OpenAI Codex: What It Is and When to Use It

Codex is OpenAI's AI coding agent: the same idea as Claude Code, powered by OpenAI's models. You tell it what to build in plain English; it writes and runs the code. It comes as a command-line tool, a web/cloud version, and IDE integrations.

Why you should know about it (even if you use Claude Code)

Two reasons:

1. Second opinions are free leverage. On the show, we sometimes have Codex review what Claude Code built, or vice versa. Two different AI "engineers" catching each other's mistakes is one of the easiest quality upgrades in vibe coding.
2. Cloud tasks. Codex can run jobs in the cloud. You hand it a task, close your laptop, and check the result later.

Getting started

1. Codex is included with ChatGPT Plus and Pro subscriptions. If you already pay for ChatGPT, you already have it.
2. Install it from openai.com/codex (the CLI installs with one command; there are also IDE extensions).
3. Same rules as Claude Code: describe the outcome, start small, ask it to verify its own work.

Codex vs. Claude Code, honestly

• Both can build real, complete software from plain-English instructions. A beginner will feel the workflow differences more than the model differences.
• Claude Code is generally the stronger fit for long, multi-step builds where the agent works independently for a while, which is why it's our main tool on air.
• Codex is a great second seat: reviews, parallel tasks, cloud jobs, and it's effectively free if you already have ChatGPT.
• The real answer: the tools leapfrog each other every few months. The skill that lasts is knowing how to direct them. That transfers across every tool, and it's the whole point of this show.

Watch it in action

When we run head-to-head builds or AI-reviews-AI segments on the show, they land on the replays page with the full prompts.