Mobile: iPhone and Android

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What you will accomplish

The phone sends prompts, replies and approvals. The connected host supplies files, terminals, browsers and tools. Seeing a task on your phone does not mean its project has been downloaded to the phone or that it keeps running after the computer shuts down. Learn to identify the working location before requesting extensive edits remotely.

Prepare both devices

Complete desktop setup on the computer. Extract the todo materials, copy expected into codex-practice and open that project on the computer. Confirm all five files exist. This lesson does not require GitHub or a separate SSH server.

On iPhone, install or update OpenAI's ChatGPT app from the App Store; on Android, use Google Play. Both devices must use the same ChatGPT account and workspace with Codex access. An organization may need to enable Remote Control, and authentication can require SSO, multi-factor verification or a passkey. Complete those requirements instead of creating more tasks to work around them.

As of 2026-09-14, the Remote documentation lists iOS and Android as mobile entry points and the Mac and Windows desktop apps as hosts. Availability varies by rollout. Do not infer that the Linux desktop preview supports this mobile-host workflow. The CLI or IDE extension cannot replace the desktop app for initial pairing.

Mark this particular copy

On the computer, create remote-check.txt in the codex-practice root with a plain-text editor. This is an extra identification file, not one of the five website source files. Read an existing file first rather than overwriting another task's data. Write the line below, replacing the final 01 with a code you choose before saving. Give different copies different codes; do not use account details, passwords or pairing codes.

REMOTE-PRACTICE-01

Record the code, host name and full folder path in your own notes. Do not include the code in the later prompt: have Codex read it from the file. This helps distinguish a generic answer from access to this copy; also inspect the tool record.

Stage 1: enable the connection on the computer

On the computer that will do the work, open the ChatGPT desktop app and go to Settings → Connections → Control this Mac or PC. Select Set up or Add, enable remote access and complete verification. Check the computer name and project so you do not pair an empty test machine and then search for missing materials.

The app displays a QR code to pair the phone with this host. Scan it with your own phone; do not include it in public tutorial screenshots or send it to other people. Each host needs pairing. Signing into the same account does not establish that every device is already connected.

In Connections, check whether other devices can connect and inspect any keep-awake options. The host needs the app open, an internet connection and an awake session. Start with a Mac laptop plugged in and its lid open. On Windows, Computer Use has additional desktop-availability requirements. This exercise only reads files, so enabling every computer-control feature is unnecessary.

Stage 2: complete pairing on the phone

On iPhone, scan the host's QR code with the camera, open the link in ChatGPT and follow Remote setup, checking the account and workspace. If the link stays in a browser, confirm the latest app is installed, then restart pairing on the host. A web conversation history is not the Remote connection success screen.

On Android, scan the QR code, choose ChatGPT to open it, and complete account and workspace verification. If Android asks which app should handle the link, choose the official ChatGPT app. If Remote is missing, update and reopen the app, then check feature availability. A different mobile browser cannot guarantee access to a feature that has not rolled out.

Success is the same on both systems: Remote shows the host, you can select it, and its projects or tasks are visible. Notifications can announce completion or attention requests, but return to the task to inspect the actual result. A notification alone is not file verification.

Stage 3: complete a read-only task

In Remote, select the newly paired host and open a Codex task in codex-practice. If creating a new task, confirm its location is still the practice folder on the host. Paste the following into the mobile task composer, not a phone search box as a shell command.

Read this practice project without changing files.
Report the host or environment name if available and the current working folder.
List index.html, style.css, app.js, core.mjs and core.test.mjs.
Explain how task completion is stored and name the localStorage key.
If you cannot inspect a file, report the limitation instead of guessing.

Expect the practice path, the dedicated mokaair-codex-todo-v1 storage key and an explanation of the completed field based on the source. Back at the computer, inspect app.js and core.mjs and confirm no files changed. General advice about todo sites without a path or source evidence does not complete the exercise.

Send a follow-up asking why a whitespace-only task is rejected, with a specific file reference. This checks that you continued the same task and context. Node.js does not need to be installed on the phone: local tools come from the host. Before a later exercise runs tests, confirm that host actually has the required runtime.

In the same project, explain what happens when the new task contains only spaces.
Identify the relevant function and file. Do not edit or reset stored data.

Expect an explanation of addTask in core.mjs trimming and rejecting blank text, together with form error feedback. You can try blank input in the computer's preview. The normal case is reading the project successfully; the boundary case is rejected whitespace. Both need evidence you can compare.

Check the host and current file again

Read remote-check.txt from this task's working folder and quote its one-line content.
Report the absolute file path and the tool used to read it.
Do not edit files. If the file cannot be read, stop and report that limitation.

Compare the returned code and path with your computer-side notes, then inspect the file-read record. A wrong code, missing file or guessed answer means you should stop further edits and check the selected Remote host and task. Correct the location and read the same file again; do not “fix the answer” by telling Codex the code. If no tool record is available, leave that check unverified. Afterwards, remove only the remote-check.txt you created and keep the website sources.

Understand interruptions

After the read-only work finishes, you may briefly disconnect the host and observe the phone's unavailable state. Do not deliberately test disconnection during writes. Restore the connection, open the desktop app and return to the original task. An offline message establishes current unreachability, not that the previous operation never happened.

After reconnecting, inspect the last response and files before resubmitting. Repeating a create, delete or submit request can duplicate its effects. This exercise uses read-only requests to teach status interpretation before moving on to writes.

Remote, cloud work and phone URLs

Remote uses the connected host's project and tools. Cloud tasks use a separately configured environment. Their files, branches and dependencies may differ; similar task names do not establish that they are the same work. Opening a website on a phone also does not grant access to a computer's local project.

In http://127.0.0.1:4173 on the computer, 127.0.0.1 refers to that computer. Entering the same address in the phone's browser points to the phone itself. For results, inspect previews or screenshots supplied by the host in the Remote task. This exercise does not require opening a public network port.

Troubleshooting and disconnecting

Missing host: check the desktop app is running, connections are allowed, both account and workspace match, and the computer is awake. Fix the actual condition before pairing again. For an old unused pairing, follow the official update and re-pair guidance.

No pairing request: open Remote on the phone, then restart setup from the host. For an organization account, confirm that the administrator enabled Remote Control. Completing sign-in does not establish policy permission. Keep useful error details for the administrator without including verification codes.

Connected but missing files: check the host name and working folder, then whether the project exists on that machine. A similarly named folder on another computer does not automatically synchronize. Moving tasks between environments involves real environment and Git state; beginners should finish verification on the original host first.

When finished, use Settings → Connections on the host to disable remote control or remove an unused pairing. Confirm the phone can no longer operate the host. Disabling Remote does not undo file changes or guarantee that all work has stopped. Stop any running task within the task itself and check its state first.

Practice and verification record

From the phone, request a handoff note containing the working location, file list and checks not run. Return to the same task on the computer. Success means both views identify the same host and path, and you can distinguish inspected results from suggested future checks.

Entry points, pairing and host requirements were checked against Remote connections on 2026-09-14. This lesson has not been tested on physical iPhone/Android devices or through an actual pairing; its diagram explains relationships. Practice-site behavior has separate browser verification. Continue with context handoff, permissions and cloud work.

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Phone to Mac / Windows to Files

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