Let the agent hand files to the user: attach to its own reply, drag out of chat, preview .docx/.pdf

[feechkablum6]

Before submitting

• I searched existing issues and discussions and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

apps/desktop (chat attachments and file preview)

Problem or use case

A lot of my agent work ends with a file for someone else, for example a .docx instruction for a client. The agent creates it, and then I need to put it into another app, usually by dragging it into an upload field in the browser. Today there is no good way for the agent to hand me that file in the chat.

1. Files from the agent show up as my own messages. The only way I found is t3_attachment_prepare_upload plus t3_thread_send_attachments. The file lands as a right-aligned user-side message labeled "Sent by another agent" with a Steer button, so it looks like I sent the file to myself. Sending it also starts a new run in the same thread, and the agent then replies to its own attachment.
2. Attachments can't be dragged out of the chat. The chip has a preview (eye) button and a download button. It can't be dragged into Finder or into a browser upload field, so I have to download it and then look for the file again.
3. No preview for .docx. The eye button shows "No preview for this file. Save it to open in an app that supports docx files." To check the document before sending it, I had the agent render the pages to PNG and send them as two more user-side attachments.

Proposal

1. Let the agent attach a file to its own reply. For example, a Markdown link to a local file path could render as a file card in the assistant message, the same way image paths already render inline. No new user message and no new run.
2. Make attachment chips and file cards draggable to the OS (Electron webContents.startDrag), so a file can be dropped straight into Finder or a browser upload field.
3. Preview for common document types, at least .docx and .pdf. A simple read-only render is enough to check the content before sending it on.

Related

#6894 asks for Reveal in Finder / Download in the Files panel. That is about reaching workspace files. This one is about the agent handing a finished file to the user inside the conversation.

T3 Code Nightly 0.0.46-nightly.20261007.2761, macOS, Claude provider.