diff --git a/docs/playground.md b/docs/playground.md
index 983a6ff2..8042006c 100644
--- a/docs/playground.md
+++ b/docs/playground.md
@@ -961,7 +961,7 @@ class UcpApp {
   }
 
   prepareUpdatePayload(checkoutResponse) {
-    const patch = { id: checkoutResponse.id };
+    const patch = { id: checkoutResponse.id }; // deprecated: id is redundant with URL path
     const errors = checkoutResponse.messages || [];
 
     if (errors.some(e => e.path === "$.buyer.email")) {
diff --git a/docs/specification/checkout-rest.md b/docs/specification/checkout-rest.md
index 8b2e2035..df42a62a 100644
--- a/docs/specification/checkout-rest.md
+++ b/docs/specification/checkout-rest.md
@@ -182,7 +182,7 @@ so clients must include all previously set fields they wish to retain.
     Content-Type: application/json
 
     {
-      "id": "chk_123456789",
+      "id": "chk_123456789", // deprecated: id is redundant with URL path
       "buyer": {
         "email": "jane@example.com",
         "first_name": "Jane",
@@ -310,7 +310,7 @@ type & addresses.
     Content-Type: application/json
 
     {
-      "id": "chk_123456789",
+      "id": "chk_123456789", // deprecated: id is redundant with URL path
       "buyer": {
         "email": "jane@example.com",
         "first_name": "Jane",
@@ -512,7 +512,7 @@ Follow-up calls after initial `fulfillment` data to update selection.
     Content-Type: application/json
 
     {
-      "id": "chk_123456789",
+      "id": "chk_123456789", // deprecated: id is redundant with URL path
       "buyer": {
         "email": "jane@example.com",
         "first_name": "Jane",
diff --git a/source/schemas/shopping/checkout.json b/source/schemas/shopping/checkout.json
index 9e23b778..5e458333 100644
--- a/source/schemas/shopping/checkout.json
+++ b/source/schemas/shopping/checkout.json
@@ -25,7 +25,7 @@
       "description": "Unique identifier of the checkout session.",
       "ucp_request": {
         "create": "omit",
-        "update": "required",
+        "update": {"from": "required", "to": "omit", "description": "The id field from the transport request is expected to be used."},
         "complete": "omit"
       }
     },