Codex Mobile Remote: allow downloading generated workspace files to the phone

Start with the Remote Connections and Work with Files documentation to verify the current mobile workflow, then review related issues #25202 and #29125. Done should provide authenticated retrieval of arbitrary host-generated files from iOS and Android, with preview, download, sharing, progress, and actionable transfer errors.

What variant of Codex are you using?

ChatGPT mobile app / Codex Remote connected to a Codex App host. The request applies to iOS and Android clients with macOS or Windows hosts.

What feature would you like to see?

Please add a first-class way to download or export files produced by a remote Codex task directly from the mobile app.

A common workflow is:

1. Start or supervise a Codex task from the phone.
2. Codex creates an output such as a DOCX, XLSX, PPTX, PDF, ZIP archive, image, dataset, or another workspace file on the connected host.
3. The task reports a host-local file path, and the file may also appear in the workspace file browser.
4. The mobile user cannot retrieve that file without returning to the host or manually uploading it somewhere else.

Requested behavior:

• Generated-file cards and files selected in the workspace browser should expose clear Preview, Download, and Share actions.
• On iOS, downloading should support the share sheet and Save to Files.
• On Android, downloading should support the system share sheet and Downloads/document picker.
• Formats that cannot be previewed should still be downloadable as binary files.
• Preserve the original filename, extension, MIME type, and byte size.
• Show transfer progress and actionable errors when the host is offline, a policy blocks transfer, or the file exceeds a limit.
• Use an authenticated, short-lived relay or equivalent secure transfer mechanism rather than exposing host-local paths.
• Optionally allow selecting several outputs and downloading them as a ZIP archive.

If this is already supported, please document the exact mobile workflow and surface the action more clearly in the UI.

Additional information

The Remote Connections documentation says mobile users can review outputs and that iOS includes a workspace file browser, but it does not describe how to save a host-generated workspace file to the phone. The Work with Files documentation explicitly describes downloading generated files on the web, not from a Mobile Remote session:

• https://learn.chatgpt.com/docs/remote-connections
• https://learn.chatgpt.com/docs/artifacts-viewer

Related issues:

• openai/codex#25202 covers media artifacts that do not render in Mobile Remote.
• openai/codex#29125 requests remote previews for video and PDF artifacts.

This request is broader and specifically about reliable retrieval/export of arbitrary generated files from the mobile client, independent of whether the format has an inline preview.