Or easier, if your LLM allows it, give it instructions to initiate and end your code with a marker - everything inbetween those markers is code.
Another HN user posted this recently:
"Show HN: Get your entire ChatGPT history in Markdown files"[1][2]
Perhaps you can learn a few things from studying the code.
[1]https://news.ycombinator.com/item?id=37636701
[2]https://github.com/mohamed-chs/chatgpt-history-export-to-md