diff --git a/src/AnthropicClient/AnthropicApiClient.cs b/src/AnthropicClient/AnthropicApiClient.cs
index 2c57cdd..7ec3b10 100644
--- a/src/AnthropicClient/AnthropicApiClient.cs
+++ b/src/AnthropicClient/AnthropicApiClient.cs
@@ -275,8 +275,9 @@ public class AnthropicApiClient : IAnthropicApiClient
   }
 
   private async Task<HttpResponseMessage> SendRequestAsync(BaseMessageRequest request)
-  {
-    var requestContent = new StringContent(Serialize(request), Encoding.UTF8, JsonContentType);
+  { 
+    var requestJson = Serialize(request);
+    var requestContent = new StringContent(requestJson, Encoding.UTF8, JsonContentType);
     return await _httpClient.PostAsync(MessagesEndpoint, requestContent);
   }