Feature request: LaTeX math preview in Ghostel buffers

[lemyx]

Use case

I use Ghostel in Emacs to interact with an AI coding assistant. Its responses sometimes contain Markdown-style LaTeX formulas, using $...$ for inline math and $$...$$ for display math.

Ghostel displays the LaTeX source literally. This makes mathematical explanations harder to read, especially formulas with fractions, summations, and square roots.

For example, an explanation of RMSNorm includes:

$$ y_i = \gamma_i \frac{x_i}{\sqrt{\frac{1}{d}\sum_{j=1}^{d}x_j^2+\epsilon}} $$

My current workaround is to save the response to a Markdown file and open it in a math-capable previewer. It works, but interrupts the terminal workflow.

Requested feature

Would it be possible to provide an optional, opt-in way to preview LaTeX formulas from a Ghostel buffer?

Environment

• Ghostel package version: 20260825.1200
• Ghostel commit: d8ee7a9ef523e054d35987349ed14ee1d791aad2
• Emacs version: GNU Emacs 31.1 (development build)
• Emacs revision: a360712c9d27
• Emacs build date: 2026-08-29
• OS: Linux

[dakra]

Hi.
I don't think this is something for Ghostel core, but as a Ghostel buffer is a "normal" (read-only) buffer I thought
that shouldn't be hard to implement.
I googled and found a GNU ELPA package mathjax and that worked out of the box without changing something. I.e. (mathjax-typeset-region (point-min) (point-max)))))) worked on your example.

I asked my clanker to write a short minor-mode that hooks on either command-finish or the new osc7501 finished function
so this is run every time you're either in a new shell prompt or your AI finished a task.

Obviously very minimal and could be improved I guess, but it just shows how easy it is to extend Ghostel :)

(require 'mathjax)

(defun ghostel-mathjax-typeset (&optional buffer)
  "Render the formulas in BUFFER (default: current buffer) as images."
  (interactive)
  (let ((buffer (or buffer (current-buffer))))
    (when (buffer-live-p buffer)
      (with-current-buffer buffer
        (mathjax-typeset-region (point-min) (point-max))))))

(defun ghostel-mathjax--typeset-soon (&rest _)
  "Typeset the current buffer once the pending output is drawn."
  (run-at-time 0.2 nil #'ghostel-mathjax-typeset (current-buffer)))

(defun ghostel-mathjax--on-status (_id old new)
  "Typeset when a program (e.g. Claude Code) stops working."
  (when (and (eq (plist-get old :state) 'working)
             (not (eq (plist-get new :state) 'working)))
    (ghostel-mathjax--typeset-soon)))

(define-minor-mode ghostel-mathjax-mode
  "Render LaTeX formulas in this ghostel buffer as images."
  :lighter " TeX"
  (if ghostel-mathjax-mode
      (progn
        (add-hook 'ghostel-command-finish-functions #'ghostel-mathjax--typeset-soon nil t)
        (add-hook 'ghostel-program-status-functions #'ghostel-mathjax--on-status nil t)
        (ghostel-mathjax-typeset))
    (remove-hook 'ghostel-command-finish-functions #'ghostel-mathjax--typeset-soon t)
    (remove-hook 'ghostel-program-status-functions #'ghostel-mathjax--on-status t)
    (remove-overlays nil nil 'category 'mathjax)))

(add-hook 'ghostel-mode-hook #'ghostel-mathjax-mode)

Let me know what you think.