kitty

kitty is not the default, to use it you will have to add this line to your .vimrc:

let g:slime_target = "kitty"

When you invoke vim-slime for the first time, you will be prompted for more configuration.

kitty target window

This is the id of the kitty window that you wish to target. See e.g. the
value of $KITTY_WINDOW_ID in the target window.

kitty listen on

Specifies where kitty should listen to control messages, by default the
value of $KITTY_LISTEN_ON in the target window.

To work properly, kitty must also be started with the following options:

kitty -o allow_remote_control=yes --listen-on unix:/tmp/mykitty

See more here. This can also be added to your kitty.conf file as:

allow_remote_control yes
listen_on unix:/tmp/mykitty

SSH

For slime use over ssh, you can also forward the remote control.

Note the additional security concerns, however: this should only be done on trusted remote hosts.

bracketed-paste

Some REPLs can interfere with your text pasting. The bracketed-paste mode exists to allow raw pasting.

kitty supports bracketed-paste, use:

let g:slime_bracketed_paste = 1
" or
let b:slime_bracketed_paste = 1

(It is disabled by default because it can create issues with ipython; see #265).