Shopify Deprecates Storefront MCP Cart Tools in Favor of UCP‑Conforming Cart MCP
Migrate get_cart and update_cart to https://{shop-domain}/api/ucp/mcp, include meta ucp-agent.profile and idempotency-key, and send the full line_items array on each update.
Migrate your app to use the new UCP cart MCP tools, update endpoints, include required meta fields, and adjust update_cart payloads to send full line_items array.
Summary
Shopify is deprecating the Storefront MCP cart tools get_cart and update_cart on the https://{shop}.myshopify.com/api/mcp endpoint in favor of UCP‑conforming Cart MCP tools. The new tools are exposed at https://{shop-domain}/api/ucp/mcp and include create_cart, get_cart, update_cart, and cancel_cart. Each request to the new endpoint must carry a meta object with ucp-agent.profile, and cancel_cart requires a meta[\"idempotency-key\"] UUID. The update_cart operation now follows PUT semantics, meaning the entire line_items array must be sent on every update instead of patching individual fields. The deprecated tools will remain functional until August 31 2026, but all documentation will point to the new Cart MCP tools. Migrating now will avoid future breakage when the old endpoints are removed. The change also aligns Shopify’s cart API with the UCP specification version 2026‑04‑08. Developers should review the updated request and response schemas in the Cart MCP documentation.
Key changes
- get_cart and update_cart on https://{shop}.myshopify.com/api/mcp deprecated
- new endpoint https://{shop-domain}/api/ucp/mcp introduced
- new tools: create_cart, get_cart, update_cart, cancel_cart
- update_cart uses PUT semantics, replace full cart state
- each request must include meta ucp-agent.profile
- cancel_cart requires meta[\"idempotency-key\"] UUID
- deprecated tools maintained until Aug 31 2026
- documentation will refer to new Cart MCP tools