From 4d040086b11aa6c98c5323147a7a2507e75a4d4d Mon Sep 17 00:00:00 2001
From: Justintime50 <39606064+Justintime50@users.noreply.github.com>
Date: Tue, 3 Feb 2026 16:21:36 -0700
Subject: [PATCH] fix: correct usage of line items shipment property (closes
 #645)

---
 EasyPost/Models/API/LineItem.cs        | 27 ++++++++++++++++++++++++++
 EasyPost/Models/API/Shipment.cs        |  6 ++++++
 EasyPost/Parameters/IParameter.cs      |  7 +++++++
 EasyPost/Parameters/Shipment/Create.cs | 20 ++-----------------
 4 files changed, 42 insertions(+), 18 deletions(-)
 create mode 100644 EasyPost/Models/API/LineItem.cs

diff --git a/EasyPost/Models/API/LineItem.cs b/EasyPost/Models/API/LineItem.cs
new file mode 100644
index 000000000..e49ebe83c
--- /dev/null
+++ b/EasyPost/Models/API/LineItem.cs
@@ -0,0 +1,27 @@
+using EasyPost._base;
+using Newtonsoft.Json;
+
+namespace EasyPost.Models.API
+{
+    /// <summary>
+    ///     Class representing line items of a <a href="https://docs.easypost.com/docs/shipments">Shipment</a>.
+    /// </summary>
+    public class LineItem : EasyPostObject, Parameters.ILineItemParameter
+    {
+        #region JSON Properties
+
+        /// <summary>
+        ///     The total value of the line item.
+        /// </summary>
+        [JsonProperty("total_line_value")]
+        public string? TotalLineValue { get; set; }
+
+        /// <summary>
+        ///     The description of the item.
+        /// </summary>
+        [JsonProperty("item_description")]
+        public string? ItemDescription { get; set; }
+
+        #endregion
+    }
+}
diff --git a/EasyPost/Models/API/Shipment.cs b/EasyPost/Models/API/Shipment.cs
index 800ea17c2..7711819a2 100644
--- a/EasyPost/Models/API/Shipment.cs
+++ b/EasyPost/Models/API/Shipment.cs
@@ -77,6 +77,12 @@ public class Shipment : EasyPostObject, Parameters.IShipmentParameter
         [JsonProperty("is_return")]
         public bool? IsReturn { get; set; }
 
+        /// <summary>
+        ///     A list of <see cref="LineItem"/>s associated with the shipment.
+        /// </summary>
+        [JsonProperty("line_items")]
+        public List<LineItem>? LineItems { get; set; }
+
         /// <summary>
         ///     A list of any carrier errors that occurred during rating or purchasing.
         /// </summary>
diff --git a/EasyPost/Parameters/IParameter.cs b/EasyPost/Parameters/IParameter.cs
index 451f84900..ccca58f0f 100644
--- a/EasyPost/Parameters/IParameter.cs
+++ b/EasyPost/Parameters/IParameter.cs
@@ -63,6 +63,13 @@ public interface IInsuranceParameter : IParameter
     {
     }
 
+    /// <summary>
+    ///     An interface marking that an instance of the implementing class can be used as a line item parameter in a Parameters object.
+    /// </summary>
+    public interface ILineItemParameter : IParameter
+    {
+    }
+
     /// <summary>
     ///     An interface marking that an instance of the implementing class can be used as an order parameter in a Parameters object.
     /// </summary>
diff --git a/EasyPost/Parameters/Shipment/Create.cs b/EasyPost/Parameters/Shipment/Create.cs
index 8ca6b6353..0f3a1e4bc 100644
--- a/EasyPost/Parameters/Shipment/Create.cs
+++ b/EasyPost/Parameters/Shipment/Create.cs
@@ -155,27 +155,11 @@ public class Create : BaseParameters<Models.API.Shipment>, IShipmentParameter
         public List<string>? CarrierAccountIds { get; set; }
 
         /// <summary>
-        ///     A list of line items for the new <see cref="Models.API.Shipment"/>.
+        ///     A list of <see cref="Models.API.LineItem"/>s for the new <see cref="Models.API.Shipment"/>.
         /// </summary>
         [TopLevelRequestParameter(Necessity.Optional, "shipment", "line_items")]
         [NestedRequestParameter(typeof(Order.Create), Necessity.Optional, "line_items")]
-        public List<LineItem>? LineItems { get; set; }
-
-        /// <summary>
-        ///     Represents a line item for a shipment.
-        /// </summary>
-        public class LineItem
-        {
-            /// <summary>
-            ///     The total value of the line item.
-            /// </summary>
-            public string? TotalLineValue { get; set; }
-
-            /// <summary>
-            ///     The description of the item.
-            /// </summary>
-            public string? ItemDescription { get; set; }
-        }
+        public List<ILineItemParameter>? LineItems { get; set; }
 
         #endregion
     }