You are drafting in a browser text field and want to tighten or grow the text without copy-pasting into another tab.
Text actions work on any selection on any page. In editable fields the result can be inserted straight back into the field; on ordinary selections it opens in the panel to copy. The model used for text actions is configurable, so you can point drafts at a stronger model and quick fixes at a fast, cheap one.
Select the passage, run rewrite, shorten, or expand, and insert or copy the result. One caveat: on some sites that aggressively block extensions, in-page text actions may not appear; see the article on site blocking in the Troubleshooting category.