Most AI demos look impressive when 5 people are using them. Things get very different when hundreds of people are simultaneously asking your system to: maintain long-running conversational memory coordinate shared game state across multiple players handle real-time Discord interactions retrieve contextual campaign knowledge stream AI responses quickly enough to feel conversational and do all of it without your API bill exploding Over the last year, I built Scrollbook, an AI-powered tabletop RPG platform designed to act as a persistent AI Game Master inside Discord. At its peak, Scrollbook organically grew to 867 Discord servers and more than 1,000 active users. I built the entire system solo. And eventually, I had to shut it down. Not because the product failed. Because the infrastructure and model costs became unsustainable for me to continue operating alone. That experience completely changed how I think about AI systems engineering. The hardest part was never prompting Claude.…