On September 2, Anthropic open-sourced Claude Commerce Agents — an Apache 2.0 blueprint with a storefront shopping agent that searches, compares, builds carts, and hands off to the merchant's own checkout, plus a merchant-side agent for listings, pricing, and campaigns. Shopify shipped a working implementation the same day. The contrast with OpenAI's retired in-chat checkout (killed in March after conversions sank) shows the strategic fork: gateway vs merchant control. Whoever owns the agent-friendly interface to a store owns the next retail distribution.