Codex from your Android phone

The Codex CLI runs in a terminal on your own machine. Start it on a server inside tmux or Herdr and Termexa lets you check its progress, review the changes and approve the next step from Android.

Termexa is an independent SSH client. It is not made by, affiliated with or endorsed by Anthropic or OpenAI. Claude Code and Codex are their respective owners' products and run on your own machine with your own account; Termexa only carries the terminal to your phone.

The problem

An agent working through a long task needs an approval or a decision while you are away.
Reviewing what it changed means reading diffs on a phone-sized screen.
Typing slash commands and file mentions on a phone keyboard is slow.

Set it up

Run Codex inside tmux or Herdr on the server. Save tmux new -A -s codex as the host's command to run and start codex in it, so it keeps going when the phone disconnects. See tmux on Android.
Pick an approval mode before you leave. The /approvals key types the command that chooses how much Codex may do without asking.
Get told when to look. With Terminal alerts on, Termexa notifies you when a terminal you are not looking at rings its bell, disconnects, or finishes a long command. In Herdr, panes waiting for input are marked Needs input.
Answer and steer. Use the arrows, Enter and Esc on the toolbar, Ctrl+J for a new line, voice input for longer instructions, and scheduled messages to send the next task later.

Illustration of the flow: a notification, the pane that needs input, then the prompt. Drawn from the app's layout; not a screenshot.

Review the work from your phone

/diff shows the changes in the working tree, and /review asks for a code review.
/mention picks a file to bring into the conversation; /mcp shows MCP server status; /new starts a fresh conversation.
Open the host's file window to read changed files in the text editor or preview Markdown, or open a second terminal on the same host for git log and tests.
Text Codex prints can be copied to the phone clipboard over OSC 52, after you allow it for that host.

Commands available as keys

Shared with Claude Code: /compact, /model, /status, /review, /init. Codex only: /new, /diff, /approvals, /mention, /mcp. Each key types the command and leaves Enter to you.

Frequently asked questions

Does Codex run on the phone?

No. The Codex CLI runs on your server or computer. Termexa is the SSH terminal you use to reach it from Android.

Is Termexa made by OpenAI?

No. Termexa is an independent SSH client and is not affiliated with OpenAI.

Can I review Codex's changes on a phone?

Yes. Use /diff and /review in Codex, read files in Termexa's SFTP file window, or run git commands in a second terminal on the same host.

Does Termexa store my OpenAI credentials?

No. Codex signs in on your server. Termexa only stores the SSH credentials for your hosts, encrypted on the phone.

Do the agent keys send the command right away?

No. They type the slash command and leave Enter to you, so you can check or edit it before sending.