dotnet · Copilot · May 5, 2026 · May 5, 2026 · May 5, 2026 · May 5, 2026
diff --git a/NuGet.config b/NuGet.config
@@ -17,6 +17,8 @@
     <add key="dotnet9-transport" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet9-transport/nuget/v3/index.json" />
     <!-- Used for the Rich Navigation indexing task -->
     <add key="richnav" value="https://pkgs.dev.azure.com/azure-public/vside/_packaging/vs-buildservices/nuget/v3/index.json" />
+    <!-- Used for pre-release OpenAI SDK packages; can be removed once a stable release is published -->
+    <add key="github-openai" value="https://nuget.pkg.github.com/openai/index.json" />
   </packageSources>
   <!-- Define mappings by adding package patterns beneath the target source.
        https://aka.ms/nuget-package-source-mapping  -->
@@ -39,6 +41,10 @@
     <packageSource key="richnav">
       <package pattern="*" />
     </packageSource>
+    <packageSource key="github-openai">
+      <package pattern="OpenAI" />
+      <package pattern="OpenAI.Responses" />
+    </packageSource>
   </packageSourceMapping>
   <disabledPackageSources>
     <!--Begin: Package sources managed by Dependency Flow automation. Do not edit the sources below.-->

@@ -17,7 +17,7 @@
     <PackageVersion Include="Microsoft.Extensions.VectorData.Abstractions" Version="$(MicrosoftExtensionsVectorDataAbstractionsVersion)" />
     <PackageVersion Include="Microsoft.ML.Tokenizers" Version="$(MicrosoftMLTokenizersVersion)" />
     <PackageVersion Include="ModelContextProtocol.Core" Version="1.2.0" />
-    <PackageVersion Include="OpenAI" Version="2.10.0" />
+    <PackageVersion Include="OpenAI" Version="2.10.0-alpha.703" />
     <PackageVersion Include="Polly" Version="8.4.2" />
     <PackageVersion Include="Polly.Core" Version="8.4.2" />
     <PackageVersion Include="Polly.Extensions" Version="8.4.2" />

@@ -17,7 +17,6 @@
 using System.Threading.Tasks;
 using Microsoft.Shared.DiagnosticIds;
 using Microsoft.Shared.Diagnostics;
-using OpenAI;
 using OpenAI.Responses;
 
 #pragma warning disable S1226 // Method parameters, caught exceptions and foreach variables' initial values should not be ignored
@@ -464,6 +463,7 @@ ChatResponseUpdate CreateUpdate(AIContent? content = null) =>
 
                         case FunctionCallResponseItem fcri:
                             anyFunctions = true;
+                            lastMessageId = outputItemAddedUpdate.Item.Id;
                             lastRole = ChatRole.Assistant;
                             break;
                     }
@@ -735,7 +735,9 @@ private static bool IsStoredOutputDisabled(CreateResponseOptions? options, Respo
             case HostedToolSearchTool:
                 // Workaround: The OpenAI .NET SDK doesn't yet expose a ToolSearchTool type.
                 // See https://github.com/openai/openai-dotnet/issues/1053
-                return ModelReaderWriter.Read<ResponseTool>(BinaryData.FromString("""{"type": "tool_search"}"""), ModelReaderWriterOptions.Json, OpenAIContext.Default)!;
+#pragma warning disable OPENAI001 // OpenAIResponsesContext is experimental
+                return ModelReaderWriter.Read<ResponseTool>(BinaryData.FromString("""{"type": "tool_search"}"""), ModelReaderWriterOptions.Json, OpenAIResponsesContext.Default)!;
+#pragma warning restore OPENAI001
 
             case HostedWebSearchTool webSearchTool:
                 return new WebSearchTool
@@ -895,7 +897,9 @@ internal static ResponseTool ToNamespaceResponseTool(string name, string? descri
             writer.WriteStartArray("tools"u8);
             foreach (var namespacedTool in namespacedTools)
             {
-                var toolData = ModelReaderWriter.Write(namespacedTool, ModelReaderWriterOptions.Json, OpenAIContext.Default);
+#pragma warning disable OPENAI001 // OpenAIResponsesContext is experimental
+                var toolData = ModelReaderWriter.Write(namespacedTool, ModelReaderWriterOptions.Json, OpenAIResponsesContext.Default);
+#pragma warning restore OPENAI001
                 using var doc = JsonDocument.Parse(toolData);
                 doc.RootElement.WriteTo(writer);
             }
@@ -904,7 +908,9 @@ internal static ResponseTool ToNamespaceResponseTool(string name, string? descri
             writer.WriteEndObject();
         }
 
-        return ModelReaderWriter.Read<ResponseTool>(BinaryData.FromBytes(stream.ToArray()), ModelReaderWriterOptions.Json, OpenAIContext.Default)!;
+#pragma warning disable OPENAI001 // OpenAIResponsesContext is experimental
+        return ModelReaderWriter.Read<ResponseTool>(BinaryData.FromBytes(stream.ToArray()), ModelReaderWriterOptions.Json, OpenAIResponsesContext.Default)!;
+#pragma warning restore OPENAI001
     }
 
     /// <summary>Creates a <see cref="ChatRole"/> from a <see cref="MessageRole"/>.</summary>

@@ -5974,6 +5974,7 @@ public async Task StreamingResponseWithFunctionCallOutput_YieldsFunctionResultCo
         var functionCallUpdate = updates.FirstOrDefault(u => u.Contents.OfType<FunctionCallContent>().Any());
         Assert.NotNull(functionCallUpdate);
         Assert.Equal(ChatRole.Assistant, functionCallUpdate.Role);
+        Assert.Equal("fc_001", functionCallUpdate.MessageId); // Verify MessageID is set for function calls (issue #7479)
         var fcc = functionCallUpdate.Contents.OfType<FunctionCallContent>().Single();
         Assert.Equal("call_123", fcc.CallId);
         Assert.Equal("get_weather", fcc.Name);
@@ -5994,14 +5995,23 @@ public async Task StreamingResponseWithFunctionCallOutput_YieldsFunctionResultCo
         var response = updates.ToChatResponse();
         Assert.Equal("resp_001", response.ResponseId);
         Assert.Equal("gpt-4o-mini", response.ModelId);
-        Assert.Single(response.Messages);
-        var message = response.Messages[0];
-        Assert.Equal(ChatRole.Assistant, message.Role);
 
-        // Message should contain: FunctionCallContent, FunctionResultContent, and TextContent
-        Assert.Single(message.Contents.OfType<FunctionCallContent>());
-        Assert.Single(message.Contents.OfType<FunctionResultContent>());
-        var textContent = Assert.Single(message.Contents.OfType<TextContent>());
+        // With the MessageID fix, function calls now have their own MessageId ("fc_001") and
+        // the text message has a different MessageId ("msg_001"), resulting in 2 separate messages.
+        Assert.Equal(2, response.Messages.Count);
+
+        // First message contains the function call and result items (MessageId="fc_001")
+        var functionMessage = response.Messages[0];
+        Assert.Equal(ChatRole.Assistant, functionMessage.Role);
+        Assert.Equal("fc_001", functionMessage.MessageId);
+        Assert.Single(functionMessage.Contents.OfType<FunctionCallContent>());
+        Assert.Single(functionMessage.Contents.OfType<FunctionResultContent>());
+
+        // Second message contains the text response (MessageId="msg_001")
+        var textMessage = response.Messages[1];
+        Assert.Equal(ChatRole.Assistant, textMessage.Role);
+        Assert.Equal("msg_001", textMessage.MessageId);
+        var textContent = Assert.Single(textMessage.Contents.OfType<TextContent>());
         Assert.Equal("It's 25°C and sunny in Paris.", textContent.Text);
 
         // Verify usage