IdeaGauntlet is an open-source CLI + MCP server that stress-tests a product idea with adversarial AI agents — a multi-role "court" debate, synthetic user objections, and grounded scoring. It won't cheerlead: it looks for the fastest way your idea dies while it's still cheap to kill. Run it in your terminal (bring your own model) or key-free inside Claude Code / Cursor. MIT-licensed.