diff --git a/src/messaging/dotnet/src/Core/Protocol/Json/ThrowHelper.cs b/src/messaging/dotnet/src/Core/Protocol/Json/ThrowHelper.cs
index 317b83e6a..da8abbf23 100644
--- a/src/messaging/dotnet/src/Core/Protocol/Json/ThrowHelper.cs
+++ b/src/messaging/dotnet/src/Core/Protocol/Json/ThrowHelper.cs
@@ -10,11 +10,13 @@
 // or implied. See the License for the specific language governing permissions
 // and limitations under the License.
 
+using System.Text.Json;
+
 namespace MorganStanley.ComposeUI.Messaging.Protocol.Json;
 
 internal static class ThrowHelper
 {
-    public static InvalidOperationException StringExpected() => new InvalidOperationException("String expected");
+    public static InvalidOperationException StringExpected(JsonTokenType actualTokenType) => new InvalidOperationException($"String expected (actual: {actualTokenType})");
 
     public static ArgumentException DestinationTooShort(string paramName) =>
         new ArgumentException("The destination buffer is too short", paramName);
diff --git a/src/messaging/dotnet/src/Core/Protocol/Json/Utf8JsonReaderExtensions.cs b/src/messaging/dotnet/src/Core/Protocol/Json/Utf8JsonReaderExtensions.cs
index 4e13322cf..6d69a77dd 100644
--- a/src/messaging/dotnet/src/Core/Protocol/Json/Utf8JsonReaderExtensions.cs
+++ b/src/messaging/dotnet/src/Core/Protocol/Json/Utf8JsonReaderExtensions.cs
@@ -44,7 +44,7 @@ public static int CopyString(this ref Utf8JsonReader reader, Span<byte> utf8Dest
     {
         if (reader.TokenType is not (JsonTokenType.String or JsonTokenType.PropertyName))
         {
-            throw ThrowHelper.StringExpected();
+            throw ThrowHelper.StringExpected(reader.TokenType);
         }
 
         var valueLength = reader.HasValueSequence 
diff --git a/src/messaging/dotnet/test/Core.Tests/Protocol/Json/Utf8JsonReaderExtensions.Tests.cs b/src/messaging/dotnet/test/Core.Tests/Protocol/Json/Utf8JsonReaderExtensions.Tests.cs
index 1df838170..703a00d90 100644
--- a/src/messaging/dotnet/test/Core.Tests/Protocol/Json/Utf8JsonReaderExtensions.Tests.cs
+++ b/src/messaging/dotnet/test/Core.Tests/Protocol/Json/Utf8JsonReaderExtensions.Tests.cs
@@ -20,7 +20,7 @@ namespace MorganStanley.ComposeUI.Messaging.Protocol.Json;
 
 public class Utf8JsonReaderExtensionsTests
 {
-    [Theory(Skip ="ci fail")]
+    [Theory]
     [ClassData(typeof(CopyStringTheoryData))]
     public void CopyString_writes_the_unescaped_UTF8_string_to_the_buffer(CopyStringTestData testData)
     {
@@ -55,10 +55,10 @@ public Utf8JsonReader CreateReader()
                 reader = new Utf8JsonReader(MemoryHelper.CreateMultipartSequence(_utf8Buffers));
             }
 
-            Debug.Assert(reader.Read());
-            Debug.Assert(reader.TokenType == JsonTokenType.StartArray);
-            Debug.Assert(reader.Read());
-            Debug.Assert(reader.TokenType == JsonTokenType.String);
+            reader.Read().Should().Be(true);
+            reader.TokenType.Should().Be(JsonTokenType.StartArray);
+            reader.Read().Should().Be(true);
+            reader.TokenType.Should().Be(JsonTokenType.String);
 
             return reader;
         }