[Bug] Dragging a file onto the Claude Code tab opens it as an editor tab instead of attaching it to the session

[tbarsness]

Problem to solve

Dragging a file onto the Claude Code tab does not attach it to the Claude session. Instead, VS Code's editor drop handler intercepts the drop and opens the file as a new editor tab in the same editor group, next to the Claude Code tab. Claude never becomes aware of the file.

For images this is doubly confusing, because the opened tab often fails to render ("An error occurred while loading the image"), so it looks like the drop failed entirely rather than having been misrouted.

Steps to reproduce

1. Open a workspace and focus the Claude Code tab.
2. Drag any file from Finder onto the Claude Code view.
3. Observe: a new editor tab opens for that file. Nothing is added to the Claude session.

Expected

The dropped file's path is inserted into the Claude Code prompt (or the file is attached to the session), the way it works in Claude Code running in a plain terminal.

Notes on cause

The Claude Code view is a webview served from Contents/Resources/ide-views/terminal/. Grepping the shipped bundle (main.a38e6cdb08224913.js) for file-drop APIs returns nothing:

• onDrop / ondrop: 0 occurrences
• getAsFile: 0 occurrences
• webkitGetAsEntry: 0 occurrences

The only dragover / dragenter / dragleave / drop strings in the bundle belong to React's synthetic event registry, not to any application handler. So the webview registers no drop target, the drag falls through to the surrounding VS Code editor group, and the workbench's default "open dropped file" behavior wins.

A dragover handler that calls preventDefault() plus a drop handler that reads dataTransfer.files and writes the resulting path(s) into the terminal input should be enough to claim the drop before the workbench sees it.

Workarounds that do not work

Holding Option while dragging (the usual macOS "paste path instead of file" modifier) does not help. The editor drop handler still wins.

The only working workaround is typing or pasting the absolute path into the prompt by hand.

Related

This is the drag-and-drop sibling of #6 (copy-paste image support). Same underlying gap: the terminal webview has no path for ingesting a file from the host, whether by paste or by drop. Fixing them together would likely share most of the work.

Environment

• DevSwarm 2.4.0 (com.twentyfirstidea.devswarm)
• macOS, Darwin 25.5.0

[trevordilley]

@tbarsness So! Something we discovered is that if you hold shift VS Code will accept the drop. We've been trying to figure out a way to enable drag and drop support for this, and one of our devs randomly mentioned "If you just hold shift VS Code accepts drag/drop fine?"

We'll think about finding a way to surface this better, cause it definitely helped me!