Described in the September 2026 paper Design Docs Are All You Need (arXiv 2609.05364) by DeepMind, MIT, Stanford, and Google-affiliated authors, SMART keeps almost no hand-authored implementation on main. Humans edit ~50 design docs (~9k lines of prose) with worked examples; an orchestrator walks a doc DAG and coding sub-agents regenerate the library (reported ~1.5–3 hours and ~$100 per full rebuild). A recursive Op IR with SymPy cost expressions supports fast analytical and slow modulo-scheduling roll-ups; regenerated models matched hand-audited DeepSeek-V3 TPU serving references to round-off.