I built a fake news service called Bulldog with four traps baked in, let Claude Code walk into all four, then ran the same prompt again with a fifteen-line CLAUDE.md and it tripped none of them. The video is the whole method. https://www.youtube.com/watch?v=YD4PVx3ygDQ The files are in the Classroom, under Claude Code: the fifteen-line file, the exact three-task prompt, the five-things checklist, the statusline script, and the skill that grades your CLAUDE.md line by line. Start at Tutorials, then The 5 things every CLAUDE.md needs. v1.0 of the CLAUDE.md files, 2026-09-08. And the question from the end of the video: what is one thing you never wrote down but should have for your team? Reply here with some context. That is a line that belongs in your file.