Vim as editor for Claws Mail

I got sick of not having Vim as my text editor for emails in Claws Mail but GVim makes my eyes bleed so I wanted proper Vim-in-a-terminal as my editor, which was not particularly straightforward.

The proper incantation was to make a script in my PATH called terminal-vim like this:

#!/bin/bash

mate-terminal --disable-factory -x vim -f "$@"

(gnome-terminal should work similarly if you're in GNOME.)

and to set it as my external editor in Claws Mail by going to Configuration, Preferences, External Programs, and setting Text Editor to terminal-vim '%s'.

Then under Writing in Preferences, I ticked the box "Automatically launch the external editor" and all is well.