Merge branch 'main' into crickman/dotnet-sample-improvements

dotnet/samples/GettingStarted/Agents/Agent_Step14_Middleware/Program.cs

@@ -2,8 +2,9 @@
 
 // This sample shows multiple middleware layers working together with Azure OpenAI:
 // chat client (global/per-request), agent run (PII filtering and guardrails),
-// function invocation (logging and result overrides), and human-in-the-loop
-// approval workflows for sensitive function calls.
+// function invocation (logging and result overrides), human-in-the-loop
+// approval workflows for sensitive function calls, and MessageAIContextProvider
+// middleware for injecting additional context messages into the agent pipeline.
 
 using System.ComponentModel;
 using System.Text.RegularExpressions;
@@ -96,6 +97,20 @@ var response = await originalAgent // Using per-request middleware pipeline with
 
 Console.WriteLine($"Per-request middleware response: {response}");
 
+// MessageAIContextProvider middleware that injects additional messages into the agent request.
+// This allows any AIAgent (not just ChatClientAgent) to benefit from MessageAIContextProvider-based
+// context enrichment. Multiple providers can be passed to Use and they are called in sequence,
+// each receiving the output of the previous one.
+Console.WriteLine("\n\n=== Example 5: MessageAIContextProvider middleware ===");
+
+var contextProviderAgent = originalAgent
+    .AsBuilder()
+    .Use([new DateTimeContextProvider()])
+    .Build();
+
+var contextResponse = await contextProviderAgent.RunAsync("Is it almost time for lunch?");
+Console.WriteLine($"Context-enriched response: {contextResponse}");
+
 // Function invocation middleware that logs before and after function calls.
 async ValueTask<object?> FunctionCallMiddleware(AIAgent agent, FunctionInvocationContext context, Func<FunctionInvocationContext, CancellationToken, ValueTask<object?>> next, CancellationToken cancellationToken)
 {
@@ -259,3 +274,23 @@ async Task<ChatResponse> PerRequestChatClientMiddleware(IEnumerable<ChatMessage>
 
     return response;
 }
+
+/// <summary>
+/// A <see cref="MessageAIContextProvider"/> that injects the current date and time into the agent's context.
+/// This is a simple example of how to use a MessageAIContextProvider to enrich agent messages
+/// via the <see cref="AIAgentBuilder.Use(MessageAIContextProvider[])"/> extension method.
+/// </summary>
+internal sealed class DateTimeContextProvider : MessageAIContextProvider
+{
+    protected override ValueTask<IEnumerable<ChatMessage>> ProvideMessagesAsync(
+        InvokingContext context,
+        CancellationToken cancellationToken = default)
+    {
+        Console.WriteLine("DateTimeContextProvider - Injecting current date/time context");
+
+        return new ValueTask<IEnumerable<ChatMessage>>(
+            [
+                new ChatMessage(ChatRole.User, $"For reference, the current date and time is: {DateTimeOffset.Now}")
+            ]);
+    }
+}

dotnet/samples/GettingStarted/Agents/Agent_Step14_Middleware/README.md

@@ -14,6 +14,7 @@ This sample demonstrates how to add middleware to intercept:
 5. Per‑request chat client middleware
 6. Per‑request function pipeline with approval
 7. Combining agent‑level and per‑request middleware
+8. MessageAIContextProvider middleware via `AIAgentBuilder.Use(...)` for injecting additional context messages
 
 ## Function Invocation Middleware
 

dotnet/samples/GettingStarted/Agents/Agent_Step20_AdditionalAIContext/Program.cs

@@ -146,11 +146,11 @@ namespace SampleApp
     }
 
     /// <summary>
-    /// An <see cref="AIContextProvider"/> which searches for upcoming calendar events and adds them to the AI context.
+    /// A <see cref="MessageAIContextProvider"/> which searches for upcoming calendar events and adds them to the AI context.
     /// </summary>
-    internal sealed class CalendarSearchAIContextProvider(Func<Task<string[]>> loadNextThreeCalendarEvents) : AIContextProvider
+    internal sealed class CalendarSearchAIContextProvider(Func<Task<string[]>> loadNextThreeCalendarEvents) : MessageAIContextProvider
     {
-        protected override async ValueTask<AIContext> ProvideAIContextAsync(InvokingContext context, CancellationToken cancellationToken = default)
+        protected override async ValueTask<IEnumerable<MEAI.ChatMessage>> ProvideMessagesAsync(InvokingContext context, CancellationToken cancellationToken = default)
         {
             var events = await loadNextThreeCalendarEvents();
 
@@ -161,10 +161,7 @@ namespace SampleApp
                 outputMessageBuilder.AppendLine($" - {calendarEvent}");
             }
 
-            return new AIContext
-            {
-                Messages = [new MEAI.ChatMessage(ChatRole.User, outputMessageBuilder.ToString())]
-            };
+            return [new MEAI.ChatMessage(ChatRole.User, outputMessageBuilder.ToString())];
         }
     }
 }