.NET: [BREAKING] Add ability to mark the source of Agent request messages and use that for filtering (#3540)

* Add ability to mark the source of Agent request messages and use that for filtering

* Add support for source, in addition to source type, and add unit tests for automatic stamping

* Address PR comments.

* Add merge fixes

* Address PR comments

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

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -31,6 +32,25 @@ namespace Microsoft.Agents.AI;
 /// </remarks>
 public abstract class AIContextProvider
 {
+    private readonly string _sourceName;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AIContextProvider"/> class.
+    /// </summary>
+    protected AIContextProvider()
+    {
+        this._sourceName = this.GetType().FullName!;
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AIContextProvider"/> class with the specified source name.
+    /// </summary>
+    /// <param name="sourceName">The source name to stamp on <see cref="ChatMessage.AdditionalProperties"/> for each messages produced by the <see cref="AIContextProvider"/>.</param>
+    protected AIContextProvider(string sourceName)
+    {
+        this._sourceName = sourceName;
+    }
+
     /// <summary>
     /// Called at the start of agent invocation to provide additional context.
     /// </summary>
@@ -48,7 +68,57 @@ public abstract class AIContextProvider
     /// </list>
     /// </para>
     /// </remarks>
-    public abstract ValueTask<AIContext> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default);
+    public async ValueTask<AIContext> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    {
+        var aiContext = await this.InvokingCoreAsync(context, cancellationToken).ConfigureAwait(false);
+        if (aiContext.Messages is null)
+        {
+            return aiContext;
+        }
+
+        aiContext.Messages = aiContext.Messages.Select(message =>
+        {
+            if (message.AdditionalProperties != null
+                // Check if the message was already tagged with this provider's source type
+                && message.AdditionalProperties.TryGetValue(AgentRequestMessageSourceType.AdditionalPropertiesKey, out var messageSourceType)
+                && messageSourceType is AgentRequestMessageSourceType typedMessageSourceType
+                && typedMessageSourceType == AgentRequestMessageSourceType.AIContextProvider
+                // Check if the message was already tagged with this provider's source
+                && message.AdditionalProperties.TryGetValue(AgentRequestMessageSource.AdditionalPropertiesKey, out var messageSource)
+                && messageSource is string typedMessageSource
+                && typedMessageSource == this._sourceName)
+            {
+                return message;
+            }
+
+            message = message.Clone();
+            message.AdditionalProperties ??= new();
+            message.AdditionalProperties[AgentRequestMessageSourceType.AdditionalPropertiesKey] = AgentRequestMessageSourceType.AIContextProvider;
+            message.AdditionalProperties[AgentRequestMessageSource.AdditionalPropertiesKey] = this._sourceName;
+            return message;
+        }).ToList();
+
+        return aiContext;
+    }
+
+    /// <summary>
+    /// Called at the start of agent invocation to provide additional context.
+    /// </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 the <see cref="AIContext"/> with additional context to be used by the agent during this invocation.</returns>
+    /// <remarks>
+    /// <para>
+    /// Implementers can load any additional context required at this time, such as:
+    /// <list type="bullet">
+    /// <item><description>Retrieving relevant information from knowledge bases</description></item>
+    /// <item><description>Adding system instructions or prompts</description></item>
+    /// <item><description>Providing function tools for the current invocation</description></item>
+    /// <item><description>Injecting contextual messages from conversation history</description></item>
+    /// </list>
+    /// </para>
+    /// </remarks>
+    protected abstract ValueTask<AIContext> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default);
 
     /// <summary>
     /// Called at the end of the agent invocation to process the invocation results.
@@ -71,7 +141,31 @@ public abstract class AIContextProvider
     /// To check if the invocation was successful, inspect the <see cref="InvokedContext.InvokeException"/> property.
     /// </para>
     /// </remarks>
-    public virtual ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    public ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+        => this.InvokedCoreAsync(context, cancellationToken);
+
+    /// <summary>
+    /// Called at the end of the agent invocation to process the invocation results.
+    /// </summary>
+    /// <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 operation.</returns>
+    /// <remarks>
+    /// <para>
+    /// Implementers can use the request and response messages in the provided <paramref name="context"/> to:
+    /// <list type="bullet">
+    /// <item><description>Update internal state based on conversation outcomes</description></item>
+    /// <item><description>Extract and store memories or preferences from user messages</description></item>
+    /// <item><description>Log or audit conversation details</description></item>
+    /// <item><description>Perform cleanup or finalization tasks</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>
+    protected virtual ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
         => default;
 
     /// <summary>
@@ -117,7 +211,7 @@ public abstract class AIContextProvider
         => this.GetService(typeof(TService), serviceKey) is TService service ? service : default;
 
     /// <summary>
-    /// Contains the context information provided to <see cref="InvokingAsync(InvokingContext, CancellationToken)"/>.
+    /// Contains the context information provided to <see cref="InvokingCoreAsync(InvokingContext, CancellationToken)"/>.
     /// </summary>
     /// <remarks>
     /// This class provides context about the invocation before the underlying AI model is invoked, including the messages
@@ -163,7 +257,7 @@ public abstract class AIContextProvider
     }
 
     /// <summary>
-    /// Contains the context information provided to <see cref="InvokedAsync(InvokedContext, CancellationToken)"/>.
+    /// Contains the context information provided to <see cref="InvokedCoreAsync(InvokedContext, CancellationToken)"/>.
     /// </summary>
     /// <remarks>
     /// This class provides context about a completed agent invocation, including both the
@@ -178,18 +272,15 @@ public abstract class AIContextProvider
         /// <param name="agent">The agent being invoked.</param>
         /// <param name="session">The session associated with the agent invocation.</param>
         /// <param name="requestMessages">The caller provided messages that were used by the agent for this invocation.</param>
-        /// <param name="aiContextProviderMessages">The messages provided by the <see cref="AIContextProvider"/> for this invocation, if any.</param>
         /// <exception cref="ArgumentNullException"><paramref name="requestMessages"/> is <see langword="null"/>.</exception>
         public InvokedContext(
             AIAgent agent,
             AgentSession? session,
-            IEnumerable<ChatMessage> requestMessages,
-            IEnumerable<ChatMessage>? aiContextProviderMessages)
+            IEnumerable<ChatMessage> requestMessages)
         {
             this.Agent = Throw.IfNull(agent);
             this.Session = session;
             this.RequestMessages = Throw.IfNull(requestMessages);
-            this.AIContextProviderMessages = aiContextProviderMessages;
         }
 
         /// <summary>
@@ -211,15 +302,6 @@ public abstract class AIContextProvider
         /// </value>
         public IEnumerable<ChatMessage> RequestMessages { get; set { field = Throw.IfNull(value); } }
 
-        /// <summary>
-        /// Gets 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>

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

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Provides a constant for the key used to store the source of the agent request message.
+/// </summary>
+public static class AgentRequestMessageSource
+{
+    /// <summary>
+    /// Provides the key used in <see cref="ChatMessage.AdditionalProperties"/> to store the source of the agent request message.
+    /// </summary>
+    public static readonly string AdditionalPropertiesKey = "Agent.RequestMessageSource";
+}

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

@@ -0,0 +1,106 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using Microsoft.Extensions.AI;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Represents the source of an agent request message.
+/// </summary>
+/// <remarks>
+/// Input messages for a specific agent run can originate from various sources.
+/// This type helps to identify whether a message came from outside the agent pipeline,
+/// whether it was produced by middleware, or came from chat history.
+/// </remarks>
+public sealed class AgentRequestMessageSourceType : IEquatable<AgentRequestMessageSourceType>
+{
+    /// <summary>
+    /// Provides the key used in <see cref="ChatMessage.AdditionalProperties"/> to store the source type of the agent request message.
+    /// </summary>
+    public static readonly string AdditionalPropertiesKey = "Agent.RequestMessageSourceType";
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AgentRequestMessageSourceType"/> class.
+    /// </summary>
+    /// <param name="value">The string value representing the source of the agent request message.</param>
+    public AgentRequestMessageSourceType(string value) => this.Value = Throw.IfNullOrWhitespace(value);
+
+    /// <summary>
+    /// Get the string value representing the source of the agent request message.
+    /// </summary>
+    public string Value { get; }
+
+    /// <summary>
+    /// The message came from outside the agent pipeline (e.g., user input).
+    /// </summary>
+    public static AgentRequestMessageSourceType External { get; } = new AgentRequestMessageSourceType(nameof(External));
+
+    /// <summary>
+    /// The message was produced by middleware.
+    /// </summary>
+    public static AgentRequestMessageSourceType AIContextProvider { get; } = new AgentRequestMessageSourceType(nameof(AIContextProvider));
+
+    /// <summary>
+    /// The message came from chat history.
+    /// </summary>
+    public static AgentRequestMessageSourceType ChatHistory { get; } = new AgentRequestMessageSourceType(nameof(ChatHistory));
+
+    /// <summary>
+    /// Determines whether this instance and another specified <see cref="AgentRequestMessageSourceType"/> object have the same value.
+    /// </summary>
+    /// <param name="other">The <see cref="AgentRequestMessageSourceType"/> to compare to this instance.</param>
+    /// <returns><see langword="true"/> if the value of the <paramref name="other"/> parameter is the same as the value of this instance; otherwise, <see langword="false"/>.</returns>
+    public bool Equals(AgentRequestMessageSourceType? other)
+    {
+        if (other is null)
+        {
+            return false;
+        }
+
+        if (ReferenceEquals(this, other))
+        {
+            return true;
+        }
+
+        return string.Equals(this.Value, other.Value, StringComparison.Ordinal);
+    }
+
+    /// <summary>
+    /// Determines whether this instance and a specified object have the same value.
+    /// </summary>
+    /// <param name="obj">The object to compare to this instance.</param>
+    /// <returns><see langword="true"/> if <paramref name="obj"/> is a <see cref="AgentRequestMessageSourceType"/> and its value is the same as this instance; otherwise, <see langword="false"/>.</returns>
+    public override bool Equals(object? obj) => this.Equals(obj as AgentRequestMessageSourceType);
+
+    /// <summary>
+    /// Returns the hash code for this instance.
+    /// </summary>
+    /// <returns>A 32-bit signed integer hash code.</returns>
+    public override int GetHashCode() => this.Value?.GetHashCode() ?? 0;
+
+    /// <summary>
+    /// Determines whether two specified <see cref="AgentRequestMessageSourceType"/> objects have the same value.
+    /// </summary>
+    /// <param name="left">The first <see cref="AgentRequestMessageSourceType"/> to compare.</param>
+    /// <param name="right">The second <see cref="AgentRequestMessageSourceType"/> to compare.</param>
+    /// <returns><see langword="true"/> if the value of <paramref name="left"/> is the same as the value of <paramref name="right"/>; otherwise, <see langword="false"/>.</returns>
+    public static bool operator ==(AgentRequestMessageSourceType? left, AgentRequestMessageSourceType? right)
+    {
+        if (left is null)
+        {
+            return right is null;
+        }
+
+        return left.Equals(right);
+    }
+
+    /// <summary>
+    /// Determines whether two specified <see cref="AgentRequestMessageSourceType"/> objects have different values.
+    /// </summary>
+    /// <param name="left">The first <see cref="AgentRequestMessageSourceType"/> to compare.</param>
+    /// <param name="right">The second <see cref="AgentRequestMessageSourceType"/> to compare.</param>
+    /// <returns><see langword="true"/> if the value of <paramref name="left"/> is different from the value of <paramref name="right"/>; otherwise, <see langword="false"/>.</returns>
+    public static bool operator !=(AgentRequestMessageSourceType? left, AgentRequestMessageSourceType? right) => !(left == right);
+}

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

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
@@ -36,6 +37,25 @@ namespace Microsoft.Agents.AI;
 /// </remarks>
 public abstract class ChatHistoryProvider
 {
+    private readonly string _sourceName;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ChatHistoryProvider"/> class.
+    /// </summary>
+    protected ChatHistoryProvider()
+    {
+        this._sourceName = this.GetType().FullName!;
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ChatHistoryProvider"/> class with the specified source name.
+    /// </summary>
+    /// <param name="sourceName">The source name to stamp on <see cref="ChatMessage.AdditionalProperties"/> for each messages produced by the <see cref="ChatHistoryProvider"/>.</param>
+    protected ChatHistoryProvider(string sourceName)
+    {
+        this._sourceName = sourceName;
+    }
+
     /// <summary>
     /// Called at the start of agent invocation to provide messages from the chat history as context for the next agent invocation.
     /// </summary>
@@ -65,7 +85,63 @@ public abstract class ChatHistoryProvider
     /// and context management.
     /// </para>
     /// </remarks>
-    public abstract ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default);
+    public async ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    {
+        var messages = await this.InvokingCoreAsync(context, cancellationToken).ConfigureAwait(false);
+
+        return messages.Select(message =>
+        {
+            if (message.AdditionalProperties != null
+                // Check if the message was already tagged with this provider's source type
+                && message.AdditionalProperties.TryGetValue(AgentRequestMessageSourceType.AdditionalPropertiesKey, out var messageSourceType)
+                && messageSourceType is AgentRequestMessageSourceType typedMessageSourceType
+                && typedMessageSourceType == AgentRequestMessageSourceType.ChatHistory
+                // Check if the message was already tagged with this provider's source
+                && message.AdditionalProperties.TryGetValue(AgentRequestMessageSource.AdditionalPropertiesKey, out var messageSource)
+                && messageSource is string typedMessageSource
+                && typedMessageSource == this._sourceName)
+            {
+                return message;
+            }
+
+            message = message.Clone();
+            message.AdditionalProperties ??= new();
+            message.AdditionalProperties[AgentRequestMessageSourceType.AdditionalPropertiesKey] = AgentRequestMessageSourceType.ChatHistory;
+            message.AdditionalProperties[AgentRequestMessageSource.AdditionalPropertiesKey] = this._sourceName;
+            return message;
+        });
+    }
+
+    /// <summary>
+    /// Called at the start of agent invocation to provide messages from the chat history 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"/>
+    /// instances in ascending chronological order (oldest first).
+    /// </returns>
+    /// <remarks>
+    /// <para>
+    /// Messages are returned in chronological order to maintain proper conversation flow and context for the agent.
+    /// The oldest messages appear first in the collection, followed by more recent messages.
+    /// </para>
+    /// <para>
+    /// If the total message history becomes very large, implementations should apply appropriate strategies to manage
+    /// storage constraints, such as:
+    /// <list type="bullet">
+    /// <item><description>Truncating older messages while preserving recent context</description></item>
+    /// <item><description>Summarizing message groups to maintain essential context</description></item>
+    /// <item><description>Implementing sliding window approaches for message retention</description></item>
+    /// <item><description>Archiving old messages while keeping active conversation context</description></item>
+    /// </list>
+    /// </para>
+    /// <para>
+    /// Each <see cref="ChatHistoryProvider"/> instance should be associated with a single <see cref="AgentSession"/> to ensure proper message isolation
+    /// and context management.
+    /// </para>
+    /// </remarks>
+    protected abstract ValueTask<IEnumerable<ChatMessage>> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default);
 
     /// <summary>
     /// Called at the end of the agent invocation to add new messages to the chat history.
@@ -77,7 +153,7 @@ public abstract class ChatHistoryProvider
     /// <para>
     /// Messages should be added in the order they were generated to maintain proper chronological sequence.
     /// The <see cref="ChatHistoryProvider"/> is responsible for preserving message ordering and ensuring that subsequent calls to
-    /// <see cref="InvokingAsync"/> return messages in the correct chronological order.
+    /// <see cref="InvokingCoreAsync"/> return messages in the correct chronological order.
     /// </para>
     /// <para>
     /// Implementations may perform additional processing during message addition, such as:
@@ -92,7 +168,35 @@ public abstract class ChatHistoryProvider
     /// To check if the invocation was successful, inspect the <see cref="InvokedContext.InvokeException"/> property.
     /// </para>
     /// </remarks>
-    public abstract ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default);
+    public ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default) =>
+        this.InvokedCoreAsync(context, cancellationToken);
+
+    /// <summary>
+    /// Called at the end of the agent invocation to add new messages to the chat history.
+    /// </summary>
+    /// <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>
+    /// <remarks>
+    /// <para>
+    /// Messages should be added in the order they were generated to maintain proper chronological sequence.
+    /// The <see cref="ChatHistoryProvider"/> is responsible for preserving message ordering and ensuring that subsequent calls to
+    /// <see cref="InvokingCoreAsync"/> return messages in the correct chronological order.
+    /// </para>
+    /// <para>
+    /// Implementations may perform additional processing during message addition, such as:
+    /// <list type="bullet">
+    /// <item><description>Validating message content and metadata</description></item>
+    /// <item><description>Applying storage optimizations or compression</description></item>
+    /// <item><description>Triggering background maintenance operations</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>
+    protected abstract ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default);
 
     /// <summary>
     /// Serializes the current object's state to a <see cref="JsonElement"/> using the specified serialization options.
@@ -131,7 +235,7 @@ public abstract class ChatHistoryProvider
         => this.GetService(typeof(TService), serviceKey) is TService service ? service : default;
 
     /// <summary>
-    /// Contains the context information provided to <see cref="InvokingAsync(InvokingContext, CancellationToken)"/>.
+    /// Contains the context information provided to <see cref="InvokingCoreAsync(InvokingContext, CancellationToken)"/>.
     /// </summary>
     /// <remarks>
     /// This class provides context about the invocation including the new messages that will be used.
@@ -177,7 +281,7 @@ public abstract class ChatHistoryProvider
     }
 
     /// <summary>
-    /// Contains the context information provided to <see cref="InvokedAsync(InvokedContext, CancellationToken)"/>.
+    /// Contains the context information provided to <see cref="InvokedCoreAsync(InvokedContext, CancellationToken)"/>.
     /// </summary>
     /// <remarks>
     /// This class provides context about a completed agent invocation, including both the
@@ -192,18 +296,15 @@ public abstract class ChatHistoryProvider
         /// <param name="agent">The agent being invoked.</param>
         /// <param name="session">The session associated with the agent invocation.</param>
         /// <param name="requestMessages">The caller provided messages that were used by the agent for this invocation.</param>
-        /// <param name="chatHistoryProviderMessages">The messages retrieved from the <see cref="ChatHistoryProvider"/> for this invocation.</param>
         /// <exception cref="ArgumentNullException"><paramref name="requestMessages"/> is <see langword="null"/>.</exception>
         public InvokedContext(
             AIAgent agent,
             AgentSession? session,
-            IEnumerable<ChatMessage> requestMessages,
-            IEnumerable<ChatMessage>? chatHistoryProviderMessages)
+            IEnumerable<ChatMessage> requestMessages)
         {
             this.Agent = Throw.IfNull(agent);
             this.Session = session;
             this.RequestMessages = Throw.IfNull(requestMessages);
-            this.ChatHistoryProviderMessages = chatHistoryProviderMessages;
         }
 
         /// <summary>
@@ -225,24 +326,6 @@ public abstract class ChatHistoryProvider
         /// </value>
         public IEnumerable<ChatMessage> RequestMessages { get; set { field = Throw.IfNull(value); } }
 
-        /// <summary>
-        /// Gets the messages retrieved from the <see cref="ChatHistoryProvider"/> for this invocation, if any.
-        /// </summary>
-        /// <value>
-        /// A collection of <see cref="ChatMessage"/> instances that were retrieved from the <see cref="ChatHistoryProvider"/>,
-        /// and were used by the agent as part of the invocation.
-        /// </value>
-        public IEnumerable<ChatMessage>? ChatHistoryProviderMessages { get; set; }
-
-        /// <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>

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

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Microsoft.Extensions.AI;
 
 namespace Microsoft.Agents.AI;
@@ -33,8 +34,8 @@ public static class ChatHistoryProviderExtensions
     }
 
     /// <summary>
-    /// Decorates the provided chat message <see cref="ChatHistoryProvider"/> so that it does not add
-    /// messages produced by any <see cref="AIContextProvider"/> to chat history.
+    /// Decorates the provided <see cref="ChatHistoryProvider"/> so that it does not add
+    /// messages with <see cref="AgentRequestMessageSourceType.AIContextProvider"/> to chat history.
     /// </summary>
     /// <param name="provider">The <see cref="ChatHistoryProvider"/> to add the message filter to.</param>
     /// <returns>A new <see cref="ChatHistoryProvider"/> instance that filters out <see cref="AIContextProvider"/> messages so they do not get added.</returns>
@@ -44,7 +45,7 @@ public static class ChatHistoryProviderExtensions
             innerProvider: provider,
             invokedMessagesFilter: (ctx) =>
             {
-                ctx.AIContextProviderMessages = null;
+                ctx.RequestMessages = ctx.RequestMessages.Where(x => x.GetAgentRequestMessageSource() != AgentRequestMessageSourceType.AIContextProvider);
                 return ctx;
             });
     }

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

@@ -49,14 +49,14 @@ public sealed class ChatHistoryProviderMessageFilter : ChatHistoryProvider
     }
 
     /// <inheritdoc />
-    public override async ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask<IEnumerable<ChatMessage>> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default)
     {
         var messages = await this._innerProvider.InvokingAsync(context, cancellationToken).ConfigureAwait(false);
         return this._invokingMessagesFilter != null ? this._invokingMessagesFilter(messages) : messages;
     }
 
     /// <inheritdoc />
-    public override ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    protected override ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
     {
         if (this._invokedMessagesFilter != null)
         {

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

@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Contains extension methods for <see cref="ChatMessage"/>
+/// </summary>
+public static class ChatMessageExtensions
+{
+    /// <summary>
+    /// Gets the source of the provided <see cref="ChatMessage"/> in the context of messages passed into an agent run.
+    /// </summary>
+    /// <param name="message">The <see cref="ChatMessage"/> for which we need the source.</param>
+    /// <returns>An <see cref="AgentRequestMessageSourceType"/> value indicating the source of the <see cref="ChatMessage"/>. Defaults to <see
+    /// cref="AgentRequestMessageSourceType.External"/> if no explicit source is defined.</returns>
+    public static AgentRequestMessageSourceType GetAgentRequestMessageSource(this ChatMessage message)
+    {
+        if (message.AdditionalProperties?.TryGetValue(AgentRequestMessageSourceType.AdditionalPropertiesKey, out var source) is true && source is AgentRequestMessageSourceType typedSource)
+        {
+            return typedSource;
+        }
+
+        return AgentRequestMessageSourceType.External;
+    }
+}

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

@@ -133,7 +133,7 @@ public sealed class InMemoryChatHistoryProvider : ChatHistoryProvider, IList<Cha
     }
 
     /// <inheritdoc />
-    public override async ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask<IEnumerable<ChatMessage>> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default)
     {
         _ = Throw.IfNull(context);
 
@@ -146,7 +146,7 @@ public sealed class InMemoryChatHistoryProvider : ChatHistoryProvider, IList<Cha
     }
 
     /// <inheritdoc />
-    public override async ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
     {
         _ = Throw.IfNull(context);
 
@@ -155,8 +155,8 @@ public sealed class InMemoryChatHistoryProvider : ChatHistoryProvider, IList<Cha
             return;
         }
 
-        // Add request, AI context provider, and response messages to the provider
-        var allNewMessages = context.RequestMessages.Concat(context.AIContextProviderMessages ?? []).Concat(context.ResponseMessages ?? []);
+        // Add request and response messages to the provider
+        var allNewMessages = context.RequestMessages.Concat(context.ResponseMessages ?? []);
         this._messages.AddRange(allNewMessages);
 
         if (this.ReducerTriggerEvent is ChatReducerTriggerEvent.AfterMessageAdded && this.ChatReducer is not null)
@@ -229,7 +229,7 @@ public sealed class InMemoryChatHistoryProvider : ChatHistoryProvider, IList<Cha
     {
         /// <summary>
         /// Trigger the reducer when a new message is added.
-        /// <see cref="InvokedAsync(InvokedContext, CancellationToken)"/> will only complete when reducer processing is done.
+        /// <see cref="InvokedCoreAsync(InvokedContext, CancellationToken)"/> will only complete when reducer processing is done.
         /// </summary>
         AfterMessageAdded,
 

dotnet/src/Microsoft.Agents.AI.CosmosNoSql/CosmosChatHistoryProvider.cs

@@ -287,7 +287,7 @@ public sealed class CosmosChatHistoryProvider : ChatHistoryProvider, IDisposable
     }
 
     /// <inheritdoc />
-    public override async ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask<IEnumerable<ChatMessage>> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default)
     {
 #pragma warning disable CA1513 // Use ObjectDisposedException.ThrowIf - not available on all target frameworks
         if (this._disposed)
@@ -347,7 +347,7 @@ public sealed class CosmosChatHistoryProvider : ChatHistoryProvider, IDisposable
     }
 
     /// <inheritdoc />
-    public override async ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
     {
         Throw.IfNull(context);
 
@@ -364,7 +364,7 @@ public sealed class CosmosChatHistoryProvider : ChatHistoryProvider, IDisposable
         }
 #pragma warning restore CA1513
 
-        var messageList = context.RequestMessages.Concat(context.AIContextProviderMessages ?? []).Concat(context.ResponseMessages ?? []).ToList();
+        var messageList = context.RequestMessages.Concat(context.ResponseMessages ?? []).ToList();
         if (messageList.Count == 0)
         {
             return;

dotnet/src/Microsoft.Agents.AI.Mem0/Mem0Provider.cs

@@ -131,13 +131,16 @@ public sealed class Mem0Provider : AIContextProvider
     }
 
     /// <inheritdoc />
-    public override async ValueTask<AIContext> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask<AIContext> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default)
     {
         Throw.IfNull(context);
 
         string queryText = string.Join(
             Environment.NewLine,
-            context.RequestMessages.Where(m => !string.IsNullOrWhiteSpace(m.Text)).Select(m => m.Text));
+            context.RequestMessages
+                .Where(m => m.GetAgentRequestMessageSource() == AgentRequestMessageSourceType.External)
+                .Where(m => !string.IsNullOrWhiteSpace(m.Text))
+                .Select(m => m.Text));
 
         try
         {
@@ -202,7 +205,7 @@ public sealed class Mem0Provider : AIContextProvider
     }
 
     /// <inheritdoc />
-    public override async ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
     {
         if (context.InvokeException is not null)
         {
@@ -212,7 +215,11 @@ public sealed class Mem0Provider : AIContextProvider
         try
         {
             // Persist request and response messages after invocation.
-            await this.PersistMessagesAsync(context.RequestMessages.Concat(context.ResponseMessages ?? []), cancellationToken).ConfigureAwait(false);
+            await this.PersistMessagesAsync(
+                context.RequestMessages
+                    .Where(m => m.GetAgentRequestMessageSource() == AgentRequestMessageSourceType.External)
+                    .Concat(context.ResponseMessages ?? []),
+                cancellationToken).ConfigureAwait(false);
         }
         catch (Exception ex)
         {

dotnet/src/Microsoft.Agents.AI.Workflows/WorkflowChatHistoryProvider.cs

@@ -46,17 +46,17 @@ internal sealed class WorkflowChatHistoryProvider : ChatHistoryProvider
 
     internal void AddMessages(params IEnumerable<ChatMessage> messages) => this._chatMessages.AddRange(messages);
 
-    public override ValueTask<IEnumerable<ChatMessage>> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    protected override ValueTask<IEnumerable<ChatMessage>> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default)
         => new(this._chatMessages.AsReadOnly());
 
-    public override ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    protected override ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
     {
         if (context.InvokeException is not null)
         {
             return default;
         }
 
-        var allNewMessages = context.RequestMessages.Concat(context.AIContextProviderMessages ?? []).Concat(context.ResponseMessages ?? []);
+        var allNewMessages = context.RequestMessages.Concat(context.ResponseMessages ?? []);
         this._chatMessages.AddRange(allNewMessages);
 
         return default;

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

@@ -206,9 +206,8 @@ public sealed partial class ChatClientAgent : AIAgent
 
         (ChatClientAgentSession safeSession,
          ChatOptions? chatOptions,
+         List<ChatMessage> inputMessagesForProviders,
          List<ChatMessage> inputMessagesForChatClient,
-         IList<ChatMessage>? aiContextProviderMessages,
-         IList<ChatMessage>? chatHistoryProviderMessages,
          ChatClientAgentContinuationToken? continuationToken) =
             await this.PrepareSessionAndMessagesAsync(session, inputMessages, options, cancellationToken).ConfigureAwait(false);
 
@@ -227,12 +226,12 @@ public sealed partial class ChatClientAgent : AIAgent
         try
         {
             // Using the enumerator to ensure we consider the case where no updates are returned for notification.
-            responseUpdatesEnumerator = chatClient.GetStreamingResponseAsync(inputMessagesForChatClient, chatOptions, cancellationToken).GetAsyncEnumerator(cancellationToken);
+            responseUpdatesEnumerator = chatClient.GetStreamingResponseAsync(inputMessagesForProviders, chatOptions, cancellationToken).GetAsyncEnumerator(cancellationToken);
         }
         catch (Exception ex)
         {
-            await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessages, continuationToken), chatHistoryProviderMessages, aiContextProviderMessages, chatOptions, cancellationToken).ConfigureAwait(false);
-            await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessages, continuationToken), aiContextProviderMessages, cancellationToken).ConfigureAwait(false);
+            await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessagesForProviders, continuationToken), chatOptions, cancellationToken).ConfigureAwait(false);
+            await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessagesForProviders, continuationToken), cancellationToken).ConfigureAwait(false);
             throw;
         }
 
@@ -246,8 +245,8 @@ public sealed partial class ChatClientAgent : AIAgent
         }
         catch (Exception ex)
         {
-            await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessages, continuationToken), chatHistoryProviderMessages, aiContextProviderMessages, chatOptions, cancellationToken).ConfigureAwait(false);
-            await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessages, continuationToken), aiContextProviderMessages, cancellationToken).ConfigureAwait(false);
+            await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessagesForProviders, continuationToken), chatOptions, cancellationToken).ConfigureAwait(false);
+            await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessagesForProviders, continuationToken), cancellationToken).ConfigureAwait(false);
             throw;
         }
 
@@ -273,8 +272,8 @@ public sealed partial class ChatClientAgent : AIAgent
             }
             catch (Exception ex)
             {
-                await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessages, continuationToken), chatHistoryProviderMessages, aiContextProviderMessages, chatOptions, cancellationToken).ConfigureAwait(false);
-                await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessages, continuationToken), aiContextProviderMessages, cancellationToken).ConfigureAwait(false);
+                await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessagesForProviders, continuationToken), chatOptions, cancellationToken).ConfigureAwait(false);
+                await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, GetInputMessages(inputMessagesForProviders, continuationToken), cancellationToken).ConfigureAwait(false);
                 throw;
             }
         }
@@ -286,10 +285,10 @@ public sealed partial class ChatClientAgent : AIAgent
         await this.UpdateSessionWithTypeAndConversationIdAsync(safeSession, chatResponse.ConversationId, cancellationToken).ConfigureAwait(false);
 
         // To avoid inconsistent state we only notify the session of the input messages if no error occurs after the initial request.
-        await this.NotifyChatHistoryProviderOfNewMessagesAsync(safeSession, GetInputMessages(inputMessages, continuationToken), chatHistoryProviderMessages, aiContextProviderMessages, chatResponse.Messages, chatOptions, cancellationToken).ConfigureAwait(false);
+        await this.NotifyChatHistoryProviderOfNewMessagesAsync(safeSession, GetInputMessages(inputMessagesForProviders, continuationToken), chatResponse.Messages, chatOptions, cancellationToken).ConfigureAwait(false);
 
         // Notify the AIContextProvider of all new messages.
-        await this.NotifyAIContextProviderOfSuccessAsync(safeSession, GetInputMessages(inputMessages, continuationToken), aiContextProviderMessages, chatResponse.Messages, cancellationToken).ConfigureAwait(false);
+        await this.NotifyAIContextProviderOfSuccessAsync(safeSession, GetInputMessages(inputMessagesForProviders, continuationToken), chatResponse.Messages, cancellationToken).ConfigureAwait(false);
     }
 
     /// <inheritdoc/>
@@ -433,9 +432,8 @@ public sealed partial class ChatClientAgent : AIAgent
 
         (ChatClientAgentSession safeSession,
          ChatOptions? chatOptions,
+         List<ChatMessage> inputMessagesForProviders,
          List<ChatMessage> inputMessagesForChatClient,
-         IList<ChatMessage>? aiContextProviderMessages,
-         IList<ChatMessage>? chatHistoryProviderMessages,
          ChatClientAgentContinuationToken? _) =
             await this.PrepareSessionAndMessagesAsync(session, inputMessages, options, cancellationToken).ConfigureAwait(false);
 
@@ -455,8 +453,8 @@ public sealed partial class ChatClientAgent : AIAgent
         }
         catch (Exception ex)
         {
-            await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, inputMessages, chatHistoryProviderMessages, aiContextProviderMessages, chatOptions, cancellationToken).ConfigureAwait(false);
-            await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, inputMessages, aiContextProviderMessages, cancellationToken).ConfigureAwait(false);
+            await this.NotifyChatHistoryProviderOfFailureAsync(safeSession, ex, inputMessagesForProviders, chatOptions, cancellationToken).ConfigureAwait(false);
+            await this.NotifyAIContextProviderOfFailureAsync(safeSession, ex, inputMessagesForProviders, cancellationToken).ConfigureAwait(false);
             throw;
         }
 
@@ -473,10 +471,10 @@ public sealed partial class ChatClientAgent : AIAgent
         }
 
         // Only notify the session of new messages if the chatResponse was successful to avoid inconsistent message state in the session.
-        await this.NotifyChatHistoryProviderOfNewMessagesAsync(safeSession, inputMessages, chatHistoryProviderMessages, aiContextProviderMessages, chatResponse.Messages, chatOptions, cancellationToken).ConfigureAwait(false);
+        await this.NotifyChatHistoryProviderOfNewMessagesAsync(safeSession, inputMessagesForProviders, chatResponse.Messages, chatOptions, cancellationToken).ConfigureAwait(false);
 
         // Notify the AIContextProvider of all new messages.
-        await this.NotifyAIContextProviderOfSuccessAsync(safeSession, inputMessages, aiContextProviderMessages, chatResponse.Messages, cancellationToken).ConfigureAwait(false);
+        await this.NotifyAIContextProviderOfSuccessAsync(safeSession, inputMessagesForProviders, chatResponse.Messages, cancellationToken).ConfigureAwait(false);
 
         var agentResponse = agentResponseFactoryFunc(chatResponse);
 
@@ -491,13 +489,12 @@ public sealed partial class ChatClientAgent : AIAgent
     private async Task NotifyAIContextProviderOfSuccessAsync(
         ChatClientAgentSession session,
         IEnumerable<ChatMessage> inputMessages,
-        IList<ChatMessage>? aiContextProviderMessages,
         IEnumerable<ChatMessage> responseMessages,
         CancellationToken cancellationToken)
     {
         if (session.AIContextProvider is not null)
         {
-            await session.AIContextProvider.InvokedAsync(new(this, session, inputMessages, aiContextProviderMessages) { ResponseMessages = responseMessages },
+            await session.AIContextProvider.InvokedAsync(new(this, session, inputMessages) { ResponseMessages = responseMessages },
                 cancellationToken).ConfigureAwait(false);
         }
     }
@@ -509,12 +506,11 @@ public sealed partial class ChatClientAgent : AIAgent
         ChatClientAgentSession session,
         Exception ex,
         IEnumerable<ChatMessage> inputMessages,
-        IList<ChatMessage>? aiContextProviderMessages,
         CancellationToken cancellationToken)
     {
         if (session.AIContextProvider is not null)
         {
-            await session.AIContextProvider.InvokedAsync(new(this, session, inputMessages, aiContextProviderMessages) { InvokeException = ex },
+            await session.AIContextProvider.InvokedAsync(new(this, session, inputMessages) { InvokeException = ex },
                 cancellationToken).ConfigureAwait(false);
         }
     }
@@ -683,9 +679,8 @@ public sealed partial class ChatClientAgent : AIAgent
         <(
             ChatClientAgentSession AgentSession,
             ChatOptions? ChatOptions,
+            List<ChatMessage> inputMessagesForProviders,
             List<ChatMessage> InputMessagesForChatClient,
-            IList<ChatMessage>? AIContextProviderMessages,
-            IList<ChatMessage>? ChatHistoryProviderMessages,
             ChatClientAgentContinuationToken? ContinuationToken
         )> PrepareSessionAndMessagesAsync(
         AgentSession? session,
@@ -714,9 +709,8 @@ public sealed partial class ChatClientAgent : AIAgent
             throw new InvalidOperationException("Input messages are not allowed when continuing a background response using a continuation token.");
         }
 
+        List<ChatMessage> inputMessagesForProviders = [];
         List<ChatMessage> inputMessagesForChatClient = [];
-        IList<ChatMessage>? aiContextProviderMessages = null;
-        IList<ChatMessage>? chatHistoryProviderMessages = null;
 
         // Populate the session messages only if we are not continuing an existing response as it's not allowed
         if (chatOptions?.ContinuationToken is null)
@@ -729,10 +723,10 @@ public sealed partial class ChatClientAgent : AIAgent
                 var invokingContext = new ChatHistoryProvider.InvokingContext(this, typedSession, inputMessages);
                 var providerMessages = await chatHistoryProvider.InvokingAsync(invokingContext, cancellationToken).ConfigureAwait(false);
                 inputMessagesForChatClient.AddRange(providerMessages);
-                chatHistoryProviderMessages = providerMessages as IList<ChatMessage> ?? providerMessages.ToList();
             }
 
             // Add the input messages before getting context from AIContextProvider.
+            inputMessagesForProviders.AddRange(inputMessages);
             inputMessagesForChatClient.AddRange(inputMessages);
 
             // If we have an AIContextProvider, we should get context from it, and update our
@@ -743,8 +737,8 @@ public sealed partial class ChatClientAgent : AIAgent
                 var aiContext = await typedSession.AIContextProvider.InvokingAsync(invokingContext, cancellationToken).ConfigureAwait(false);
                 if (aiContext.Messages is { Count: > 0 })
                 {
+                    inputMessagesForProviders.AddRange(aiContext.Messages);
                     inputMessagesForChatClient.AddRange(aiContext.Messages);
-                    aiContextProviderMessages = aiContext.Messages;
                 }
 
                 if (aiContext.Tools is { Count: > 0 })
@@ -783,7 +777,7 @@ public sealed partial class ChatClientAgent : AIAgent
             chatOptions.ConversationId = typedSession.ConversationId;
         }
 
-        return (typedSession, chatOptions, inputMessagesForChatClient, aiContextProviderMessages, chatHistoryProviderMessages, continuationToken);
+        return (typedSession, chatOptions, inputMessagesForProviders, inputMessagesForChatClient, continuationToken);
     }
 
     private async Task UpdateSessionWithTypeAndConversationIdAsync(ChatClientAgentSession session, string? responseConversationId, CancellationToken cancellationToken)
@@ -816,8 +810,6 @@ public sealed partial class ChatClientAgent : AIAgent
         ChatClientAgentSession session,
         Exception ex,
         IEnumerable<ChatMessage> requestMessages,
-        IEnumerable<ChatMessage>? chatHistoryProviderMessages,
-        IEnumerable<ChatMessage>? aiContextProviderMessages,
         ChatOptions? chatOptions,
         CancellationToken cancellationToken)
     {
@@ -827,9 +819,8 @@ public sealed partial class ChatClientAgent : AIAgent
         // If we don't have one, it means that the chat history is service managed and the underlying service is responsible for storing messages.
         if (provider is not null)
         {
-            var invokedContext = new ChatHistoryProvider.InvokedContext(this, session, requestMessages, chatHistoryProviderMessages!)
+            var invokedContext = new ChatHistoryProvider.InvokedContext(this, session, requestMessages)
             {
-                AIContextProviderMessages = aiContextProviderMessages,
                 InvokeException = ex
             };
 
@@ -842,8 +833,6 @@ public sealed partial class ChatClientAgent : AIAgent
     private Task NotifyChatHistoryProviderOfNewMessagesAsync(
         ChatClientAgentSession session,
         IEnumerable<ChatMessage> requestMessages,
-        IEnumerable<ChatMessage>? chatHistoryProviderMessages,
-        IEnumerable<ChatMessage>? aiContextProviderMessages,
         IEnumerable<ChatMessage> responseMessages,
         ChatOptions? chatOptions,
         CancellationToken cancellationToken)
@@ -854,9 +843,8 @@ public sealed partial class ChatClientAgent : AIAgent
         // If we don't have one, it means that the chat history is service managed and the underlying service is responsible for storing messages.
         if (provider is not null)
         {
-            var invokedContext = new ChatHistoryProvider.InvokedContext(this, session, requestMessages, chatHistoryProviderMessages!)
+            var invokedContext = new ChatHistoryProvider.InvokedContext(this, session, requestMessages)
             {
-                AIContextProviderMessages = aiContextProviderMessages,
                 ResponseMessages = responseMessages
             };
             return provider.InvokedAsync(invokedContext, cancellationToken).AsTask();

dotnet/src/Microsoft.Agents.AI/Memory/ChatHistoryMemoryProvider.cs

@@ -25,8 +25,8 @@ namespace Microsoft.Agents.AI;
 /// abstractions to work with any compatible vector store implementation.
 /// </para>
 /// <para>
-/// Messages are stored during the <see cref="InvokedAsync"/> method and retrieved during the
-/// <see cref="InvokingAsync"/> method using semantic similarity search.
+/// Messages are stored during the <see cref="InvokedCoreAsync"/> method and retrieved during the
+/// <see cref="InvokingCoreAsync"/> method using semantic similarity search.
 /// </para>
 /// <para>
 /// Behavior is configurable through <see cref="ChatHistoryMemoryProviderOptions"/>. When
@@ -175,7 +175,7 @@ public sealed class ChatHistoryMemoryProvider : AIContextProvider, IDisposable
     }
 
     /// <inheritdoc />
-    public override async ValueTask<AIContext> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask<AIContext> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default)
     {
         _ = Throw.IfNull(context);
 
@@ -189,6 +189,7 @@ public sealed class ChatHistoryMemoryProvider : AIContextProvider, IDisposable
         {
             // Get the text from the current request messages
             var requestText = string.Join("\n", context.RequestMessages
+                .Where(m => m.GetAgentRequestMessageSource() == AgentRequestMessageSourceType.External)
                 .Where(m => m != null && !string.IsNullOrWhiteSpace(m.Text))
                 .Select(m => m.Text));
 
@@ -228,7 +229,7 @@ public sealed class ChatHistoryMemoryProvider : AIContextProvider, IDisposable
     }
 
     /// <inheritdoc />
-    public override async ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
     {
         _ = Throw.IfNull(context);
 
@@ -244,6 +245,7 @@ public sealed class ChatHistoryMemoryProvider : AIContextProvider, IDisposable
             var collection = await this.EnsureCollectionExistsAsync(cancellationToken).ConfigureAwait(false);
 
             List<Dictionary<string, object?>> itemsToStore = context.RequestMessages
+                .Where(m => m.GetAgentRequestMessageSource() == AgentRequestMessageSourceType.External)
                 .Concat(context.ResponseMessages ?? [])
                 .Select(message => new Dictionary<string, object?>
                 {

dotnet/src/Microsoft.Agents.AI/TextSearchProvider.cs

@@ -107,7 +107,7 @@ public sealed class TextSearchProvider : AIContextProvider
     }
 
     /// <inheritdoc />
-    public override async ValueTask<AIContext> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    protected override async ValueTask<AIContext> InvokingCoreAsync(InvokingContext context, CancellationToken cancellationToken = default)
     {
         if (this._searchTime != TextSearchProviderOptions.TextSearchBehavior.BeforeAIInvoke)
         {
@@ -117,7 +117,9 @@ public sealed class TextSearchProvider : AIContextProvider
 
         // Aggregate text from memory + current request messages.
         var sbInput = new StringBuilder();
-        var requestMessagesText = context.RequestMessages.Where(x => !string.IsNullOrWhiteSpace(x?.Text)).Select(x => x.Text);
+        var requestMessagesText = context.RequestMessages
+            .Where(m => m.GetAgentRequestMessageSource() == AgentRequestMessageSourceType.External)
+            .Where(x => !string.IsNullOrWhiteSpace(x?.Text)).Select(x => x.Text);
         foreach (var messageText in this._recentMessagesText.Concat(requestMessagesText))
         {
             if (sbInput.Length > 0)
@@ -166,7 +168,7 @@ public sealed class TextSearchProvider : AIContextProvider
     }
 
     /// <inheritdoc />
-    public override ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    protected override ValueTask InvokedCoreAsync(InvokedContext context, CancellationToken cancellationToken = default)
     {
         int limit = this._recentMessageMemoryLimit;
         if (limit <= 0)
@@ -180,6 +182,7 @@ public sealed class TextSearchProvider : AIContextProvider
         }
 
         var messagesText = context.RequestMessages
+            .Where(m => m.GetAgentRequestMessageSource() == AgentRequestMessageSourceType.External)
             .Concat(context.ResponseMessages ?? [])
             .Where(m =>
                 this._recentMessageRolesIncluded.Contains(m.Role) &&