diff --git a/docs/specification/shopping/extensions/discount.md b/docs/specification/shopping/extensions/discount.md
index 4b538d503..34f628ea5 100644
--- a/docs/specification/shopping/extensions/discount.md
+++ b/docs/specification/shopping/extensions/discount.md
@@ -18,25 +18,25 @@
 
 ## Overview
 
-Discount extension allows businesses to indicate that they support discount
-codes on cart and checkout sessions, and specifies how the discount codes are
-to be shared between the platform and the business.
+The Discount extension allows Businesses to surface discoverable promotions on
+product details and to support discount codes on Cart and Checkout sessions.
 
 **Key features:**
 
 - Submit one or more discount codes
+- Discover public promotion previews before Cart creation
 - Receive applied discounts with human-readable titles and amounts
 - Rejected codes communicated via `messages[]` with detailed error codes
 - Automatic discounts surfaced alongside code-based discounts
 
 **Dependencies:**
 
-- Cart Capability or Checkout Capability
+- Catalog Lookup, Cart, or Checkout Capability
 
 ## Discovery
 
 Businesses advertise discount support in their profile. The capability can
-extend cart, checkout, or both:
+extend Catalog Lookup, Cart, Checkout, or any combination of them:
 
 <!-- ucp:example schema=profile def=business_schema extract=$.ucp.capabilities target=$.ucp.capabilities -->
 ```json
@@ -47,7 +47,11 @@ extend cart, checkout, or both:
       "dev.ucp.shopping.discount": [
         {
           "version": "{{ ucp_version }}",
-          "extends": ["dev.ucp.shopping.cart", "dev.ucp.shopping.checkout"],
+          "extends": [
+            "dev.ucp.shopping.catalog.lookup",
+            "dev.ucp.shopping.cart",
+            "dev.ucp.shopping.checkout"
+          ],
           "spec": "https://ucp.dev/{{ ucp_version }}/specification/shopping/extensions/discount",
           "schema": "https://ucp.dev/{{ ucp_version }}/schemas/shopping/discount.json"
         }
@@ -57,19 +61,29 @@ extend cart, checkout, or both:
 }
 ```
 
-Businesses MAY advertise discount support for cart only, checkout only, or
-both. Platforms SHOULD check which resources are extended before submitting
-discount codes.
+Businesses MAY advertise discount support for any subset of these capabilities.
+Platforms SHOULD check which resources are extended before presenting promotion
+previews or submitting discount codes.
 
 ## Schema
 
-When this capability is active, cart and/or checkout are extended with a
-`discounts` object.
+When this capability is active, the negotiated Catalog Lookup, Cart, and/or
+Checkout operations are extended with a `discounts` object. Catalog adds the
+object only to `get_product` responses; Cart and Checkout also accept discount
+codes in requests.
 
 ### Discounts Object
 
 {{ extension_schema_fields('discount.json#/$defs/discounts_object', 'shopping/extensions/discount') }}
 
+### Catalog Discounts Object
+
+{{ extension_schema_fields('discount.json#/$defs/catalog_discounts_object', 'shopping/extensions/discount') }}
+
+### Available Discount
+
+{{ extension_schema_fields('discount.json#/$defs/available_discount', 'shopping/extensions/discount') }}
+
 ### Applied Discount
 
 {{ extension_schema_fields('discount.json#/$defs/applied_discount', 'shopping/extensions/discount') }}
@@ -78,6 +92,75 @@ When this capability is active, cart and/or checkout are extended with a
 
 {{ extension_schema_fields('discount.json#/$defs/allocation', 'shopping/extensions/discount') }}
 
+## Catalog Promotion Previews
+
+When the Discount extension is negotiated for Catalog Lookup, a Business MAY
+return `discounts.available` in a `get_product` response. These entries are
+public promotion previews. They allow a Platform to describe a potentially
+applicable offer before the buyer creates a Cart or Checkout.
+
+Catalog previews are advisory. Cart or Checkout evaluation is authoritative for
+eligibility, application, calculated amounts, and allocations. When a Business
+returns `conditions`, a Platform MUST present them and MUST NOT represent a
+preview as a final eligibility decision.
+
+Catalog Lookup's existing `selected`, `filters`, `context`, `signals`,
+`attribution`, and `actions` semantics remain unchanged. A Business MAY use the
+existing request context to determine which public previews to return, but a
+Platform MUST NOT reuse a context-specific preview as a context-free eligibility
+decision. This extension does not define new request inputs or Action types.
+
+The Catalog composition applies only to `get_product` responses:
+
+- `lookup_catalog` requests and responses are unchanged.
+- `get_product` requests are unchanged.
+- `discounts.codes` and `discounts.applied` are not available in Catalog.
+- `applied` and `remaining_amount` are omitted from Catalog preview entries.
+- For a promotion with `type: "code"`, the Business discloses that an offer
+  exists but does not disclose the code itself.
+
+<!-- ucp:example schema=shopping/discount def=discount_get_product_response -->
+```json
+{
+  "ucp": {
+    "version": "{{ ucp_version }}"
+  },
+  "product": {
+    "id": "prod_jacket",
+    "title": "Unisex Jacket",
+    "description": { "plain": "A lightweight everyday jacket." },
+    "price_range": {
+      "min": { "amount": 7900, "currency": "USD" },
+      "max": { "amount": 7900, "currency": "USD" }
+    },
+    "variants": [
+      {
+        "id": "var_jacket_black",
+        "title": "Black",
+        "description": { "plain": "Black lightweight jacket." },
+        "price": { "amount": 7900, "currency": "USD" }
+      }
+    ]
+  },
+  "discounts": {
+    "available": [
+      {
+        "id": "promo_category_20",
+        "title": "20% off selected styles",
+        "type": "automatic",
+        "conditions": "Available on eligible styles for a limited time"
+      },
+      {
+        "id": "promo_member",
+        "title": "Member offer available",
+        "type": "code",
+        "conditions": "Eligible members can enter their offer code at checkout"
+      }
+    ]
+  }
+}
+```
+
 ## Allocation Details
 
 The `applied` array explains how discounts were calculated and distributed.
diff --git a/source/schemas/shopping/discount.json b/source/schemas/shopping/discount.json
index a0d48a74e..8a57c5cdf 100644
--- a/source/schemas/shopping/discount.json
+++ b/source/schemas/shopping/discount.json
@@ -3,7 +3,7 @@
   "$id": "https://ucp.dev/schemas/shopping/discount.json",
   "name": "dev.ucp.shopping.discount",
   "title": "Discount Extension",
-  "description": "Extends Cart and Checkout with discount support, including discount codes, automatic discounts, and eligibility-triggered provisional discounts.",
+  "description": "Extends Catalog Lookup, Cart, and Checkout with discount support, including discoverable promotions, discount codes, automatic discounts, and eligibility-triggered provisional discounts.",
   "$defs": {
     "allocation": {
       "type": "object",
@@ -79,6 +79,61 @@
         }
       }
     },
+    "available_discount": {
+      "type": "object",
+      "description": "A discount available for discovery in the current context.",
+      "required": [
+        "title",
+        "type"
+      ],
+      "properties": {
+        "id": {
+          "type": "string",
+          "description": "Stable discount identifier."
+        },
+        "title": {
+          "type": "string",
+          "description": "Human-readable promotion name (e.g., 'Summer Sale — 15% off')."
+        },
+        "type": {
+          "type": "string",
+          "enum": ["automatic", "code"],
+          "description": "'automatic' — business applies when conditions are met, no code needed. 'code' — buyer must submit a code (the code itself is NOT exposed)."
+        },
+        "conditions": {
+          "type": "string",
+          "description": "Human-readable summary of conditions to qualify (e.g., 'Orders over $50')."
+        },
+        "applied": {
+          "type": "boolean",
+          "description": "Whether this discount is already applied to the current cart/checkout."
+        },
+        "remaining_amount": {
+          "$ref": "../common/types/amount.json",
+          "description": "How much more the buyer needs to spend to qualify, in ISO 4217 minor units. Useful for 'add $12 more for free shipping' prompts."
+        }
+      }
+    },
+    "catalog_available_discount": {
+      "description": "A discoverable discount preview for a catalog product. Application state and cart-relative thresholds are not available in Catalog.",
+      "allOf": [
+        {
+          "$ref": "#/$defs/available_discount"
+        },
+        {
+          "not": {
+            "anyOf": [
+              {
+                "required": ["applied"]
+              },
+              {
+                "required": ["remaining_amount"]
+              }
+            ]
+          }
+        }
+      ]
+    },
     "discounts_object": {
       "type": "object",
       "description": "Discount codes input and applied discounts output.",
@@ -97,6 +152,60 @@
           },
           "description": "Discounts successfully applied (code-based and automatic).",
           "ucp_request": "omit"
+        },
+        "available": {
+          "type": "array",
+          "items": {
+            "$ref": "#/$defs/available_discount"
+          },
+          "description": "Discounts available for this cart or checkout context. Business-optional. Includes both automatic promotions and discoverable code-based offers.",
+          "ucp_request": "omit"
+        }
+      }
+    },
+    "catalog_discounts_object": {
+      "type": "object",
+      "description": "Publicly discoverable discounts for a catalog product detail response.",
+      "properties": {
+        "available": {
+          "type": "array",
+          "items": {
+            "$ref": "#/$defs/catalog_available_discount"
+          },
+          "description": "Promotions that may apply to the requested product. Cart or Checkout evaluation remains authoritative."
+        }
+      }
+    },
+    "discount_get_product_response": {
+      "allOf": [
+        {
+          "$ref": "catalog_lookup.json#/$defs/get_product_response"
+        },
+        {
+          "type": "object",
+          "properties": {
+            "discounts": {
+              "$ref": "#/$defs/catalog_discounts_object",
+              "ucp_request": "omit"
+            }
+          }
+        }
+      ]
+    },
+    "dev.ucp.shopping.catalog.lookup": {
+      "description": "Catalog Lookup composition with discoverable discounts on product detail responses.",
+      "$defs": {
+        "lookup_request": {
+          "$ref": "catalog_lookup.json#/$defs/lookup_request"
+        },
+        "lookup_response": {
+          "$ref": "catalog_lookup.json#/$defs/lookup_response"
+        },
+        "get_product_request": {
+          "$ref": "catalog_lookup.json#/$defs/get_product_request"
+        },
+        "get_product_response": {
+          "$ref": "#/$defs/discount_get_product_response"
         }
       }
     },