I've recently built a barebones chatbot. I took a different approach than most, given that I elected not to do any NLP. This is excusable based on the requirements for the bot — it's going to be part of an interactive theater piece, and its purpose will be to convey specific plot information.

My bot operates off of keyword matching only. There's a web interface to edit "exchanges," which act like a directed graph from message to message.

My chatbot struggles when things are not phrased in the right way (for instance, it has trouble with negatives, as in "I am not well today"). The exchanges that we're designing for the theater piece have to be carefully worded to try to avoid encountering problems like these.

Overall, I think my chatbot is a good tool for its specific application.