WebToffee Universal Commerce Protocol Enabler for Woocommerce
WebToffee Universal Commerce Protocol Enabler for Woocommerce integrates your store with the Universal Commerce Protocol — the open standard that lets AI assistants (Google AI Mode, Gemini, ChatGPT, and others) discover, browse, and purchase from your store without custom builds for each platform.
Once activated, two things happen automatically:
- A discovery profile is published at
/.well-known/ucp— the standard entry point that AI platforms fetch to learn what your store supports. - REST endpoints go live at
/wp-json/wt-ucp/v1/— implementing the five standard UCP capabilities.
Capabilities
Checkout (dev.ucp.shopping.checkout)
Create, update, and complete checkout sessions. An AI agent calls POST /checkout-sessions with a list of items and buyer details, updates it with shipping info via PUT, then finalises payment via POST .../complete. Sessions map directly to WooCommerce pending orders.
Cart (dev.ucp.shopping.cart)
Session-based basket building before a purchase is ready to commit. The agent creates a cart with POST /carts, then optionally hands it off to the human buyer via a continue_url that loads items into the WooCommerce frontend cart and redirects to the cart page.
Order (dev.ucp.shopping.order)
Lets agents check the status of any order using GET /orders/{id}, covering the full WooCommerce order lifecycle from pending to fulfilled.
Catalog (dev.ucp.shopping.catalog)
Product search via GET /catalog/search and individual item lookup via GET /catalog/items/{id}. Returns prices in minor currency units as required by the spec.
Discount (dev.ucp.shopping.discount)
Extends the Cart and/or Checkout capabilities with coupon code support. An agent submits discounts.codes inside any Cart or Checkout create/update request. The plugin validates each code against WooCommerce coupons, applies the discount, and returns the structured discounts.applied array alongside updated line-item and order-level totals. Coupons applied automatically by WooCommerce hooks are surfaced as automatic: true entries. Supports percent, fixed_cart, and fixed_product WooCommerce coupon types. Rejected codes are returned as typed messages entries (e.g. discount_code_expired, discount_code_combination_disallowed).
Discount Behaviour
- Replacement semantics — each Cart or Checkout PUT replaces the full set of applied codes. Send an empty
discounts.codesarray to clear all discounts. - Cart sessions — discounts are computed entirely in PHP against
WC_Couponwithout requiring a live WooCommerce cart session. Per-lineitems_discounttotals are injected intoline_items[].totalsand the cart-leveltotalsarray. - Checkout sessions — discounts are applied directly to the WooCommerce order via
$order->apply_coupon().$order->calculate_totals()is called automatically; the response reflects WooCommerce’s authoritative totals. - Total types — line-item-level discounts appear as
items_discountentries; order-level discounts appear asdiscountentries, matching the UCP spec distinction. - Automatic coupons — coupons applied by a WooCommerce hook (not in the submitted codes) are returned in
discounts.appliedwith"automatic": trueand nocodefield.
REST Endpoints
Method Path Capability
GET
/wp-json/wt-ucp/v1/catalog/search
Catalog
GET
/wp-json/wt-ucp/v1/catalog/items/{id}
Catalog
POST
/wp-json/wt-ucp/v1/carts
Cart
GET
/wp-json/wt-ucp/v1/carts/{id}
Cart
PUT
/wp-json/wt-ucp/v1/carts/{id}
Cart
POST
/wp-json/wt-ucp/v1/checkout-sessions
Checkout
GET
/wp-json/wt-ucp/v1/checkout-sessions/{id}
Checkout
PUT
/wp-json/wt-ucp/v1/checkout-sessions/{id}
Checkout
POST
/wp-json/wt-ucp/v1/checkout-sessions/{id}/complete
Checkout
POST
/wp-json/wt-ucp/v1/checkout-sessions/{id}/cancel
Checkout
GET
/wp-json/wt-ucp/v1/orders/{id}
Order
Discount codes are submitted as discounts.codes inside the Cart and Checkout create/update request bodies — no separate endpoint is needed.
Settings
Go to WooCommerce → UCP Enabler to configure:
- General — UCP protocol version, API base endpoint (for proxied setups), profile cache TTL.
- Capabilities — Toggle individual capabilities on or off using the switch controls. The Discount toggle is only effective when Cart or Checkout (or both) are also enabled.
- Payment Handler — Configure a PSP tokenizer: token retrieval URL, public key, and accepted card brands.
Payment Processing
The plugin handles the UCP protocol layer and stores the payment token in WooCommerce order meta (_ucp_payment_token). The actual charge against your PSP is delegated via a WordPress filter, giving you full control:
php
add_filter( 'wbte_ucp_enabler_process_payment', function( $result, $order, $instrument, $credential ) {
// $credential['token'] is the PSP token sent by the agent.
// Call your payment gateway SDK here.
// On success: return null (or call $order->payment_complete($tx_id) first).
// On failure: return a WP_Error.
return null;
}, 10, 4 );
Cart Handoff
When an agent builds a cart for a human buyer to finish, the continue_url in the cart response is a one-time link that loads all items into the WooCommerce session and redirects to the WooCommerce cart page. The token is consumed on first use. Any discounts applied to the cart are preserved in the transient and will be visible in the response on subsequent GETs.
Item ID Convention
UCP uses a single string item.id to identify products. The plugin maps:
* "123" → WooCommerce product ID 123
* "123-456" → WooCommerce product 123, variation 456
The catalog endpoint returns variation IDs in "{product_id}-{variation_id}" format so agents can reference them directly. Override with the wbte_ucp_enabler_resolve_item_id filter for custom slug-based IDs.
Extend the Profile
php
add_filter( 'wbte_ucp_enabler_profile', function( $profile, $settings ) {
// Add signing_keys, custom extensions, etc.
return $profile;
}, 10, 2 );
External services
This plugin does not send any data to WebToffee or to any third party by itself. However, its entire purpose is to let external AI shopping agents (Google AI Mode, Gemini, ChatGPT, and others that implement the Universal Commerce Protocol) call your own store’s REST API to browse your catalog and place orders — this section documents that data flow.
Universal Commerce Protocol (ucp.dev) schema references. The /.well-known/ucp profile and the plugin’s REST responses embed several fixed URLs like https://ucp.dev/{version}/schemas/shopping/checkout.json and https://ucp.dev/{version}/specification/overview. These are static links to the public UCP specification/schema documentation, included so that any AI agent reading your profile knows which version of the protocol and JSON schema your store implements. Your server does not call these URLs at runtime and no store or customer data is ever sent to ucp.dev; the links are descriptive metadata only, and only the requesting agent (not this plugin) may choose to resolve them. ucp.dev is an open specification site (not a paid service) published under the Apache License 2.0.
Service: Universal Commerce Protocol specification (ucp.dev), an open standard maintained by the UCP Authors (Google, Shopify, and other industry partners) on GitHub.
Specification & source: https://github.com/Universal-Commerce-Protocol/ucp
License: https://github.com/Universal-Commerce-Protocol/ucp/blob/main/LICENSE
Inbound requests from AI shopping agents. Once activated, this plugin exposes REST endpoints (catalog, cart, checkout, order) under /wp-json/wt-ucp/v1/. Any AI platform or agent that supports UCP can call these endpoints directly to search your catalog, build a cart, and complete checkout — this is the plugin’s core function, not an optional integration. Catalog search/lookup is open to any caller. Checkout-session and order operations beyond creation require the caller to present the session token issued at checkout creation (delivered via an X-UCP-Session-Token response header, and presented back as a standard Authorization: Bearer <token> header, per the UCP REST binding’s own guidance on authenticating individual operations) — so an agent can only read or modify a session it created itself. No background or scheduled data transmission occurs; every exchange is a direct response to a request initiated by the agent. Which AI platforms can reach your store depends entirely on which agents or vendors you choose to make your /.well-known/ucp profile known to; this plugin does not register your store with, or transmit data to, any specific AI vendor on its own.
Optional payment handler / tokenizer. If you configure a Payment Handler under Settings, card/payment data is tokenized by the handler you choose to configure. Consult that provider’s own terms of service and privacy policy, as it is not bundled with or endorsed by this plugin.