Hey, this is a known limitation. Dev Containers aren’t supported in the Agents Window in Glass yet. The extension gets filtered on startup, so install and reload loops forever.
Workaround: open a normal window using the “Open Editor Window” command in Glass, or start Cursor in classic mode:
cursor --classic
In classic mode, Dev Containers work as usual.
Dev Containers support in Glass is on our radar, but I can’t share an ETA yet. I’m closing this thread as a duplicate so the discussion stays in one place: Dev container remotes don't work with Glass. That thread also has details and updates.