To enable formatting in Emacs, add the following to your .init.el:

;; if using SLIME
(setq lisp-indent-function 'common-lisp-indent-function)

;; if using Sly
(setq lisp-indent-function 'sly-common-lisp-indent-function)

(modify-syntax-entry ?\[ "(]" lisp-mode-syntax-table)
(modify-syntax-entry ?\] ")[" lisp-mode-syntax-table)

Now everything will be indented nicely[^1] and is read as s-expressions the same as any other lisp code, which allows for Scrawl to be seamlessly integrated into a structural editing workflow.

Scrawl will be considered in a 1.0 release state when it is possible to write something like [# section \n\n etc] and have it be formatted in Emacs the following way:

[# section title

 text with [* bold text]

 [# subsection

  more text]

 more text in higher level]

Every line should be indented to the start of the s-exp, but because of how lisp formatters work in Emacs and because of my limited knowledge of Emacs Lisp, there is no clear way that I am aware of as of now for how to read the brackets as s-exps but also have them formatted as plain data lists. I am not going to write an entire mode for something that is supposed to be able to be embedded within Common Lisp, so for the time being am recommending to add a dispatch character #[# section ...] to trick the formatter into indenting Scrawl nicely.