diff --git a/source/schemas/common/types/measure.json b/source/schemas/common/types/measure.json
new file mode 100644
index 000000000..4d67ce7e5
--- /dev/null
+++ b/source/schemas/common/types/measure.json
@@ -0,0 +1,19 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://ucp.dev/schemas/common/types/measure.json",
+  "title": "Measure",
+  "description": "Represents a quantitative value paired with its physical or standardized unit of measurement.",
+  "type": "object",
+  "additionalProperties": true,
+  "required": ["value", "unit"],
+  "properties": {
+    "value": {
+      "type": "number",
+      "description": "Precise fractional quantity."
+    },
+    "unit": {
+      "type": "string",
+      "description": "Unit of measurement. MUST use 'each' to represent countable goods and SHOULD prefer using standard symbol (e.g., kg for kilogram, lb for pound) for other units."
+    }
+  }
+}
diff --git a/source/schemas/shopping/types/adjustment.json b/source/schemas/shopping/types/adjustment.json
index c4fa91fbd..3f9cbdd50 100644
--- a/source/schemas/shopping/types/adjustment.json
+++ b/source/schemas/shopping/types/adjustment.json
@@ -44,8 +44,16 @@
             "description": "Line item ID reference."
           },
           "quantity": {
-            "type": "integer",
-            "description": "Signed quantity affected by this adjustment. Negative values represent reductions (e.g. returns); positive values represent additions (e.g. exchanges)."
+            "anyOf": [
+              {
+                "type": "integer",
+                "description": "Signed quantity affected by this adjustment. Negative values represent reductions (e.g. returns); positive values represent additions (e.g. exchanges)."
+              },
+              {
+                "$ref": "../../common/types/measure.json",
+                "description": "The precise signed fractional quantity and unit of the item affected by this adjustment. Negative values represent reductions (e.g. returns); positive values represent additions (e.g. exchanges)."
+              }
+            ]
           }
         }
       },
diff --git a/source/schemas/shopping/types/expectation.json b/source/schemas/shopping/types/expectation.json
index ccd01c8e9..314d5dd62 100644
--- a/source/schemas/shopping/types/expectation.json
+++ b/source/schemas/shopping/types/expectation.json
@@ -26,9 +26,20 @@
             "description": "Line item ID reference."
           },
           "quantity": {
-            "type": "integer",
-            "minimum": 1,
-            "description": "Quantity of this item in this expectation."
+            "anyOf": [
+              {
+                "type": "integer",
+                "minimum": 1,
+                "description": "Quantity of this item in this expectation."
+              },
+              {
+                "$ref": "../../common/types/measure.json",
+                "properties": {
+                  "value": { "exclusiveMinimum": 0 }
+                },
+                "description": "The precise fractional quantity and unit of the item in this expectation."
+              }
+            ]
           }
         }
       },
diff --git a/source/schemas/shopping/types/fulfillment_event.json b/source/schemas/shopping/types/fulfillment_event.json
index 5d0ba7e7f..fab60625a 100644
--- a/source/schemas/shopping/types/fulfillment_event.json
+++ b/source/schemas/shopping/types/fulfillment_event.json
@@ -35,9 +35,20 @@
             "description": "Line item ID reference."
           },
           "quantity": {
-            "type": "integer",
-            "minimum": 1,
-            "description": "Quantity fulfilled in this event."
+            "anyOf": [
+              {
+                "type": "integer",
+                "minimum": 1,
+                "description": "Quantity fulfilled in this event."
+              },
+              {
+                "$ref": "../../common/types/measure.json",
+                "properties": {
+                  "value": { "exclusiveMinimum": 0 }
+                },
+                "description": "The precise fractional quantity and unit of the item in this event."
+              }
+            ]
           }
         }
       },
diff --git a/source/schemas/shopping/types/line_item.json b/source/schemas/shopping/types/line_item.json
index 0eba9ed05..7d0e269fa 100644
--- a/source/schemas/shopping/types/line_item.json
+++ b/source/schemas/shopping/types/line_item.json
@@ -22,9 +22,20 @@
       "$ref": "item.json"
     },
     "quantity": {
-      "type": "integer",
-      "description": "Quantity of the item being purchased.",
-      "minimum": 1
+      "anyOf": [
+        {
+          "type": "integer",
+          "description": "Quantity of the item being purchased.",
+          "minimum": 1
+        },
+        {
+          "$ref": "../../common/types/measure.json",
+          "properties": {
+            "value": { "exclusiveMinimum": 0 }
+          },
+          "description": "The precise fractional quantity and unit of the item being purchased."
+        }
+      ]
     },
     "totals": {
       "type": "array",
diff --git a/source/schemas/shopping/types/order_line_item.json b/source/schemas/shopping/types/order_line_item.json
index 5f639dcff..c851e1469 100644
--- a/source/schemas/shopping/types/order_line_item.json
+++ b/source/schemas/shopping/types/order_line_item.json
@@ -20,26 +20,58 @@
       "description": "Product data (id, title, price, image_url)."
     },
     "quantity": {
-      "type": "object",
-      "required": ["total", "fulfilled"],
-      "properties": {
-        "original": {
-          "type": "integer",
-          "minimum": 0,
-          "description": "Quantity from the original checkout."
+      "anyOf": [
+        {
+          "type": "object",
+          "required": ["total", "fulfilled"],
+          "properties": {
+            "original": {
+              "type": "integer",
+              "minimum": 0,
+              "description": "Quantity from the original checkout."
+            },
+            "total": {
+              "type": "integer",
+              "minimum": 0,
+              "description": "Current total active quantity. May differ from original due to post-order modifications (e.g., returns or cancellations)."
+            },
+            "fulfilled": {
+              "type": "integer",
+              "minimum": 0,
+              "description": "Quantity fulfilled so far."
+            }
+          },
+          "description": "Quantity tracking for the line item."
         },
-        "total": {
-          "type": "integer",
-          "minimum": 0,
-          "description": "Current total active quantity. May differ from original due to post-order modifications (e.g., returns or cancellations)."
-        },
-        "fulfilled": {
-          "type": "integer",
-          "minimum": 0,
-          "description": "Quantity fulfilled so far."
+        {
+          "type": "object",
+          "required": ["total", "fulfilled"],
+          "properties": {
+            "original": {
+              "$ref": "../../common/types/measure.json",
+              "properties": {
+                "value": { "minimum": 0 }
+              },
+              "description": "The fractional quantity and unit of the item in the original checkout."
+            },
+            "total": {
+              "$ref": "../../common/types/measure.json",
+              "properties": {
+                "value": { "minimum": 0 }
+              },
+              "description": "Current total active fractional quantity. May differ from original due to post-order modifications (e.g., returns or cancellations)."
+            },
+            "fulfilled": {
+              "$ref": "../../common/types/measure.json",
+              "properties": {
+                "value": { "minimum": 0 }
+              },
+              "description": "Fractional quantity fulfilled so far."
+            }
+          },
+          "description": "Precise fractional tracking for the line item."
         }
-      },
-      "description": "Quantity tracking for the line item."
+      ]
     },
     "totals": {
       "type": "array",
diff --git a/source/schemas/shopping/types/product.json b/source/schemas/shopping/types/product.json
index 95c4fbdf8..40de390b7 100644
--- a/source/schemas/shopping/types/product.json
+++ b/source/schemas/shopping/types/product.json
@@ -79,7 +79,7 @@
       "items": {
         "type": "string"
       },
-      "description": "Product tags for categorization and search."
+      "description": "Product tags for categorization, search, and compliance rules (e.g., restricted goods)."
     },
     "metadata": {
       "type": "object",
diff --git a/source/schemas/shopping/types/variant.json b/source/schemas/shopping/types/variant.json
index 9355b5f1a..efe00f1c6 100644
--- a/source/schemas/shopping/types/variant.json
+++ b/source/schemas/shopping/types/variant.json
@@ -84,13 +84,8 @@
           "description": "ISO 4217 currency code."
         },
         "measure": {
-          "type": "object",
-          "description": "Product quantity in packaging (e.g., 750ml bottle).",
-          "required": ["value", "unit"],
-          "properties": {
-            "value": { "type": "number", "description": "Package quantity." },
-            "unit": { "type": "string", "description": "Unit of measurement." }
-          }
+          "$ref": "../../common/types/measure.json",
+          "description": "Product quantity in packaging (e.g., 750ml bottle)."
         },
         "reference": {
           "type": "object",