[Feature Request] Attach files to messages on iOS #6251

Description

Add support for attaching files to messages in the T3 Code iOS app, similar to the file attachment experience in the Claude and ChatGPT mobile apps.

Currently, the mobile app allows attaching photos, but there is no option to select and attach arbitrary files from the iOS Files app.

Proposed UX

Add a “Files” option to the existing attachment menu.

Tapping it should open the native iOS file picker and allow the user to select one or multiple files and attach them to the current message.

For example:

+ → Files → select file(s) → Send

The attached files should be available to the coding agent as part of the message/context, just like attachments in Claude Mobile and ChatGPT for iOS.

File types

Ideally support common file types such as:

• PDF
• Markdown (.md)
• Text (.txt)
• CSV
• JSON
• Office documents
• Images
• Other file types supported by the underlying agent/provider

Use cases

This would make it possible to send an agent things like:

• specifications and requirements
• PDFs and documentation
• logs
• configuration files
• datasets
• code files
• documents received through email, Telegram, Slack, etc.

without first having to manually transfer them to the remote machine.

Expected behavior

The experience should be similar to attaching a file in Claude Mobile or ChatGPT for iOS:

1. Tap the attachment button.
2. Select Files.
3. Choose one or more files using the native iOS picker.
4. Files appear as attachments above the message composer.
5. Send the message together with the attachments.

Related issues

Related, but not duplicates:

• [Bug]: Cannot attach or paste images in remote web session on mobile Chrome #2803 — attachment/file-picker support for images in a mobile web session.
• [Feature]: Upload picture from phone (web app) ? #2853 — uploading pictures from a phone in the web app.
• [Feature]: Video preview #5166 — previewing video/media files produced by the agent, including on mobile.

This request is specifically about user-selected arbitrary files from the native iOS Files picker being attached to a message in the T3 Code iOS app, similar to Claude Mobile and ChatGPT for iOS.