Snipped for org-mode agenda to show presence of notes

init.el

(with-eval-after-load 'org-agenda
  (defun my/org-has-children ()
    (if (save-excursion (org-goto-first-child)) "▶" " ")
  )
  (add-to-list 'org-agenda-prefix-format '(
     agenda  . "%i%-3:(my/org-has-children) %-12:c%?-12t% s "
  ))
)

; Result:
;  ▶ apt:        D         TODO   [#A] pay council tax                                                 :bills:
;  ▶ backup:     D         TODO   [#C] Bookmark Archiver https://pirate.github.io/bookmark-archiver    :backup:
;    social:     D         TODO   [#B] check meetups                                                   :social::