Here is a short description of how to use Kate's GPTer:

Command	Description
.chat	Generate the next line using the channel's chat history as a prompt.
.chat blah	when you do .chat blah, it adds to that prompt a last line containing "blah" but "blah" isn't added to the per-chat history buffer. so it's like a temporary thing.
.chatas kate	when you do .chatas kate, it generates the next line but starting with "<kate>" so it simulates what kate would say next
.chatas kate blah	when you do .chatas kate blah, it does the same thing as .chat blah but also adds "<kate>" for the next line, so it's like what kate would say in response to blah
.complete kate blah	when you do .complete kate blah, it takes <kate> blah ... and fills in the "..." part and prints it out

Additionally, you can prepend any above command with a "clean", like ".cleanchatas", to ignore the channel's chat history and perform any completions from a blank slate.

!! TEXT	Escapes TEXT. GPTer will ignore anything written on this line entirely.
.nick NAME	Set GPTer's nickname. GPTer will talk as this person. Like .chatas but permanant. Default is gpter.
.history TRIM_START TRIM_TARGET	Set the maximum history length to TRIM_START and trim it down to TRIM_TARGET each time it reaches it. Default is 800 200.
.spoof NICK TEXT	Make GPTer think that the TEXT you typed was typed by NICK (can be supplied as gpter).
.wipe	Clear GPTer's history.
.temp TEMPERATURE [REPETITION_PENALTY]

.fill based | gender | letterman | opposite | poem | rate_abuse | translate text="TEXT"

Cool stuff.