How I built a fully automated, rule-based Japanese stock research pipeline with Claude Code, J-Quants, and a macOS cron job — and why "the AI is not allowed to predict anything" turned out to be the most useful constraint in the whole project. Everyone's first idea for "AI + stocks" is the same: ask the model whether a stock will go up. That idea has been tested, and it fails — LLMs guessing post-event price direction land around coin-flip accuracy. I'm a freelance web developer in Japan,...