I needed to export my macOS Calendar and Reminders for my personal AI assistant. AppleScript fell short, and I couldn't find any existing CLI tool for this. So, using my go-to AI workflow, I had LLMs build a complete Swift tool in about 2 hours. I'm sharing it as a case study on leveraging AI for rapid development in green field projects; the post includes the open-source tool and all the prompts I used.