From 180c4c0eae5a61e62ce877173a9acd4254af4e59 Mon Sep 17 00:00:00 2001
From: VectorPeak <73048950+VectorPeak@users.noreply.github.com>
Date: Wed, 24 Jun 2026 15:22:57 +0800
Subject: [PATCH 1/2] .NET: Fix stop sequence array serialization

---
 .../ChatCompletions/Models/StopSequences.cs    |  2 +-
 .../OpenAIChatCompletionsSerializationTests.cs | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/ChatCompletions/Models/StopSequences.cs b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/ChatCompletions/Models/StopSequences.cs
index bed3b2a3206..3a97f2f19b0 100644
--- a/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/ChatCompletions/Models/StopSequences.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Hosting.OpenAI/ChatCompletions/Models/StopSequences.cs
@@ -183,7 +183,7 @@ public override void Write(Utf8JsonWriter writer, StopSequences? value, JsonSeri
         }
         else if (value.IsSequences)
         {
-            JsonSerializer.Serialize(writer, value.Sequences, ChatCompletionsJsonContext.Default.IReadOnlyListMessageContentPart);
+            JsonSerializer.Serialize(writer, value.Sequences, ChatCompletionsJsonContext.Default.IListString);
         }
         else
         {
diff --git a/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs b/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs
index edf11fbf6bb..a9f0b32507c 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs
@@ -54,6 +54,24 @@ public void Deserialize_BasicRequest_RoundTrip()
         Assert.Equal(request.Messages.Count, roundtripped.Messages.Count);
     }
 
+    [Fact]
+    public void Serialize_RequestWithMultipleStopSequences_WritesStringArray()
+    {
+        // Arrange
+        string originalJson = LoadChatCompletionsTraceFile("basic/request.json");
+        CreateChatCompletion request = JsonSerializer.Deserialize(originalJson, ChatCompletions.ChatCompletionsJsonContext.Default.CreateChatCompletion)!;
+        request.Stop = StopSequences.FromSequences(["END", "STOP"]);
+
+        // Act
+        string json = JsonSerializer.Serialize(request, ChatCompletions.ChatCompletionsJsonContext.Default.CreateChatCompletion);
+        using JsonDocument document = JsonDocument.Parse(json);
+
+        // Assert
+        JsonElement stop = document.RootElement.GetProperty("stop");
+        Assert.Equal(JsonValueKind.Array, stop.ValueKind);
+        Assert.Equal(["END", "STOP"], stop.EnumerateArray().Select(e => e.GetString()));
+    }
+
     [Fact]
     public void Deserialize_BasicRequest_HasMessages()
     {

From bc4cd11edb66b698b6291a13e5cbe3d299670cb8 Mon Sep 17 00:00:00 2001
From: VectorPeak <73048950+VectorPeak@users.noreply.github.com>
Date: Wed, 24 Jun 2026 17:18:10 +0800
Subject: [PATCH 2/2] Potential fix for pull request finding

Thanks

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
---
 .../OpenAIChatCompletionsSerializationTests.cs             | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs b/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs
index a9f0b32507c..86e9292d62b 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Hosting.OpenAI.UnitTests/OpenAIChatCompletionsSerializationTests.cs
@@ -67,9 +67,10 @@ public void Serialize_RequestWithMultipleStopSequences_WritesStringArray()
         using JsonDocument document = JsonDocument.Parse(json);
 
         // Assert
-        JsonElement stop = document.RootElement.GetProperty("stop");
-        Assert.Equal(JsonValueKind.Array, stop.ValueKind);
-        Assert.Equal(["END", "STOP"], stop.EnumerateArray().Select(e => e.GetString()));
+JsonElement stop = document.RootElement.GetProperty("stop");
+Assert.Equal(JsonValueKind.Array, stop.ValueKind);
+string[] stopValues = stop.EnumerateArray().Select(static e => e.GetString()!).ToArray();
+Assert.Equal(["END", "STOP"], stopValues);
     }
 
     [Fact]