.NET: [BREAKING] Refactor ChatMessageStore methods to be similar to AIContextProvider and add filtering support

dotnet/samples/GettingStarted/AgentProviders/Agent_With_CustomImplementation/Program.cs

@@ -44,11 +44,19 @@ public override async Task<AgentRunResponse> RunAsync(IEnumerable<ChatMessage> m
                 throw new ArgumentException($"The provided thread is not of type {nameof(CustomAgentThread)}.", nameof(thread));
             }
 
+            // Get existing messages from the store
+            var invokingContext = new ChatMessageStore.InvokingContext(messages);
+            var storeMessages = await typedThread.MessageStore.InvokingAsync(invokingContext, cancellationToken);
+
             // Clone the input messages and turn them into response messages with upper case text.
             List<ChatMessage> responseMessages = CloneAndToUpperCase(messages, this.DisplayName).ToList();
 
             // Notify the thread of the input and output messages.
-            await typedThread.MessageStore.AddMessagesAsync(messages.Concat(responseMessages), cancellationToken);
+            var invokedContext = new ChatMessageStore.InvokedContext(messages, storeMessages)
+            {
+                ResponseMessages = responseMessages
+            };
+            await typedThread.MessageStore.InvokedAsync(invokedContext, cancellationToken);
 
             return new AgentRunResponse
             {
@@ -68,11 +76,19 @@ public override async IAsyncEnumerable<AgentRunResponseUpdate> RunStreamingAsync
                 throw new ArgumentException($"The provided thread is not of type {nameof(CustomAgentThread)}.", nameof(thread));
             }
 
+            // Get existing messages from the store
+            var invokingContext = new ChatMessageStore.InvokingContext(messages);
+            var storeMessages = await typedThread.MessageStore.InvokingAsync(invokingContext, cancellationToken);
+
             // Clone the input messages and turn them into response messages with upper case text.
             List<ChatMessage> responseMessages = CloneAndToUpperCase(messages, this.DisplayName).ToList();
 
             // Notify the thread of the input and output messages.
-            await typedThread.MessageStore.AddMessagesAsync(messages.Concat(responseMessages), cancellationToken);
+            var invokedContext = new ChatMessageStore.InvokedContext(messages, storeMessages)
+            {
+                ResponseMessages = responseMessages
+            };
+            await typedThread.MessageStore.InvokedAsync(invokedContext, cancellationToken);
 
             foreach (var message in responseMessages)
             {

dotnet/samples/GettingStarted/AgentWithRAG/AgentWithRAG_Step01_BasicTextRAG/Program.cs

@@ -62,7 +62,12 @@
     .CreateAIAgent(new ChatClientAgentOptions
     {
         ChatOptions = new() { Instructions = "You are a helpful support specialist for Contoso Outdoors. Answer questions using the provided context and cite the source document when available." },
-        AIContextProviderFactory = ctx => new TextSearchProvider(SearchAdapter, ctx.SerializedState, ctx.JsonSerializerOptions, textSearchOptions)
+        AIContextProviderFactory = ctx => new TextSearchProvider(SearchAdapter, ctx.SerializedState, ctx.JsonSerializerOptions, textSearchOptions),
+        // Since we are using ChatCompletion which stores chat history locally, we can also add a message removal policy
+        // that removes messages produced by the TextSearchProvider before they are added to the chat history, so that
+        // we don't bloat chat history with all the search result messages.
+        ChatMessageStoreFactory = ctx => new InMemoryChatMessageStore(ctx.SerializedState, ctx.JsonSerializerOptions)
+            .WithAIContextProviderMessageRemoval(),
     });
 
 AgentThread thread = agent.GetNewThread();

dotnet/samples/GettingStarted/Agents/Agent_Step07_3rdPartyThreadStorage/Program.cs

@@ -88,24 +88,7 @@ public VectorChatMessageStore(VectorStore vectorStore, JsonElement serializedSto
 
         public string? ThreadDbKey { get; private set; }
 
-        public override async Task AddMessagesAsync(IEnumerable<ChatMessage> messages, CancellationToken cancellationToken = default)
-        {
-            this.ThreadDbKey ??= Guid.NewGuid().ToString("N");
-
-            var collection = this._vectorStore.GetCollection<string, ChatHistoryItem>("ChatHistory");
-            await collection.EnsureCollectionExistsAsync(cancellationToken);
-
-            await collection.UpsertAsync(messages.Select(x => new ChatHistoryItem()
-            {
-                Key = this.ThreadDbKey + x.MessageId,
-                Timestamp = DateTimeOffset.UtcNow,
-                ThreadId = this.ThreadDbKey,
-                SerializedMessage = JsonSerializer.Serialize(x),
-                MessageText = x.Text
-            }), cancellationToken);
-        }
-
-        public override async Task<IEnumerable<ChatMessage>> GetMessagesAsync(CancellationToken cancellationToken = default)
+        public override async ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
         {
             var collection = this._vectorStore.GetCollection<string, ChatHistoryItem>("ChatHistory");
             await collection.EnsureCollectionExistsAsync(cancellationToken);
@@ -123,6 +106,33 @@ public override async Task<IEnumerable<ChatMessage>> GetMessagesAsync(Cancellati
             return messages;
         }
 
+        public override async ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+        {
+            // Don't store messages if the request failed.
+            if (context.InvokeException is not null)
+            {
+                return;
+            }
+
+            this.ThreadDbKey ??= Guid.NewGuid().ToString("N");
+
+            var collection = this._vectorStore.GetCollection<string, ChatHistoryItem>("ChatHistory");
+            await collection.EnsureCollectionExistsAsync(cancellationToken);
+
+            // Add both request and response messages to the store
+            // Optionally messages produced by the AIContextProvider can also be persisted (not shown).
+            var allNewMessages = context.RequestMessages.Concat(context.AIContextProviderMessages ?? []).Concat(context.ResponseMessages ?? []);
+
+            await collection.UpsertAsync(allNewMessages.Select(x => new ChatHistoryItem()
+            {
+                Key = this.ThreadDbKey + x.MessageId,
+                Timestamp = DateTimeOffset.UtcNow,
+                ThreadId = this.ThreadDbKey,
+                SerializedMessage = JsonSerializer.Serialize(x),
+                MessageText = x.Text
+            }), cancellationToken);
+        }
+
         public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null) =>
             // We have to serialize the thread id, so that on deserialization we can retrieve the messages using the same thread id.
             JsonSerializer.SerializeToElement(this.ThreadDbKey);

dotnet/src/Microsoft.Agents.AI.Abstractions/ChatMessageStore.cs

@@ -32,8 +32,9 @@ namespace Microsoft.Agents.AI;
 public abstract class ChatMessageStore
 {
     /// <summary>
-    /// Asynchronously retrieves all messages from the store that should be provided as context for the next agent invocation.
+    /// Called at the start of agent invocation to retrieve all messages from the store that should be provided as context for the next agent invocation.
     /// </summary>
+    /// <param name="context">Contains the request context including the caller provided messages that will be used by the agent for this invocation.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>
     /// A task that represents the asynchronous operation. The task result contains a collection of <see cref="ChatMessage"/>
@@ -59,20 +60,19 @@ public abstract class ChatMessageStore
     /// and context management.
     /// </para>
     /// </remarks>
-    public abstract Task<IEnumerable<ChatMessage>> GetMessagesAsync(CancellationToken cancellationToken = default);
+    public abstract ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default);
 
     /// <summary>
-    /// Asynchronously adds new messages to the store.
+    /// Called at the end of the agent invocation to add new messages to the store.
     /// </summary>
-    /// <param name="messages">The collection of chat messages to add to the store.</param>
+    /// <param name="context">Contains the invocation context including request messages, response messages, and any exception that occurred.</param>
     /// <param name="cancellationToken">The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.</param>
     /// <returns>A task that represents the asynchronous add operation.</returns>
-    /// <exception cref="ArgumentNullException"><paramref name="messages"/> is <see langword="null"/>.</exception>
     /// <remarks>
     /// <para>
     /// Messages should be added in the order they were generated to maintain proper chronological sequence.
     /// The store is responsible for preserving message ordering and ensuring that subsequent calls to
-    /// <see cref="GetMessagesAsync"/> return messages in the correct chronological order.
+    /// <see cref="InvokingAsync"/> return messages in the correct chronological order.
     /// </para>
     /// <para>
     /// Implementations may perform additional processing during message addition, such as:
@@ -83,8 +83,12 @@ public abstract class ChatMessageStore
     /// <item><description>Updating indices or search capabilities</description></item>
     /// </list>
     /// </para>
+    /// <para>
+    /// This method is called regardless of whether the invocation succeeded or failed.
+    /// To check if the invocation was successful, inspect the <see cref="InvokedContext.InvokeException"/> property.
+    /// </para>
     /// </remarks>
-    public abstract Task AddMessagesAsync(IEnumerable<ChatMessage> messages, CancellationToken cancellationToken = default);
+    public abstract ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default);
 
     /// <summary>
     /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
@@ -121,4 +125,100 @@ public abstract class ChatMessageStore
     /// </remarks>
     public TService? GetService<TService>(object? serviceKey = null)
         => this.GetService(typeof(TService), serviceKey) is TService service ? service : default;
+
+    /// <summary>
+    /// Contains the context information provided to <see cref="InvokingAsync(InvokingContext, CancellationToken)"/>.
+    /// </summary>
+    /// <remarks>
+    /// This class provides context about the invocation before the messages are retrieved from the store,
+    /// including the new messages that will be used. Stores can use this information to determine what
+    /// messages should be retrieved for the invocation.
+    /// </remarks>
+    public sealed class InvokingContext
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="InvokingContext"/> class with the specified request messages.
+        /// </summary>
+        /// <param name="requestMessages">The new messages to be used by the agent for this invocation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="requestMessages"/> is <see langword="null"/>.</exception>
+        public InvokingContext(IEnumerable<ChatMessage> requestMessages)
+        {
+            this.RequestMessages = requestMessages ?? throw new ArgumentNullException(nameof(requestMessages));
+        }
+
+        /// <summary>
+        /// Gets the caller provided messages that will be used by the agent for this invocation.
+        /// </summary>
+        /// <value>
+        /// A collection of <see cref="ChatMessage"/> instances representing new messages that were provided by the caller.
+        /// </value>
+        public IEnumerable<ChatMessage> RequestMessages { get; }
+    }
+
+    /// <summary>
+    /// Contains the context information provided to <see cref="InvokedAsync(InvokedContext, CancellationToken)"/>.
+    /// </summary>
+    /// <remarks>
+    /// This class provides context about a completed agent invocation, including both the
+    /// request messages that were used and the response messages that were generated. It also indicates
+    /// whether the invocation succeeded or failed.
+    /// </remarks>
+    public sealed class InvokedContext
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="InvokedContext"/> class with the specified request messages.
+        /// </summary>
+        /// <param name="requestMessages">The caller provided messages that were used by the agent for this invocation.</param>
+        /// <param name="chatMessageStoreMessages">The messages retrieved from the <see cref="ChatMessageStore"/> for this invocation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="requestMessages"/> is <see langword="null"/>.</exception>
+        public InvokedContext(IEnumerable<ChatMessage> requestMessages, IEnumerable<ChatMessage> chatMessageStoreMessages)
+        {
+            this.RequestMessages = Throw.IfNull(requestMessages);
+            this.ChatMessageStoreMessages = chatMessageStoreMessages;
+        }
+
+        /// <summary>
+        /// Gets the caller provided messages that were used by the agent for this invocation.
+        /// </summary>
+        /// <value>
+        /// A collection of <see cref="ChatMessage"/> instances representing new messages that were provided by the caller.
+        /// This does not include any <see cref="ChatMessageStore"/> supplied messages.
+        /// </value>
+        public IEnumerable<ChatMessage> RequestMessages { get; }
+
+        /// <summary>
+        /// Gets the messages retrieved from the <see cref="ChatMessageStore"/> for this invocation, if any.
+        /// </summary>
+        /// <value>
+        /// A collection of <see cref="ChatMessage"/> instances that were retrieved from the <see cref="ChatMessageStore"/>,
+        /// and were used by the agent as part of the invocation.
+        /// </value>
+        public IEnumerable<ChatMessage> ChatMessageStoreMessages { get; }
+
+        /// <summary>
+        /// Gets or sets the messages provided by the <see cref="AIContextProvider"/> for this invocation, if any.
+        /// </summary>
+        /// <value>
+        /// A collection of <see cref="ChatMessage"/> instances that were provided by the <see cref="AIContextProvider"/>,
+        /// and were used by the agent as part of the invocation.
+        /// </value>
+        public IEnumerable<ChatMessage>? AIContextProviderMessages { get; set; }
+
+        /// <summary>
+        /// Gets the collection of response messages generated during this invocation if the invocation succeeded.
+        /// </summary>
+        /// <value>
+        /// A collection of <see cref="ChatMessage"/> instances representing the response,
+        /// or <see langword="null"/> if the invocation failed or did not produce response messages.
+        /// </value>
+        public IEnumerable<ChatMessage>? ResponseMessages { get; set; }
+
+        /// <summary>
+        /// Gets the <see cref="Exception"/> that was thrown during the invocation, if the invocation failed.
+        /// </summary>
+        /// <value>
+        /// The exception that caused the invocation to fail, or <see langword="null"/> if the invocation succeeded.
+        /// </value>
+        public Exception? InvokeException { get; set; }
+    }
 }

dotnet/src/Microsoft.Agents.AI.Abstractions/ChatMessageStoreExtensions.cs

@@ -0,0 +1,50 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Contains extension methods for the <see cref="ChatMessageStore"/> class.
+/// </summary>
+public static class ChatMessageStoreExtensions
+{
+    /// <summary>
+    /// Adds message filtering to an existing store, so that messages passed to the store and messages produced by the store
+    /// can be filtered, updated or replaced.
+    /// </summary>
+    /// <param name="store">The store to add the message filter to.</param>
+    /// <param name="invokingMessagesFilter">An optional filter function to apply to messages before they are invoked. If null, no filter is applied at this
+    /// stage.</param>
+    /// <param name="invokedMessagesFilter">An optional filter function to apply to the invocation context after messages have been invoked. If null, no
+    /// filter is applied at this stage.</param>
+    /// <returns>The <see cref="ChatMessageStore"/> with filtering applied.</returns>
+    public static ChatMessageStore WithMessageFilters(
+        this ChatMessageStore store,
+        Func<IEnumerable<ChatMessage>, IEnumerable<ChatMessage>>? invokingMessagesFilter = null,
+        Func<ChatMessageStore.InvokedContext, ChatMessageStore.InvokedContext>? invokedMessagesFilter = null)
+    {
+        return new ChatMessageStoreMessageFilter(
+            innerChatMessageStore: store,
+            invokingMessagesFilter: invokingMessagesFilter,
+            invokedMessagesFilter: invokedMessagesFilter);
+    }
+
+    /// <summary>
+    /// Decorates the provided chat message store so that it does not store messages produced by any <see cref="AIContextProvider"/>.
+    /// </summary>
+    /// <param name="store">The store to add the message filter to.</param>
+    /// <returns>A new <see cref="ChatMessageStore"/> instance that filters out <see cref="AIContextProvider"/> messages so they do not get stored.</returns>
+    public static ChatMessageStore WithAIContextProviderMessageRemoval(this ChatMessageStore store)
+    {
+        return new ChatMessageStoreMessageFilter(
+            innerChatMessageStore: store,
+            invokedMessagesFilter: (ctx) =>
+            {
+                ctx.AIContextProviderMessages = null;
+                return ctx;
+            });
+    }
+}