Validate Agent

This validation agent checks your technical plan against current best practices before you start building. It extracts every tech choice from your plan, queries a RAG system to see if similar approaches worked or failed in the past, then hits the web to verify libraries and patterns are still recommended in 2024-2025. You get back a handoff that flags anything deprecated, risky, or outdated with specific alternatives. The nice bit is it distinguishes between "this will break" and "this is fine but there's something newer," so you're not blocked on minor stuff. Runs on Haiku to keep costs down since it's basically doing research and summarization, not complex reasoning.