Condy Chen <condy0919@gmail.com> writes:

> By defining `foo' with
>
> (defun foo (arg)
>   (interactive "p" org-mode)
>   (message "foo"))
>
> M-x foo is still available in elisp-mode.

Try

(setq read-extended-command-predicate 'command-completion-default-include-p)


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