.NET: Fix message ordering inconsistency when using AIContextProvider

dotnet/src/Microsoft.Agents.AI/ChatClient/ChatClientAgent.cs

@@ -647,6 +647,9 @@ await thread.AIContextProvider.InvokedAsync(new(inputMessages, aiContextProvider
                 inputMessagesForChatClient.AddRange(await typedThread.MessageStore.GetMessagesAsync(cancellationToken).ConfigureAwait(false));
             }
 
+            // Add the input messages before getting context from AIContextProvider.
+            inputMessagesForChatClient.AddRange(inputMessages);
+
             // If we have an AIContextProvider, we should get context from it, and update our
             // messages and options with the additional context.
             if (typedThread.AIContextProvider is not null)
@@ -675,9 +678,6 @@ await thread.AIContextProvider.InvokedAsync(new(inputMessages, aiContextProvider
                     chatOptions.Instructions = string.IsNullOrWhiteSpace(chatOptions.Instructions) ? aiContext.Instructions : $"{chatOptions.Instructions}\n{aiContext.Instructions}";
                 }
             }
-
-            // Add the input messages to the end of thread messages.
-            inputMessagesForChatClient.AddRange(inputMessages);
         }
 
         // If a user provided two different thread ids, via the thread object and options, we should throw

dotnet/tests/Microsoft.Agents.AI.UnitTests/ChatClient/ChatClientAgentTests.cs

@@ -599,13 +599,13 @@ public async Task RunAsyncInvokesAIContextProviderAndUsesResultAsync()
         await agent.RunAsync(requestMessages, thread);
 
         // Assert
-        // Should contain: base instructions, context message, user message, base function, context function
+        // Should contain: base instructions, user message, context message, base function, context function
         Assert.Equal(2, capturedMessages.Count);
         Assert.Equal("base instructions\ncontext provider instructions", capturedInstructions);
-        Assert.Equal("context provider message", capturedMessages[0].Text);
-        Assert.Equal(ChatRole.System, capturedMessages[0].Role);
-        Assert.Equal("user message", capturedMessages[1].Text);
-        Assert.Equal(ChatRole.User, capturedMessages[1].Role);
+        Assert.Equal("user message", capturedMessages[0].Text);
+        Assert.Equal(ChatRole.User, capturedMessages[0].Role);
+        Assert.Equal("context provider message", capturedMessages[1].Text);
+        Assert.Equal(ChatRole.System, capturedMessages[1].Role);
         Assert.Equal(2, capturedTools.Count);
         Assert.Contains(capturedTools, t => t.Name == "base function");
         Assert.Contains(capturedTools, t => t.Name == "context provider function");
@@ -2056,13 +2056,13 @@ public async Task RunStreamingAsyncInvokesAIContextProviderAndUsesResultAsync()
         _ = await updates.ToAgentRunResponseAsync();
 
         // Assert
-        // Should contain: base instructions, context message, user message, base function, context function
+        // Should contain: base instructions, user message, context message, base function, context function
         Assert.Equal(2, capturedMessages.Count);
         Assert.Equal("base instructions\ncontext provider instructions", capturedInstructions);
-        Assert.Equal("context provider message", capturedMessages[0].Text);
-        Assert.Equal(ChatRole.System, capturedMessages[0].Role);
-        Assert.Equal("user message", capturedMessages[1].Text);
-        Assert.Equal(ChatRole.User, capturedMessages[1].Role);
+        Assert.Equal("user message", capturedMessages[0].Text);
+        Assert.Equal(ChatRole.User, capturedMessages[0].Role);
+        Assert.Equal("context provider message", capturedMessages[1].Text);
+        Assert.Equal(ChatRole.System, capturedMessages[1].Role);
         Assert.Equal(2, capturedTools.Count);
         Assert.Contains(capturedTools, t => t.Name == "base function");
         Assert.Contains(capturedTools, t => t.Name == "context provider function");