Direct answer
Shopify Agentic Storefronts is the Shopify feature that makes a store's products discoverable and purchasable in AI channels such as ChatGPT, Microsoft Copilot, Google AI Mode, and Gemini. It is active by default for eligible stores, managed under Sales channels > Agentic, and it reports AI-channel performance in the admin. It handles distribution; it does not make agents prefer your products.