Codex vs Gemini CLI: Which Terminal Agent Still Fits in Oct 2026?

Codex vs Gemini CLI, checked 19 Oct 2026: who can still sign in to Gemini CLI after the move to Antigravity CLI, Codex paid plans from $8, and which to pick.

Chaitanya Giri 4 min read Comparisons
Title card on white. The title Codex vs Gemini CLI in large ink type over a yellow underline, a Comparisons pill, a kicker reading Plans, limits, who can use each, a Checked 19 Oct 2026 line and a paper cup string telephone.

Codex vs Gemini CLI in Oct 2026: pick Codex unless you already pay Google for a Gemini API key, Vertex AI or a Code Assist licence. Gemini CLI stopped serving free, Google AI Pro and Ultra users on 18 Jun 2026, when Google moved them to Antigravity CLI. Both CLIs are Apache 2.0. Checked 19 Oct 2026.

Animation. A door marked Gemini CLI with a who can sign in list: paid Gemini API key, Vertex AI and Code Assist licence are ticked; free, Google AI Pro and Google AI Ultra are crossed out and move to an Antigravity CLI card dated 18 Jun 2026.
Who Gemini CLI still serves, from Google's notice and the Gemini CLI README on 19 Oct 2026.

If you want both agents at once rather than one, Munder Difflin is free and open source: a desktop app that runs a team of coding agents such as Claude Code, Codex and Gemini CLI on your own computer. More head to heads live in our Comparisons hub.

What are Codex and Gemini CLI?

Codex CLI is, in OpenAI’s README, “a coding agent from OpenAI that runs locally on your computer”. The same agent also comes as an IDE extension, a desktop app (codex app) and Codex Web. The README recommends you sign in with ChatGPT “to use Codex as part of your Plus, Pro, Business, Edu, or Enterprise plan”. Apache 2.0, 129,915 stars and release rust-v0.163.0 (15 Oct 2026) on 19 Oct 2026. See what is Codex.

Gemini CLI is, in Google’s README, “an open-source AI agent that brings the power of Gemini directly into your terminal”. The same README now opens with two notes: unpaid tier and Google One users were moved to Antigravity CLI on 18 Jun 2026, and Gemini CLI “has not been optimized for Gemini 4 Argon”. Apache 2.0, 107,454 stars and stable release v0.64.0 (13 Oct 2026) on 19 Oct 2026.

Codex vs Gemini CLI at a glance, checked 19 Oct 2026

Codex Gemini CLI
Licence Apache 2.0 Apache 2.0
Who can sign in ChatGPT Plus and up, or an OpenAI API key Paid Gemini API key, Vertex AI, Code Assist licences
Free use Free and Go list the desktop app only (19 Oct 2026) Ended 18 Jun 2026, per Google’s notice
First plan with the CLI Plus, $20 a month (19 Oct 2026) Pay as you go with an API key; prices vary
Models on the Plus card GPT-6.1 Sol and GPT-6 Luna on Plus Not optimised for Gemini 4 Argon, per its README
Other places IDE extension, desktop app, Codex Web, iOS IDE integration
Latest stable release rust-v0.163.0, 15 Oct 2026 v0.64.0, 13 Oct 2026

Sources: the Codex pricing page, the Codex README, the Gemini CLI README, Google’s transition notice and the Gemini CLI quota page, all read on 19 Oct 2026.

Who can still use Gemini CLI?

Google’s notice, posted on 19 May 2026, says: “On June 18, 2026, Gemini CLI will stop serving requests for Google AI Pro and Ultra, as well as those using it free of charge. These tiers are now supported via Antigravity CLI.”

What remains is paid and work access. Google’s quota page, last updated on 18 Jun 2026, lists a pay as you go Gemini API key, Vertex AI, and Gemini Code Assist Standard and Enterprise at 1,500 and 2,000 requests per user a day. That page still lists the old free tiers in its body, so treat the notice and the banner above it as the newer word. Our Gemini CLI vs Claude Code page covers the move in more detail, and Claude Code vs Antigravity covers where Google sends you instead.

What does Codex cost?

The CLI is free to install; you pay through a ChatGPT plan or an OpenAI API key.

Animation. A tiered cake of Codex plans: Free $0, Go $8, Plus $20 with a flag that reads CLI starts here, and Pro from $100, beside a slice for Business at $20 per user.
Codex plans from OpenAI's Codex pricing page on 19 Oct 2026. Tap a tier to see what it adds.

OpenAI’s Codex pricing page lists these plans on 19 Oct 2026:

  • Free, $0, and Go, $8 a month: GPT-6 Luna at Standard speed in the desktop app, “subject to rollout”.
  • Plus, $20 a month: Codex on the web, in the CLI, in the IDE extension and on iOS, with GPT-6.1 Sol and GPT-6 Luna.
  • Pro, from $100 a month: plans at $100, $200 or $500, with Ultrafast mode on Pro $500.
  • Business, $20 per user a month: billed annually for 2 or more users, or $25 billed monthly.
  • API key: Codex in the CLI, SDK or IDE extension, paid at API prices, with no cloud features.

See Codex pricing for the plan details.

Where does each one run?

Both run in the terminal; Codex reaches more places beyond it.

Animation. Two pots, Codex and Gemini CLI, grow labelled sprouts: Codex runs in the terminal, IDE extension, desktop app and web; Gemini CLI runs in the terminal, IDE integration and headless mode.
Where each one runs, from each README on 19 Oct 2026.
  • Codex runs in the terminal, in VS Code, Cursor and Windsurf through its IDE extension, as a desktop app and on the web. Release rust-v0.163.0 lets you send a follow up “while Codex is responding to steer it immediately”.
  • Gemini CLI runs in the terminal, with IDE integration and a headless mode for scripts. Its docs list subagents, hooks, plan mode and MCP servers.

Which should you pick?

Pick by the account you already pay for.

  • Pick Codex if you have a ChatGPT plan, or want one: Plus at $20 is the first plan with the CLI (19 Oct 2026).
  • Pick Munder Difflin if you want both at once: a free and open source desktop app that runs a team of coding agents such as Claude Code, Codex and Gemini CLI on your own computer.
  • Pick Gemini CLI if your company already buys Gemini Code Assist or Vertex AI, or you pay for a Gemini API key.
  • Pick Antigravity CLI if you are on a free Google account or Google AI Pro or Ultra: that is where Google moved you.

Want Codex and Gemini CLI working on one job side by side? See best Claude Code multi agent tools, or start with the Munder Difflin install guide.

FAQ

Is Codex better than Gemini CLI?

Unless you pay Google for API or work access, Codex is the one you can start with in Oct 2026: it comes with ChatGPT plans, and its CLI is listed from Plus at $20 a month. Gemini CLI now serves paid API keys, Vertex AI and work licences; free, Google AI Pro and Ultra users were moved to Antigravity CLI on 18 Jun 2026.

Is Gemini CLI still free?

No. Google's notice says that on 18 Jun 2026 Gemini CLI stopped serving requests for Google AI Pro and Ultra and for people using it free of charge, and that those tiers are now supported via Antigravity CLI.

Can I use Gemini 4 Argon in Gemini CLI?

Google advises against it. The Gemini CLI README says it "has not been optimized for Gemini 4 Argon" and points you to Antigravity instead. Checked 19 Oct 2026.

How much does Codex cost?

OpenAI's Codex pricing page on 19 Oct 2026 lists Free at $0, Go at $8 a month, Plus at $20, Pro from $100 and Business at $20 per user a month billed annually for 2 or more users. Plus is the first plan that lists the CLI and the IDE extension. You can also sign in with an API key and pay API prices.

Are Codex and Gemini CLI open source?

Yes. Both repos are Apache 2.0 according to the GitHub API on 19 Oct 2026.