`/add-dir` works with `~` but not `$HOME` for home directories

[mxie]

Describe the bug

$HOME is a commonly used to refer to the home directory, and I referred to it when trying to add a directory to the allow list. However, Copilot CLI doesn't seem to know how to expand it the same way it does for ~. As a result, the directory was not successfully added to the allow list despite /add-dir saying it was "added" which was misleading.

CleanShot.2025-09-30.at.12.58.mp4

Affected version

0.0.330; Commit: a8bfefe

Steps to reproduce the behavior

1. Run /add-dir with a path that refers to $HOME (or maybe any variable)
   • You should see: Added directory to allowed list: <path with variable in raw form>
2. Run /list-dirs
   • You should see: new path not listed

Expected behavior

A few possibilities here, but the gist is that I would've expected any behavior that was clear about what worked / what didn't. For example:

1. The new path to be added (in raw or expanded form)
2. A successful message was not shown when the path wasn't actually added
3. Support for tab-completion so that the path can be auto-expanded, increasingly the likelihood of it being added successfully

Additional context

• macOS on ARM
• iTerm2
• zsh