This is a submission for the Sanity Challenge, Path Two: Vibe-Code Something Strange . What I Built Decision Lab is a small workspace for choices that have no obvious winner. Instead of asking one question and returning a confident answer, it lets people describe the options, name the criteria that matter, assign scores, and then move the importance sliders to see whether their conclusion survives a change in priorities. The demo compares two project ideas: AI Study Planner...