diff --git a/Anthropic.SDK.Tests/Anthropic.SDK.Tests.csproj b/Anthropic.SDK.Tests/Anthropic.SDK.Tests.csproj
index 41cb29e..88a5407 100644
--- a/Anthropic.SDK.Tests/Anthropic.SDK.Tests.csproj
+++ b/Anthropic.SDK.Tests/Anthropic.SDK.Tests.csproj
@@ -22,12 +22,12 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="8.0.0" />
-    <PackageReference Include="Microsoft.Extensions.AI" Version="9.0.1-preview.1.24570.5" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.1.0" />
-    <PackageReference Include="Microsoft.SemanticKernel" Version="1.30.0" />
-    <PackageReference Include="Microsoft.SemanticKernel.Abstractions" Version="1.30.0" />
-    <PackageReference Include="MSTest.TestAdapter" Version="2.2.8" />
-    <PackageReference Include="MSTest.TestFramework" Version="2.2.8" />
+    <PackageReference Include="Microsoft.Extensions.AI" Version="9.1.0-preview.1.25064.3" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="Microsoft.SemanticKernel" Version="1.33.0" />
+    <PackageReference Include="Microsoft.SemanticKernel.Abstractions" Version="1.33.0" />
+    <PackageReference Include="MSTest.TestAdapter" Version="3.7.1" />
+    <PackageReference Include="MSTest.TestFramework" Version="3.7.1" />
     <PackageReference Include="coverlet.collector" Version="3.1.2" />
   </ItemGroup>
 
diff --git a/Anthropic.SDK/Anthropic.SDK.csproj b/Anthropic.SDK/Anthropic.SDK.csproj
index 38c63f4..0130598 100644
--- a/Anthropic.SDK/Anthropic.SDK.csproj
+++ b/Anthropic.SDK/Anthropic.SDK.csproj
@@ -34,7 +34,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.0.1-preview.1.24570.5" />
+    <PackageReference Include="Microsoft.Extensions.AI.Abstractions" Version="9.1.0-preview.1.25064.3" />
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="8.0.0" />
   </ItemGroup>
 
diff --git a/Anthropic.SDK/Messaging/MessagesEndpoint.ChatClient.cs b/Anthropic.SDK/Messaging/MessagesEndpoint.ChatClient.cs
index 923de97..b0799f7 100644
--- a/Anthropic.SDK/Messaging/MessagesEndpoint.ChatClient.cs
+++ b/Anthropic.SDK/Messaging/MessagesEndpoint.ChatClient.cs
@@ -95,7 +95,7 @@ private static UsageDetails CreateUsageDetails(Usage usage) =>
         {
             InputTokenCount = usage.InputTokens,
             OutputTokenCount = usage.OutputTokens,
-            AdditionalProperties = new()
+            AdditionalCounts = new()
             {
                 [nameof(usage.CacheCreationInputTokens)] = usage.CacheCreationInputTokens,
                 [nameof(usage.CacheReadInputTokens)] = usage.CacheReadInputTokens,