Tag org-pomodoro entries

foo.el

(defvar my/org-pomodoro-analyzer-tag "POMODORO"
  "Tag to add to an org entry when org-pomodoro clocks in.")

(defun my/org-pomodoro-analyzer-advice (_)
  "If a pomodoro is running we ensure that it has a tag
`my/org-pomodoro-analyzer-tag'."
  (when (org-clock-is-active)
    (save-window-excursion
      (with-current-buffer (org-clock-is-active)
        (org-clock-goto)
        (org-toggle-tag my/org-pomodoro-analyzer-tag 'on)))))

(defun my/org-pomodoro-analyzer-enable ()
  "Enable tagging org-pomodoro entries."
  (interactive)
  (message "org-pomodoro-analyzer tagging enabled")
  (advice-add 'org-pomodoro :after 'my/org-pomodoro-analyzer-advice))

(defun my/org-pomodoro-analyzer-disable ()
  "Disable tagging org-pomodoro entries."
  (interactive)
  (message "org-pomodoro-analyzer tagging disabled")
  (advice-remove 'org-pomodoro 'my/org-pomodoro-analyzer-advice))

(use-package org-pomodoro
  :ensure
  :config
  (my/org-pomodoro-analyzer-enable))