propose a different approach.

Hand off 3: architecture then implementation

Claude Code: propose the architecture and write the plan in plan mode. Once
approved, hand the plan to Codex to implement file-by-file.

Hand off 4: pair programming mode

We're going to alternate. Claude Code writes the next change. Codex reviews. Claude
applies the review feedback. Codex reviews again. Repeat until clean. Tag each turn
so I can follow.

Hand off 5: the sanity check before ship

Before I ship this, do one final adversarial pass. Focus on: things that work in dev
but break in prod, race conditions, and anything that depends on my local
environment. Be brutal.

Plan Combo Recommendations

Which plans to actually pay for depends on your usage pattern.

• Light user (under 10 hrs/week of AI coding): Codex Plus $20 only. Claude Code's free tier handles the rest.
• Vibe coding operator (20 to 40 hrs/week): Claude Max $200 + Codex Plus $20. Claude is your daily driver, Codex is the reviewer.
• Production builder (40+ hrs/week shipping real product): Claude Max $200 + Codex Pro $100. GPT-5.5 Pro on Codex is worth the extra $80.
• Solo founder / agency owner: same as production builder, plus a second Claude account for parallel sessions on different projects.

Do not pay for both top tiers on day one. Start with whichever you already use, add the $20 plan of the other for 30 days. You will know in a week if the combination is actually shipping better work for you. If yes, upgrade. If no, downgrade the second tool. Way cheaper than guessing on $300 a month.

Go Deeper

Prefer a printable version? Grab the PDF: https://drive.google.com/file/d/10nOWPo1FUGmd6-fVFU7lhrz6-hU3AnZZ/view?usp=drivesdk

Want the whole system installed live, with Cooper on the call? Build Your Own AI, the two week sprint runs the first two weeks of August.

Or get a new working tool every Monday inside The AI Operator community on Whop.