In the GitHub Wiki I added a new page on Practical STM8S eForth Programming.

All you need is your favorite serial terminal program, and a text editor on your host (I now use picocom and ascii-xfr allong with gVim).

FILE
( lines 
  with code and instructions
  here )
HAND

Edit: there is a new word RESET for resetting the NVM contents to default (startup, dictionary etc). I also reduced the memory footprint of CORE to 4620 bytes. A full featured MINDEV binary uses 5360 bytes (incl. background task and compile to Flash), and a W1209 binary requires 5699 bytes incl. 7S-LED, keys, and half-duplex serial interface.