AI SaaS validation is what separates a real business from a zombie company — an app with glowing reviews that's bleeding to death financially. This episode is the complete pre-build playbook for 2026: Steve Blank's customer development manifesto applied to vibe coding, how to mine Reddit for high-intensity pain using the frequency vs intensity matrix, and how the Idea Sieve agent (730-line system prompt, two-model routing at 12–15 cents per run) automates brutal idea destruction before you write a line of code. Plus the fake door test with real benchmarks (cold traffic: 0.44%–0.65% CTR, warm community traffic: 15%–25% opt-in rate), the Astra AI margin trap case study (170K users, $125K–$250K/month in OpenAI bills, 39–69% gross margin before salaries), how Lovable hit $200M ARR in 12 months with a credit-based model that scales with compute cost,  ...