@MattPaulsonSD You can do it, but it's still rudimentary.

You can create a Custom GPT on @OpenAI, and upload everything you've written in a single text file.

https://help.openai.com/en/articles/8554397-creating-a-gpt

However, it's still prone to hallucinations:
https://ruk.ca/content/creating-custom-gpt-learn-about-my-blog-and-about-myself