On Monday, 21 Aug 2017 at 13:21, Jacopo De Simoi wrote:
> tl;dr 
>
> Is there a way to create a token on a subtree header that would count words in 
> the subtree and [optionally] mark a maximum allowed number of words?

I cannot help you directly but what I do is: narrow the region to the
sub-tree while writing and then simply execute M-x count-words RET every
now and again.

There is a wc-mode which displays the number of words/chars in the
modeline but my modeline is already too busy for this...

-- 
: Eric S Fraga via Emacs 26.0.50, Org release_9.0.9-787-g197c58