[ci] preview release (preview)

.changeset/pre.json

@@ -2,12 +2,13 @@
   "mode": "pre",
   "tag": "preview",
   "changesets": [
-    "accept-variant-id",
-    "bright-agents-proxy",
-    "calm-carts-refresh",
-    "clean-cursors-paginate",
-    "fair-prices-render",
-    "fec-produce-well-known",
-    "quick-plums-develop"
+    "account-script",
+    "cart-metafields-skill",
+    "mock-shop-store-catalog",
+    "product-line-attributes",
+    "quiet-cart-aborts",
+    "skills-check-command",
+    "skills-sync-command",
+    "ucp-mcp-proxy"
   ]
 }

packages/hydrogen/CHANGELOG.md

@@ -1,5 +1,23 @@
 # @shopify/hydrogen
 
+## 2026.10.0-preview.3
+
+### Minor Changes
+
+- 8827904: Add an `account` option to `getShopifyScriptTags()` and the React/Vue `ShopifyScripts` components. When enabled, Hydrogen loads the Shopify customer account web component (`https://cdn.shopify.com/storefront/web-components/account.js`) with the same nonce and `crossorigin` handling as the other Shopify runtime scripts. Render `<shopify-account>` where you want the account UI to appear. The script URL is also exported as `SHOPIFY_ACCOUNT_SCRIPT`.
+- 96f9d2d: Add `register("attributeValue", { key, value })` to `ProductFormRegister` for attaching line-item attributes (engraving text, gift messages, custom options) through the form-based add-to-cart path. Both client-side (`getAddPayload`) and server-side (`parseAddIntent`) now extract `attributes.*` entries from FormData. Exports two new types: `ProductAttributeValueProps` and `ProductAttributeDefaultValueProps`.
+- d92f398: Add `hydrogen skills check`, which exits non-zero when the project's synced skills do not match the installed `@shopify/hydrogen`, or were never synced. It prints the summary `skills sync` would act on and writes nothing. The default `--mode=error` gates CI; `--mode=warn` prints the same message and exits zero for dev scripts.
+- 05e43e6: Add `hydrogen skills sync` to keep packaged agent skills aligned with the installed `@shopify/hydrogen` version. Skills are always written to both `.claude/skills` and `.agents/skills`, covering Claude Code, Codex, Cursor, and OpenCode without configuration. Each copied `SKILL.md` records the package version and a content hash under frontmatter `metadata`. Rerunning the command after an upgrade overwrites unmodified skills, adds new ones, removes skills the package no longer ships, and leaves locally modified skills alone unless `--force` is passed. If you edited a skill the package no longer ships, you are asked before it is removed; without a terminal (for example in CI) it is kept and a warning is printed. `hydrogen setup` runs the same sync after installing the package and accepts the same `--force`, so rerunning it over previously synced skills now updates them instead of failing. Preview templates ship their skills with the same metadata, so `skills sync` works on deployed templates too.
+
+  Projects that ran `hydrogen setup` before this version have skills without the metadata block. Run `npx @shopify/hydrogen skills sync --force` once to adopt them; later syncs then manage them normally. Skills from those earlier copies whose names are no longer shipped are not recognised and should be deleted by hand.
+- 54a1e7e: Proxy caller-authenticated UCP MCP requests from `/api/ucp/mcp` to the configured Shopify store.
+
+### Patch Changes
+
+- d8f8476: Add the `hydrogen-cart-metafields` skill: a behavioral guide for reading and writing cart metafields (custom cart data such as delivery instructions) through a custom `CartFragment`, an app-owned mutation route, and `useCartActions().refresh()`.
+- a6e3a71: Cart permalinks now hand off to the mock.shop demo store for every mock.shop host, not only `mock.shop` itself, so a storefront built against a per-store host such as `pets.mock.shop` behaves the same in mock mode. The `hydrogen-storefront-client` and `hydrogen-setup` skills now explain that mock.shop is a catalog of stores and how to pick one from https://mock.shop/llms.txt.
+- c35ee9d: Prevent superseded cart mutations from producing unhandled `AbortError` console errors.
+
 ## 2026.10.0-preview.2
 
 ### Minor Changes

packages/hydrogen/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@shopify/hydrogen",
-  "version": "2026.10.0-preview.2",
+  "version": "2026.10.0-preview.3",
   "description": "Framework-agnostic Shopify storefront SDK and agent skills.",
   "license": "MIT",
   "author": "Shopify",