emacs-nox: can't scroll outer claude buffer

[BartMassey]

I'm running emacs-nox on Debian Linux. I can't seem to escape the prompt window in the Claude buffer to scroll up: previous-line works, but the keybindings apparently have me stuck in the prompt window, such that \C-p just scrolls back through the prompt history.

Any suggestions welcome.

[stevemolitor]

Thanks for the report. I can reproduce on macOS with emacs -nw. Graphical emacs is sending wheel-up and wheel-down when I use my trackpad, and apparently that tells Claude Code to scroll up or down in the whole window.

Using emacs -nw, scrolling with the mouse gets translated to keyboard <up> and <down>, which tells Claude to go up or down in the command history, the same as C-p or C-n.

In standalone claude (outside of emacs), the only way I could get it to scroll was using the mouse (or track pad). AFAIK there isn't a keybing to do it.

Here's what did work:

M-x scroll-down and M-x scroll-up did let me scroll up and down the claude window a chunk at a time. You should be able to bind these commands to keys in eat or vterm. Which backend are you using?

Also, claude-code-toggle-read-only-mode (C-c cz) will let you scroll up or down a line at a time using C-p / C-n or the up and down arrows.

[dustinfarris]

I'm not sure if this is the same issue, but I cannot scroll effectively on MacOS (Doom emacs 31) unless I toggle read-only mode via claude-code-toggle-read-only-mode.

erratic.scroll.mov

[dustinfarris]

Also, I don't know if this is the best way to do this, but I've added to my config:

(add-hook 'claude-code-start-hook #'claude-code-read-only-mode)

should this be a custom variable?

[stevemolitor]

I cannot scroll effectively on MacOS (Doom emacs 31) unless I toggle read-only mode via claude-code-toggle-read-only-mode.

To clarify, you can't scroll with the mouse (or trackpad)? I think that's what your video shows. If yes I think that would be a separate issue from this one.

In any case, that's weird. I'm also using MacOS, Emacs 31, but with vanilla Emacs. I do have (setq pixel-scroll-precision-mode t).

Are you using vterm or eat, and does this same thing happen when you run Claude Code inside an eat or vterm session, outside of claude-code.el?

[dustinfarris]

vterm with trackpad.  I’ll check eat and enable pixel precision mode when I get back to my desk

[dustinfarris]

I sat down to reproduce this and it's been a little hit or miss so I'm reluctant to open a new ticket just yet.

Here's my observations so far:

In a *claude buffer using vterm:

Futzing with read-only mode has made this more confusing than repeatable.

For certain though, if read-only mode is enabled, I can scroll just fine as long as the buffer is not busy (e.g. while claude is processing a prompt: animating, generating output, etc).

In a *vterm buffer running claude:

I can scroll just fine if the buffer is not busy.

Enabling pixel-scroll-mode does not appear to have any effect on this behavior.

[stevemolitor]

Here is something I'm experimenting with to avoid the issues running Claude inside eat or vterm: Matisse. It's very bare-bones and alpha at the moment. It's an experiment.

[dustinfarris]

I stumbled upon this: akermu/emacs-libvterm#397 (comment) which is actually working well for me (using vterm for claude-code.el):

(advice-add 'set-window-vscroll :after
  (defun me/vterm-toggle-scroll (&rest _)
    (when (eq major-mode 'vterm-mode)
      (if (> (window-end) (buffer-size))
          (when vterm-copy-mode (vterm-copy-mode-done nil))
        (vterm-copy-mode 1)))))

[stevemolitor]

Oh cool thanks @dustinfarris! I'll test that out a little bit more and maybe add that as an option (default to on?) to claude-code.el.