This feels like a very @SwiftOnSecurity story but I’m going to tell it.
Chat bots (not just LLM driven) are surprisingly old. In the mid 90s, a mark up language for string-driven bots called AIML was released. A small community of early hackers and devs got really into it. I was part as a teen.
To use AIML, you had to know a lot about computers. You had to really understand how it worked to build your own chat bot. It could learn over time by building a database of string based responses. You could hard code responses to full and partial strings like words and phrases. It was hard work.