Codex is OpenAI’s coding agent. It runs in the ChatGPT desktop app, as an open-source CLI, as an IDE extension, in the cloud and on iOS, and it can review pull requests on GitHub and take tasks from Slack and Linear.

It comes with ChatGPT plans rather than being sold on its own. Free and Go get a limited version in the desktop app, while Plus and up unlock the full set of surfaces and the GPT-6.1 models. The latest stable CLI is 0.169.0, released November 13, 2026.

Who it’s for

Anyone already paying for ChatGPT, and teams who want one agent that works locally, in the cloud and in code review. With an API key it also suits developers who’d rather pay per use than subscribe.

What stands out

  • Codex Cloud. Run tasks in the cloud in reusable environments, then review the results.
  • Code review. Tag @codex review on GitHub pull requests, local changes or, in beta, GitLab merge requests.
  • Hooks, subagents and skills. Run scripts at lifecycle events, configure custom subagents, and package reusable skills (custom prompts are deprecated in favour of skills).
  • Works where you do. Desktop app on macOS, Windows and Linux, the CLI, VS Code, Cursor and Windsurf extensions, Slack and Linear.
  • Mobile control. Start, approve and review tasks on a connected computer from your phone.

Drawbacks and things to watch

  • Limits vary a lot by model. The same plan gets many more messages on Luna than on Sol, so check which model you’re using.
  • Allowances may change in December. Press reports say ChatGPT and Codex usage will merge into one allowance on Plus, Pro and Business; OpenAI hasn’t published the size.
  • MCP server mode removed. codex mcp-server is gone; integrations must move to the experimental app-server protocol, which isn’t MCP.
  • Stricter in untrusted folders. Since 0.169.0, codex exec keeps project config and MCP servers disabled in untrusted directories unless you pass --trust.

Privacy and security

OpenAI says Business, Enterprise and Edu data isn’t used to train its models by default. Its help center describes individual plans as opt-out under Settings > Data controls; we couldn’t load that page directly, so check it yourself. Zero data retention is an API-only control. OpenAI reports SOC 2 Type 2 and ISO 27001 for its API platform and ChatGPT Enterprise.

Getting started

Install the CLI with curl -fsSL https://chatgpt.com/codex/install.sh | sh on macOS or Linux, or use npm install -g @openai/codex or brew install --cask codex. Then run codex and sign in with ChatGPT or an API key.

Plans and prices

Codex plans
PlanPriceWhat you get
Free$0GPT-6 Luna at standard speed in the desktop app, subject to rollout.
Go$8/moGPT-6 Luna at standard speed in the desktop app, subject to rollout.
Plus$20/moCodex on web, CLI, IDE extension and iOS. Cloud code review and Slack. GPT-6.1 Sol, GPT-6.1 Terra and GPT-6 Luna.
Pro$100, $200 or $500/moEverything in Plus, no five-hour limit. Ultrafast mode on Pro $500 only.
Business$20/user/mo annual, $25 monthly2+ users. Workspace credits with flexible pricing.
Enterprise & EduContact salesModels off until an admin enables them.
API keyPay per useCLI, SDK and IDE extension only; no cloud features such as GitHub review or Slack.

Codex FAQ

Is Codex free?

Partly. ChatGPT Free and Go include GPT-6 Luna at standard speed in the desktop app, subject to rollout. The CLI, IDE extension, cloud tasks, code review and the GPT-6.1 models need ChatGPT Plus ($20 a month) or higher.

How much does Codex cost?

It comes with ChatGPT plans: Plus is $20 a month, Pro $100, $200 or $500, and Business $20 per user billed annually ($25 monthly). You can also use the CLI and IDE extension with an API key at API rates, without cloud features.

What are Codex's usage limits?

They depend on the model. OpenAI estimates 15 to 160 local messages per five hours with GPT-6.1 Sol on Plus, 35 to 285 with Terra and 350 to 3,000 with Luna, plus a weekly limit. Pro plans currently have no five-hour limit.

Is the Codex CLI open source?

Yes. The Codex CLI is open source under Apache 2.0 on GitHub; the cloud service and desktop app aren't.

Does OpenAI train on my Codex code?

Business, Enterprise and Edu data isn't used for training by default. On individual plans, OpenAI's help center describes training as on by default with an opt-out under Settings > Data controls; Codex also has a separate setting for environments.

Latest changes

Nov 13, 2026releaseCodex CLI 0.169.0: codex exec no longer trusts project config without --trustNov 1, 2026limitsChatGPT and Codex will share one usage allowance from DecemberOct 29, 2026limitsPro plans get double the Codex allowance, and the Pro 200 cut is cancelledOct 26, 2026modelGPT-6.1 Terra arrives in Codex on paid ChatGPT plansOct 14, 2026modelGPT-5.5 retired from Codex for ChatGPT sign-inOct 8, 2026pricingGPT-6.1 Sol Ultrafast arrives in Codex, at 8x included usageSep 29, 2026modelGPT-6.1 Sol arrives in CodexSep 25, 2026securitymacOS desktop app 26.924 patches CVE-2026-100754

Sources

Facts last checked November 14, 2026.