📝 Open-weight models take 56% of token volume, Astra doubles Fable 5.1 spend AI Gateway Production Index — September 2026 Every month, AI Gateway routes tens of trillions of tokens between production applications and AI labs. That traffic gives us a view of what AI usage actually looks like in today's enterprise, and we publish it here monthly. See the Production Index reports from June, July, and August. September 2026 summary The September index reports on AI Gateway data collected through…