Set Up Codex Mobile

This tutorial connects a computer running the Codex App to the ChatGPT mobile app, then verifies the connection with a read-only task.

Completed State

ChatGPT mobile app (iOS / Android)
          |
          | secure remote connection
          v
Codex App host (macOS / Windows)
          |
          +-- project files
          +-- shell and tests
          +-- plugins and permissions

The setup is complete when the phone can select a host project, start a thread, and display results.

Check Prerequisites

• A ChatGPT account with Codex access
• The latest ChatGPT mobile app
• The latest Codex App for macOS or Windows
• The same account and workspace on both devices
• Remote Control enabled by an administrator when required
• Access to required MFA, SSO, or passkey steps

OpenAI’s documentation states that mobile setup starts in the Codex App, not in Codex CLI or the IDE extension.

Step 1: Prepare the Host

Open the project in the Codex App and check the Git working tree.

git status --short

Expected output:

# No output when the working tree is clean

Check: Confirm the project name, path, and any existing changes before continuing.

Step 2: Start Codex Mobile Setup

Select Set up Codex mobile in the Codex App sidebar. Enabling remote access displays a QR code.

Check: A pairing QR code is visible on the host.

Step 3: Scan the QR Code

Scan the code with the phone. When ChatGPT opens, confirm the same account and workspace, then complete any MFA, SSO, or passkey step.

Check: The host name appears in the Codex area of the ChatGPT mobile app.

Step 4: Review Connection Settings

Open Settings > Connections in the Codex App and confirm:

• The expected phone is registered
• No unknown device is registered
• Keep-awake behavior matches the intended use
• Computer Use and the Chrome extension are enabled only when needed

Check: The connected devices and enabled capabilities can be explained clearly.

Step 5: Verify with a Read-Only Task

Inspect this project and report its project type, main article directory,
and verification commands. Do not change files. List the files used as evidence.

Expected result:

- Project type
- Article directory
- Verification commands found in package.json or repository docs
- Confirmation that no files changed

Check: The report matches the host project and no new diff appears.

Step 6: Test an Approval

Run `git status --short` and report the output.
Do not write files or access the network.

If an approval appears, verify that the command matches the request before approving it.

Check: The phone shows the command and its output.

Troubleshooting

Symptom	Check
Host is missing	Codex App is running, remote access is enabled, and accounts match
Approval is missing	Open the Codex mobile view and check notifications and workspace
Session disconnects	Check host sleep, network, and Codex App state
Authentication blocks setup	Complete MFA, SSO, or passkey steps and check admin policy
Codex menu is missing	Update both apps and check rollout and region support

Disconnect a Device

If a phone is lost or a shared device was used, remove it from Settings > Connections on the host. Review account sessions, MFA, and workspace policy when appropriate.

Summary

The host remains the execution environment after pairing. Start with read-only work, inspect connected devices and capabilities, and only then move to write operations.

Next, Run a Practical Development Task applies the connection to a complete workflow.

See the references for the external specifications and background sources used on this page.[1][2]

References

1. OpenAI, Codex documentation
2. OpenAI, OpenAI API documentation