From b82d073d76740a485641db917da60e182dfdffc2 Mon Sep 17 00:00:00 2001
From: "Ram.Type-0" <39725073+RamType0@users.noreply.github.com>
Date: Wed, 5 Feb 2025 11:36:19 +0900
Subject: [PATCH 1/3] Fix #10389

Use `JsonSerializerOptions.Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping`
---
 .../AI/FunctionCalling/FunctionCallsProcessor.cs           | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs b/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs
index 5fe03ebb925d..d050156a431c 100644
--- a/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs
+++ b/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs
@@ -5,6 +5,7 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using System.Text.Encodings.Web;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -490,6 +491,10 @@ public static string ProcessFunctionResult(object functionResult)
             return chatMessageContent.ToString();
         }
 
-        return JsonSerializer.Serialize(functionResult);
+        return JsonSerializer.Serialize(functionResult, s_functionResultSerializerOptions);
     }
+    private static readonly JsonSerializerOptions s_functionResultSerializerOptions = new()
+    {
+        Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
+    };
 }

From d5ac12adb05d1d55927bd26a4e9ec0f74b825c2a Mon Sep 17 00:00:00 2001
From: "Ram.Type-0" <39725073+RamType0@users.noreply.github.com>
Date: Wed, 5 Feb 2025 11:52:50 +0900
Subject: [PATCH 2/3] Add some documents to private field

---
 .../AI/FunctionCalling/FunctionCallsProcessor.cs           | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs b/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs
index d050156a431c..e1d3685238e5 100644
--- a/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs
+++ b/dotnet/src/InternalUtilities/connectors/AI/FunctionCalling/FunctionCallsProcessor.cs
@@ -493,6 +493,13 @@ public static string ProcessFunctionResult(object functionResult)
 
         return JsonSerializer.Serialize(functionResult, s_functionResultSerializerOptions);
     }
+
+    /// <summary>
+    /// The <see cref="JsonSerializerOptions" /> which will be used in <see cref="ProcessFunctionResult(object)"/>.
+    /// </summary>
+    /// <remarks>
+    /// <see cref="JsonSerializer.Serialize{TValue}(TValue, JsonSerializerOptions?)"/> is very likely to escape characters and generates LLM unfriendly results by default.
+    /// </remarks>
     private static readonly JsonSerializerOptions s_functionResultSerializerOptions = new()
     {
         Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping,

From 035d1ae7f951ef951a0080037660a5b56f14a7e5 Mon Sep 17 00:00:00 2001
From: "Ram.Type-0" <p0211@live.jp>
Date: Sat, 8 Feb 2025 03:02:30 +0900
Subject: [PATCH 3/3] Add tests

---
 .../AIConnectors/FunctionCallsProcessorTests.cs     | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/dotnet/src/SemanticKernel.UnitTests/Utilities/AIConnectors/FunctionCallsProcessorTests.cs b/dotnet/src/SemanticKernel.UnitTests/Utilities/AIConnectors/FunctionCallsProcessorTests.cs
index 6f0b40f8e82d..c6559f1eac0f 100644
--- a/dotnet/src/SemanticKernel.UnitTests/Utilities/AIConnectors/FunctionCallsProcessorTests.cs
+++ b/dotnet/src/SemanticKernel.UnitTests/Utilities/AIConnectors/FunctionCallsProcessorTests.cs
@@ -824,6 +824,19 @@ public void ItShouldSerializeFunctionResultsOfComplexType()
         Assert.Equal("{\"a\":2,\"b\":\"test\"}", result);
     }
 
+    [Fact]
+    public void ItShouldSerializeFunctionResultsWithStringProperties()
+    {
+        // Arrange
+        var functionResult = new { Text = "ﾃｽﾄ" };
+
+        // Act
+        var result = FunctionCallsProcessor.ProcessFunctionResult(functionResult);
+
+        // Assert
+        Assert.Equal("{\"Text\":\"ﾃｽﾄ\"}", result);
+    }
+
     private sealed class AutoFunctionInvocationFilter(
         Func<AutoFunctionInvocationContext, Func<AutoFunctionInvocationContext, Task>, Task>? onAutoFunctionInvocation) : IAutoFunctionInvocationFilter
     {