---
{"title": "Codex CLI vs Gemini CLI in 2026", "description": "Codex CLI and Gemini CLI compared on what each terminal tool does and what to check before you pick, plus what AgentHydra adds for managing sessions.", "url": "https://supakeeper.com/codex-cli-vs-gemini-cli/", "date": "2026-10-26"}
---
Codex CLI and Gemini CLI compared on what each terminal tool does and what to check before you pick, plus what AgentHydra adds for managing sessions.

Codex CLI is a terminal tool whose /init command creates an AGENTS.md file with instructions for Codex [^1], whose /review command reviews changes and finds issues [^1], and whose /status command shows the current session configuration [^1]. Gemini CLI publishes nightly releases daily at 00:00 UTC [^2], installs on macOS through MacPorts [^2], and, for unpaid tier and Google One users, was replaced by Antigravity CLI on June 18th, 2026 [^2]. AgentHydra shows the Claude Code, Codex and OpenCode sessions on your machine in one searchable list, updated live while they run [^3]. The two tools answer different needs: Codex CLI sets up instructions and checks work inside the terminal, while Gemini CLI keeps to a steady release schedule and hands unpaid and Google One users to Antigravity. AgentHydra sits on top of them, listing the agent sessions that these tools start.

| Option | What its sources say it does | Cost | Account or install |
|---|---|---|---|
| Codex CLI | Lets users inspect code, make changes, run commands, and automate repeatable work without leaving the terminal [^1]; /init creates an AGENTS.md file with instructions for Codex [^1]; /review reviews changes and finds issues [^1]; /status shows the current session configuration [^1] | not published | Installed with the standalone installer for macOS and Linux [^1]; on first run, choose Sign in with ChatGPT or another available sign-in method [^1] |
| Gemini CLI | An open-source AI agent that brings the power of Gemini directly into your terminal [^2]; provides lightweight access to Gemini [^2]; can query and edit large codebases [^2]; replaced by Antigravity CLI on June 18th, 2026 for unpaid tier and Google One users [^2] | not published | Install globally with npm [^2], via Homebrew on macOS and Linux [^2], via MacPorts on macOS [^2], or run with no installation via npx [^2] |
| AgentHydra | Shows Claude Code, Codex and OpenCode sessions on your machine in one searchable list, updated live while they run [^3]; lets you type a reply into a Claude session's desktop chat or send one message to several sessions [^3]; splits a task's pieces across Claude Code CLI sessions and moves a worker to another account when one nears its limit [^3]; shows cost at API list prices by day, model, project and account [^3] | Free, no account or subscription [^3] | On Windows, install with a one-line PowerShell script, or download a build from GitHub Releases or run from source with Bun [^3]; the tray app needs Windows, macOS and Linux builds exist but have not been verified [^3] |

## The short answer

Codex CLI is a terminal tool whose /init command creates an AGENTS.md file with instructions for Codex [^1], whose /review command reviews changes and finds issues [^1], and whose /status command shows the current session configuration [^1]. Gemini CLI publishes nightly releases daily at 00:00 UTC [^2], installs on macOS through MacPorts [^2], and, for unpaid tier and Google One users, was replaced by Antigravity CLI on June 18th, 2026 [^2]. AgentHydra shows the Claude Code, Codex and OpenCode sessions on your machine in one searchable list, updated live while they run [^3]. Each source points to a different need. Codex CLI's page frames commands for setting instructions, checking work and viewing the session state [^1] [^1] [^1]. Gemini CLI's page frames a steady release cadence and a hand-off to Antigravity for some users [^2] [^2]. AgentHydra's claims frame watching and driving the sessions that are already running on your accounts [^3].

## What Codex CLI, Gemini CLI is built for

Codex CLI's own page describes commands for working inside the terminal. Its /init command creates an AGENTS.md file with instructions for Codex [^1]. Its /review command reviews changes and finds issues [^1]. Its /status command shows the current session configuration [^1]. Those three commands set up how Codex should work, check the work it has done, and show what the session is set to, all without leaving the terminal [^1] [^1] [^1]. Gemini CLI's own page describes its release and distribution pattern. Nightly releases are published daily at 00:00 UTC [^2]. It can be installed on macOS with MacPorts [^2]. For unpaid tier and Google One users, Gemini CLI was replaced by Antigravity CLI on June 18th, 2026 [^2]. The page describes more of what each tool does; those descriptions appear in the table below.

## What AgentHydra is built for

AgentHydra is made by the team that publishes this site. It shows the Claude Code, Codex and OpenCode sessions on your machine in one searchable list, updated live while they run [^3]. It lets you type a reply into a Claude session's own desktop chat, or send one message to several sessions [^3]. It moves a Claude chat, history included, to another of your accounts [^3]. It splits a task's pieces across Claude Code CLI sessions on your accounts, and moves a worker to another account when one nears its limit [^3]. It shows cost at API list prices by day, model, project and account [^3]. It pairs each failed shell command with the command that fixed it, and can copy those pairs out as a rules file for your agents [^3]. It lists each Claude and Codex account with its plan and 5-hour and weekly quota, and can open, focus, quit, create and delete Claude Desktop instances [^3]. It exposes its features as MCP tools, including whoami and usage checks so an agent knows which account it is on and how much quota is left [^3]. It packs a task and its repository into a Markdown file, leaving out common secret files, then copies a prompt and opens ChatGPT for you to send yourself [^3]. It prints the same cost numbers as JSON from the command line [^3].

## Pricing and fees

The facts here state no dollar price for Codex CLI, so none is published here [^1]. The facts here state no dollar price for Gemini CLI either, so none is published here [^2]. AgentHydra is free, with no account or subscription [^3]. Neither rival fact states an account, trial, discount or paid tier, so none is stated here for them. The only price given in the facts for any tool here is free for AgentHydra [^3]. If you need the cost of Codex CLI or Gemini CLI for your own use, check their own pages, since the facts here do not state one.

## Setting it up and daily use

Codex CLI's page says it installs with the standalone installer for macOS and Linux [^1], and on first run it offers Sign in with ChatGPT or another available sign-in method [^1]. It can be used interactively or called via codex exec from repeatable workflows and pipelines [^1]. codex resume reopens a recent chat from the current repository or searches across local chats for older work [^1]. Gemini CLI's page describes several install paths: global install via npm [^2], Homebrew on macOS and Linux [^2], MacPorts on macOS [^2], or running with no installation via npx [^2]. For AgentHydra, on Windows you install with a one-line PowerShell script, or download a build from GitHub Releases or run from source with Bun [^3]. The tray app needs Windows; macOS and Linux builds exist but have not been verified [^3]. The facts here say nothing more about day to day use of the rivals, so check their own pages for anything further.

## Things to check before you choose

Ask which tool fits the way you work. Codex CLI's commands set up instructions, review changes and show the session state [^1] [^1] [^1]. Gemini CLI's releases run on a fixed daily and weekly schedule, with Antigravity replacing it for some users [^2] [^2]. Ask whether Gemini CLI is still the tool you will get. Its page says unpaid tier and Google One users moved to Antigravity CLI on June 18th, 2026, so check where your account stands [^2]. Ask whether you want a place to see the sessions these tools start. AgentHydra lists Claude Code, Codex and OpenCode sessions in one searchable list, updated live [^3]. Ask what data leaves your machine, since the facts here say nothing about that for any of the tools.

## How to choose

Match the need to the tool whose source says it meets it. If you want to set an instructions file for a terminal agent, Codex CLI's /init command creates an AGENTS.md file [^1]. If you want a fixed release schedule, Gemini CLI publishes nightly releases daily at 00:00 UTC [^2]. If you are an unpaid tier or Google One user, decide whether you want the tool that replaced Gemini CLI on June 18th, 2026 [^2]. If you want one list of the Claude Code, Codex and OpenCode sessions on your machine, updated while they run, AgentHydra provides that [^3]. If you want to send a reply into a Claude session's desktop chat or to several sessions at once, AgentHydra does that [^3]. If you want cost at API list prices by day, model, project and account, AgentHydra shows that [^3].

## Frequently asked questions

### Is AgentHydra free to use?

AgentHydra is free, with no account or subscription [^3]. It is open source under the MIT License [^3]. On Windows, it installs with a one-line PowerShell script, or you download a build from GitHub Releases or run from source with Bun [^3]. The facts here give no other price for AgentHydra.

### Does Codex CLI cost anything?

The facts given here do not state a dollar price for Codex CLI [^1]. Its page describes commands for installing, signing in and working, but the facts here say nothing about a fee. Check its own pages if you need the cost.

### Does Gemini CLI cost anything?

The facts given here do not state a dollar price for Gemini CLI [^2]. Its page describes install paths and its release schedule, but the facts here say nothing about a fee. Its page does say that for unpaid tier and Google One users it was replaced by Antigravity CLI on June 18th, 2026 [^2].

### Can AgentHydra list the sessions that Codex CLI and Gemini CLI start?

AgentHydra shows the Claude Code, Codex and OpenCode sessions on your machine in one searchable list, updated live while they run [^3]. The facts given here do not say whether AgentHydra lists Gemini sessions, so check its own pages for that. It also shows cost at API list prices by day, model, project and account [^3].

### What happened to Gemini CLI in 2026?

For unpaid tier and Google One users, Gemini CLI was replaced by Antigravity CLI on June 18th, 2026 [^2]. Nightly releases for Gemini CLI are published daily at 00:00 UTC [^2]. Check which release channel and tier you are on, since the facts here do not say whether the replacement applies to paid users.

Free, with no account or subscription. [^3] - [Visit AgentHydra](/go/start)

## Sources

[^1]: Codex CLI, developers.openai.com/codex/cli, read 2026-10-18 (https://developers.openai.com/codex/cli)
[^2]: Gemini CLI, github.com/google-gemini/gemini-cli, read 2026-10-18 (https://github.com/google-gemini/gemini-cli)
[^3]: AgentHydra's own description of itself (the product of this site's publisher) (/go/start)