@@ -368,6 +368,7 @@ const card = await kernel.vaults.items.upsert("notebook-order", {
     merchant: "example shop",
     amount: 2306,
     currency: "usd",
+    checkout_origin: "https://shop.example.com",
   },
 });
 
@@ -392,6 +393,7 @@ card = kernel.vaults.items.upsert(
         "merchant": "example shop",
         "amount": 2306,
         "currency": "usd",
+        "checkout_origin": "https://shop.example.com",
     },
 )
 
@@ -411,7 +413,8 @@ kernel vaults cards create user-12345 notebook-order \
     "wallet": "agentcard-wallet",
     "merchant": "example shop",
     "amount": 2306,
-    "currency": "usd"
+    "currency": "usd",
+    "checkout_origin": "https://shop.example.com"
   }'
 kernel vaults items get user-12345 notebook-order -o json
 ```
@@ -420,6 +423,25 @@ kernel vaults items get user-12345 notebook-order -o json
 
 `amount` uses minor currency units, so `2306` means 23.06 usd. omitting `card_id` lets the cardholder select an enrolled card on the approval screen. to pin a card, request the wallet's advertised `payment_methods` expansion and set a returned id as `spec.card_id`.
 
+`checkout_origin` is optional. set it to the checkout's canonical origin: an
+HTTPS origin with a lowercase host, no default port, and no path (for example,
+`https://shop.example.com`), or an HTTP `localhost` origin for local test
+pages (for example, `http://localhost:3000`). For non-prepared checkout
+authorizations, Kernel sends this caller-supplied origin to AgentCard for
+cardholder autopilot rule matching. This origin match isn't payment approval
+itself: an eligible autopilot rule can authorize the request, while an
+ineligible rule can still fall back to user approval. If you omit the field,
+the existing approval behavior remains. Prepared checkout uses the
+`merchant_origin` from its preparation instead of this field. Card updates
+replace the full `spec`, so include `checkout_origin` again when you want to
+keep using it. An autopilot match doesn't guarantee processor acceptance or
+payment success.
+
+Kernel doesn't compare `checkout_origin` with the browser's current page. Your
+application must derive or validate the origin from a trusted checkout context
+and must not treat it as proof of the page's identity. Continue to verify the
+merchant and purchase independently before checkout submission.
+
 ### Reuse a card item for a new purchase
 
 `upsert` can retrieve an identical item, but it cannot replace the purchase
@@ -451,6 +473,7 @@ reusableCard = await kernel.vaults.items.update("notebook-order", {
     merchant: "example books",
     amount: 4199,
     currency: "usd",
+    checkout_origin: "https://books.example.com",
   },
 });
 ```
@@ -480,6 +503,7 @@ reusable_card = kernel.vaults.items.update(
         "merchant": "example books",
         "amount": 4199,
         "currency": "usd",
+        "checkout_origin": "https://books.example.com",
     },
 )
 ```
@@ -492,7 +516,8 @@ kernel vaults cards update user-12345 notebook-order \
     "wallet": "agentcard-wallet",
     "merchant": "example books",
     "amount": 4199,
-    "currency": "usd"
+    "currency": "usd",
+    "checkout_origin": "https://books.example.com"
   }'
 ```
 
@@ -721,7 +746,7 @@ wallet and card items accept these `spec` fields. fields not listed here are rej
 | item | required fields | optional fields |
 | --- | --- | --- |
 | wallet | `provider: 'agentcard'` | `provider_config`; `user_id` for a user already enrolled in the organization under the same configuration |
-| card | `provider`, `wallet`, `merchant`, `amount`, `currency`                                                      | `card_id`                                        |
+| card | `provider`, `wallet`, `merchant`, `amount`, `currency`                                                      | `card_id`, `checkout_origin`                    |
 
 agentcard accepts amounts from 1–9007199254740991 and a three-letter `currency`. `merchant` accepts 1–120 printable characters without control characters. `card_id` uses the provider's `vc_` identifier, and wallet `user_id` uses its `usr_` identifier.