Merge branch 'main' into feature-foundry-agents

2026-06-16 21:04:09 +08:00 · 2025-11-07 09:14:33 -08:00
parent 4cbde55243 00b67e191b
commit 91e63df616
50 changed files with 3808 additions and 284 deletions
@@ -18,6 +18,21 @@ namespace Microsoft.AspNetCore.Builder;
 /// </summary>
 public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
 {
+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agentBuilder">The configuration builder for <see cref="AIAgent"/>.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    /// <remarks>
+    /// This method can be used to access A2A agents that support the
+    /// <see href="https://github.com/a2aproject/A2A/blob/main/docs/topics/agent-discovery.md#2-curated-registries-catalog-based-discovery">Curated Registries (Catalog-Based Discovery)</see>
+    /// discovery mechanism.
+    /// </remarks>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string path)
+        => endpoints.MapA2A(agentBuilder, path, _ => { });
+
    /// <summary>
    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
    /// </summary>
@@ -28,6 +43,25 @@ public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path)
        => endpoints.MapA2A(agentName, path, _ => { });

+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agentBuilder">The configuration builder for <see cref="AIAgent"/>.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="configureTaskManager">The callback to configure <see cref="ITaskManager"/>.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    /// <remarks>
+    /// This method can be used to access A2A agents that support the
+    /// <see href="https://github.com/a2aproject/A2A/blob/main/docs/topics/agent-discovery.md#2-curated-registries-catalog-based-discovery">Curated Registries (Catalog-Based Discovery)</see>
+    /// discovery mechanism.
+    /// </remarks>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string path, Action<ITaskManager> configureTaskManager)
+    {
+        ArgumentNullException.ThrowIfNull(agentBuilder);
+        return endpoints.MapA2A(agentBuilder.Name, path, configureTaskManager);
+    }
+
    /// <summary>
    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
    /// </summary>
@@ -38,10 +72,27 @@ public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, Action<ITaskManager> configureTaskManager)
    {
+        ArgumentNullException.ThrowIfNull(endpoints);
        var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentName);
        return endpoints.MapA2A(agent, path, configureTaskManager);
    }

+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agentBuilder">The configuration builder for <see cref="AIAgent"/>.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="agentCard">Agent card info to return on query.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    /// <remarks>
+    /// This method can be used to access A2A agents that support the
+    /// <see href="https://github.com/a2aproject/A2A/blob/main/docs/topics/agent-discovery.md#2-curated-registries-catalog-based-discovery">Curated Registries (Catalog-Based Discovery)</see>
+    /// discovery mechanism.
+    /// </remarks>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string path, AgentCard agentCard)
+        => endpoints.MapA2A(agentBuilder, path, agentCard, _ => { });
+
    /// <summary>
    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
    /// </summary>
@@ -58,6 +109,26 @@ public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentCard agentCard)
        => endpoints.MapA2A(agentName, path, agentCard, _ => { });

+    /// <summary>
+    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the A2A endpoints to.</param>
+    /// <param name="agentBuilder">The configuration builder for <see cref="AIAgent"/>.</param>
+    /// <param name="path">The route group to use for A2A endpoints.</param>
+    /// <param name="agentCard">Agent card info to return on query.</param>
+    /// <param name="configureTaskManager">The callback to configure <see cref="ITaskManager"/>.</param>
+    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
+    /// <remarks>
+    /// This method can be used to access A2A agents that support the
+    /// <see href="https://github.com/a2aproject/A2A/blob/main/docs/topics/agent-discovery.md#2-curated-registries-catalog-based-discovery">Curated Registries (Catalog-Based Discovery)</see>
+    /// discovery mechanism.
+    /// </remarks>
+    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string path, AgentCard agentCard, Action<ITaskManager> configureTaskManager)
+    {
+        ArgumentNullException.ThrowIfNull(agentBuilder);
+        return endpoints.MapA2A(agentBuilder.Name, path, agentCard, configureTaskManager);
+    }
+
    /// <summary>
    /// Attaches A2A (Agent2Agent) communication capabilities via Message processing to the specified web application.
    /// </summary>
@@ -74,6 +145,7 @@ public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
    /// </remarks>
    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, string agentName, string path, AgentCard agentCard, Action<ITaskManager> configureTaskManager)
    {
+        ArgumentNullException.ThrowIfNull(endpoints);
        var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentName);
        return endpoints.MapA2A(agent, path, agentCard, configureTaskManager);
    }
@@ -98,6 +170,9 @@ public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
    /// <returns>Configured <see cref="ITaskManager"/> for A2A integration.</returns>
    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, Action<ITaskManager> configureTaskManager)
    {
+        ArgumentNullException.ThrowIfNull(endpoints);
+        ArgumentNullException.ThrowIfNull(agent);
+
        var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
        var agentThreadStore = endpoints.ServiceProvider.GetKeyedService<AgentThreadStore>(agent.Name);
        var taskManager = agent.MapA2A(loggerFactory: loggerFactory, agentThreadStore: agentThreadStore);
@@ -139,6 +214,9 @@ public static class MicrosoftAgentAIHostingA2AEndpointRouteBuilderExtensions
    /// </remarks>
    public static IEndpointConventionBuilder MapA2A(this IEndpointRouteBuilder endpoints, AIAgent agent, string path, AgentCard agentCard, Action<ITaskManager> configureTaskManager)
    {
+        ArgumentNullException.ThrowIfNull(endpoints);
+        ArgumentNullException.ThrowIfNull(agent);
+
        var loggerFactory = endpoints.ServiceProvider.GetRequiredService<ILoggerFactory>();
        var agentThreadStore = endpoints.ServiceProvider.GetKeyedService<AgentThreadStore>(agent.Name);
        var taskManager = agent.MapA2A(agentCard: agentCard, agentThreadStore: agentThreadStore, loggerFactory: loggerFactory);
@@ -29,6 +29,6 @@
  
  <ItemGroup>
    <InternalsVisibleTo Include="AgentWebChat.Web" />
-    <InternalsVisibleTo Include="Microsoft.Agents.AI.Hosting.A2A.Tests" />
+    <InternalsVisibleTo Include="Microsoft.Agents.AI.Hosting.A2A.UnitTests" />
  </ItemGroup>
 </Project>
@@ -3,6 +3,7 @@
 using System;
 using System.Diagnostics.CodeAnalysis;
 using Microsoft.Agents.AI;
+using Microsoft.Agents.AI.Hosting;
 using Microsoft.Agents.AI.Hosting.OpenAI;
 using Microsoft.Agents.AI.Hosting.OpenAI.Conversations;
 using Microsoft.Agents.AI.Hosting.OpenAI.Responses;
@@ -17,6 +18,29 @@ namespace Microsoft.AspNetCore.Builder;
 /// </summary>
 public static partial class MicrosoftAgentAIHostingOpenAIEndpointRouteBuilderExtensions
 {
+    /// <summary>
+    /// Maps OpenAI Responses API endpoints to the specified <see cref="IEndpointRouteBuilder"/> for the given <see cref="IHostedAgentBuilder"/>.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the OpenAI Responses endpoints to.</param>
+    /// <param name="agentBuilder">The builder for <see cref="AIAgent"/> to map the OpenAI Responses endpoints for.</param>
+    public static IEndpointConventionBuilder MapOpenAIResponses(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder)
+        => MapOpenAIResponses(endpoints, agentBuilder, path: null);
+
+    /// <summary>
+    /// Maps OpenAI Responses API endpoints to the specified <see cref="IEndpointRouteBuilder"/> for the given <see cref="IHostedAgentBuilder"/>.
+    /// </summary>
+    /// <param name="endpoints">The <see cref="IEndpointRouteBuilder"/> to add the OpenAI Responses endpoints to.</param>
+    /// <param name="agentBuilder">The builder for <see cref="AIAgent"/> to map the OpenAI Responses endpoints for.</param>
+    /// <param name="path">Custom route path for the OpenAI Responses endpoint.</param>
+    public static IEndpointConventionBuilder MapOpenAIResponses(this IEndpointRouteBuilder endpoints, IHostedAgentBuilder agentBuilder, string? path)
+    {
+        ArgumentNullException.ThrowIfNull(endpoints);
+        ArgumentNullException.ThrowIfNull(agentBuilder);
+
+        var agent = endpoints.ServiceProvider.GetRequiredKeyedService<AIAgent>(agentBuilder.Name);
+        return MapOpenAIResponses(endpoints, agent, path);
+    }
+
    /// <summary>
    /// Maps OpenAI Responses API endpoints to the specified <see cref="IEndpointRouteBuilder"/> for the given <see cref="AIAgent"/>.
    /// </summary>
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.

 using System;
+using System.Collections.Generic;
 using System.Linq;
 using Microsoft.Agents.AI.Hosting.Local;
 using Microsoft.Extensions.AI;
@@ -29,7 +30,8 @@ public static class AgentHostingServiceCollectionExtensions
        return services.AddAIAgent(name, (sp, key) =>
        {
            var chatClient = sp.GetRequiredService<IChatClient>();
-            return new ChatClientAgent(chatClient, instructions, key);
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions, key, tools: tools);
        });
    }

@@ -46,7 +48,11 @@ public static class AgentHostingServiceCollectionExtensions
    {
        Throw.IfNull(services);
        Throw.IfNullOrEmpty(name);
-        return services.AddAIAgent(name, (sp, key) => new ChatClientAgent(chatClient, instructions, key));
+        return services.AddAIAgent(name, (sp, key) =>
+        {
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions, key, tools: tools);
+        });
    }

    /// <summary>
@@ -65,7 +71,8 @@ public static class AgentHostingServiceCollectionExtensions
        return services.AddAIAgent(name, (sp, key) =>
        {
            var chatClient = chatClientServiceKey is null ? sp.GetRequiredService<IChatClient>() : sp.GetRequiredKeyedService<IChatClient>(chatClientServiceKey);
-            return new ChatClientAgent(chatClient, instructions, key);
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions, key, tools: tools);
        });
    }

@@ -86,7 +93,8 @@ public static class AgentHostingServiceCollectionExtensions
        return services.AddAIAgent(name, (sp, key) =>
        {
            var chatClient = chatClientServiceKey is null ? sp.GetRequiredService<IChatClient>() : sp.GetRequiredKeyedService<IChatClient>(chatClientServiceKey);
-            return new ChatClientAgent(chatClient, instructions: instructions, name: key, description: description);
+            var tools = GetRegisteredToolsForAgent(sp, name);
+            return new ChatClientAgent(chatClient, instructions: instructions, name: key, description: description, tools: tools);
        });
    }

@@ -142,4 +150,10 @@ public static class AgentHostingServiceCollectionExtensions
        services.Add(ServiceDescriptor.Singleton(agentHostBuilderContext));
        services.AddSingleton<AgentCatalog, LocalAgentCatalog>();
    }
+
+    private static IList<AITool> GetRegisteredToolsForAgent(IServiceProvider serviceProvider, string agentName)
+    {
+        var registry = serviceProvider.GetService<LocalAgentToolRegistry>();
+        return registry?.GetTools(agentName) ?? [];
+    }
 }
@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.

 using System;
-using System.Collections.Generic;
 using System.Linq;
 using Microsoft.Agents.AI.Hosting.Local;
 using Microsoft.Agents.AI.Workflows;
@@ -16,46 +15,6 @@ namespace Microsoft.Agents.AI.Hosting;
 /// </summary>
 public static class HostApplicationBuilderWorkflowExtensions
 {
-    /// <summary>
-    /// Registers a concurrent workflow that executes multiple agents in parallel.
-    /// </summary>
-    /// <param name="builder">The <see cref="IHostApplicationBuilder"/> to configure.</param>
-    /// <param name="name">The unique name for the workflow.</param>
-    /// <param name="agentBuilders">A collection of <see cref="IHostedAgentBuilder"/> instances representing agents to execute concurrently.</param>
-    /// <returns>An <see cref="IHostedWorkflowBuilder"/> that can be used to further configure the workflow.</returns>
-    /// <exception cref="ArgumentNullException">Thrown when <paramref name="builder"/>, <paramref name="name"/>, or <paramref name="agentBuilders"/> is null.</exception>
-    /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> or <paramref name="agentBuilders"/> is empty.</exception>
-    public static IHostedWorkflowBuilder AddConcurrentWorkflow(this IHostApplicationBuilder builder, string name, IEnumerable<IHostedAgentBuilder> agentBuilders)
-    {
-        Throw.IfNullOrEmpty(agentBuilders);
-
-        return builder.AddWorkflow(name, (sp, key) =>
-        {
-            var agents = agentBuilders.Select(ab => sp.GetRequiredKeyedService<AIAgent>(ab.Name));
-            return AgentWorkflowBuilder.BuildConcurrent(workflowName: name, agents: agents);
-        });
-    }
-
-    /// <summary>
-    /// Registers a sequential workflow that executes agents in a specific order.
-    /// </summary>
-    /// <param name="builder">The <see cref="IHostApplicationBuilder"/> to configure.</param>
-    /// <param name="name">The unique name for the workflow.</param>
-    /// <param name="agentBuilders">A collection of <see cref="IHostedAgentBuilder"/> instances representing agents to execute in sequence.</param>
-    /// <returns>An <see cref="IHostedWorkflowBuilder"/> that can be used to further configure the workflow.</returns>
-    /// <exception cref="ArgumentNullException">Thrown when <paramref name="builder"/>, <paramref name="name"/>, or <paramref name="agentBuilders"/> is null.</exception>
-    /// <exception cref="ArgumentException">Thrown when <paramref name="name"/> or <paramref name="agentBuilders"/> is empty.</exception>
-    public static IHostedWorkflowBuilder AddSequentialWorkflow(this IHostApplicationBuilder builder, string name, IEnumerable<IHostedAgentBuilder> agentBuilders)
-    {
-        Throw.IfNullOrEmpty(agentBuilders);
-
-        return builder.AddWorkflow(name, (sp, key) =>
-        {
-            var agents = agentBuilders.Select(ab => sp.GetRequiredKeyedService<AIAgent>(ab.Name));
-            return AgentWorkflowBuilder.BuildSequential(workflowName: name, agents: agents);
-        });
-    }
-
    /// <summary>
    /// Registers a custom workflow using a factory delegate.
    /// </summary>
@@ -1,6 +1,9 @@
 // Copyright (c) Microsoft. All rights reserved.

 using System;
+using System.Linq;
+using Microsoft.Agents.AI.Hosting.Local;
+using Microsoft.Extensions.AI;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Shared.Diagnostics;

@@ -59,4 +62,52 @@ public static class HostedAgentBuilderExtensions
        });
        return builder;
    }
+
+    /// <summary>
+    /// Adds an AI tool to an agent being configured with the service collection.
+    /// </summary>
+    /// <param name="builder">The hosted agent builder.</param>
+    /// <param name="tool">The AI tool to add to the agent.</param>
+    /// <returns>The same <see cref="IHostedAgentBuilder"/> instance so that additional calls can be chained.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="builder"/> or <paramref name="tool"/> is <see langword="null"/>.</exception>
+    public static IHostedAgentBuilder WithAITool(this IHostedAgentBuilder builder, AITool tool)
+    {
+        Throw.IfNull(builder);
+        Throw.IfNull(tool);
+
+        var agentName = builder.Name;
+        var services = builder.ServiceCollection;
+
+        // Get or create the agent tool registry
+        var descriptor = services.FirstOrDefault(sd => !sd.IsKeyedService && sd.ServiceType.Equals(typeof(LocalAgentToolRegistry)));
+        if (descriptor?.ImplementationInstance is not LocalAgentToolRegistry toolRegistry)
+        {
+            toolRegistry = new();
+            services.Add(ServiceDescriptor.Singleton(toolRegistry));
+        }
+
+        toolRegistry.AddTool(agentName, tool);
+
+        return builder;
+    }
+
+    /// <summary>
+    /// Adds multiple AI tools to an agent being configured with the service collection.
+    /// </summary>
+    /// <param name="builder">The hosted agent builder.</param>
+    /// <param name="tools">The collection of AI tools to add to the agent.</param>
+    /// <returns>The same <see cref="IHostedAgentBuilder"/> instance so that additional calls can be chained.</returns>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="builder"/> or <paramref name="tools"/> is <see langword="null"/>.</exception>
+    public static IHostedAgentBuilder WithAITools(this IHostedAgentBuilder builder, params AITool[] tools)
+    {
+        Throw.IfNull(builder);
+        Throw.IfNull(tools);
+
+        foreach (var tool in tools)
+        {
+            builder.WithAITool(tool);
+        }
+
+        return builder;
+    }
 }
@@ -0,0 +1,27 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI.Hosting.Local;
+
+internal sealed class LocalAgentToolRegistry
+{
+    private readonly Dictionary<string, List<AITool>> _toolsByAgentName = new();
+
+    public void AddTool(string agentName, AITool tool)
+    {
+        if (!this._toolsByAgentName.TryGetValue(agentName, out var tools))
+        {
+            tools = [];
+            this._toolsByAgentName[agentName] = tools;
+        }
+
+        tools.Add(tool);
+    }
+
+    public IList<AITool> GetTools(string agentName)
+    {
+        return this._toolsByAgentName.TryGetValue(agentName, out var tools) ? tools : [];
+    }
+}
@@ -153,7 +153,7 @@ public sealed class Mem0Provider : AIContextProvider
            if (this._logger is not null)
            {
                this._logger.LogInformation(
-                    "Mem0AIContextProvider: Retrieved {Count} memories. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'",
+                    "Mem0AIContextProvider: Retrieved {Count} memories. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
                    memories.Count,
                    this._searchScope.ApplicationId,
                    this._searchScope.AgentId,
@@ -162,7 +162,7 @@ public sealed class Mem0Provider : AIContextProvider
                if (outputMessageText is not null)
                {
                    this._logger.LogTrace(
-                        "Mem0AIContextProvider: Search Results\nInput:{Input}\nOutput:{MessageText}\nApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'",
+                        "Mem0AIContextProvider: Search Results\nInput:{Input}\nOutput:{MessageText}\nApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
                        queryText,
                        outputMessageText,
                        this._searchScope.ApplicationId,
@@ -185,7 +185,7 @@ public sealed class Mem0Provider : AIContextProvider
        {
            this._logger?.LogError(
                ex,
-                "Mem0AIContextProvider: Failed to search Mem0 for memories due to error. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'",
+                "Mem0AIContextProvider: Failed to search Mem0 for memories due to error. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
                this._searchScope.ApplicationId,
                this._searchScope.AgentId,
                this._searchScope.ThreadId,
@@ -211,7 +211,7 @@ public sealed class Mem0Provider : AIContextProvider
        {
            this._logger?.LogError(
                ex,
-                "Mem0AIContextProvider: Failed to send messages to Mem0 due to error. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'",
+                "Mem0AIContextProvider: Failed to send messages to Mem0 due to error. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
                this._storageScope.ApplicationId,
                this._storageScope.AgentId,
                this._storageScope.ThreadId,
@@ -68,6 +68,7 @@ internal static partial class AgentJsonUtilities
    // Agent abstraction types
    [JsonSerializable(typeof(ChatClientAgentThread.ThreadState))]
    [JsonSerializable(typeof(TextSearchProvider.TextSearchProviderState))]
+    [JsonSerializable(typeof(ChatHistoryMemoryProvider.ChatHistoryMemoryProviderState))]

    [ExcludeFromCodeCoverage]
    internal sealed partial class JsonContext : JsonSerializerContext;
@@ -166,8 +166,8 @@ public class ChatClientAgentThread : AgentThread
        var state = new ThreadState
        {
            ConversationId = this.ConversationId,
-            StoreState = storeState,
-            AIContextProviderState = aiContextProviderState
+            StoreState = storeState is { ValueKind: not JsonValueKind.Undefined } ? storeState : null,
+            AIContextProviderState = aiContextProviderState is { ValueKind: not JsonValueKind.Undefined } ? aiContextProviderState : null,
        };

        return JsonSerializer.SerializeToElement(state, AgentJsonUtilities.DefaultOptions.GetTypeInfo(typeof(ThreadState)));
@@ -0,0 +1,483 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.AI;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.VectorData;
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// A context provider that stores all chat history in a vector store and is able to
+/// retrieve related chat history later to augment the current conversation.
+/// </summary>
+/// <remarks>
+/// <para>
+/// This provider stores chat messages in a vector store and retrieves relevant previous messages
+/// to provide as context during agent invocations. It uses the VectorStore and VectorStoreCollection
+/// 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.
+/// </para>
+/// <para>
+/// Behavior is configurable through <see cref="ChatHistoryMemoryProviderOptions"/>. When
+/// <see cref="ChatHistoryMemoryProviderOptions.SearchBehavior.OnDemandFunctionCalling"/> is selected the provider
+/// exposes a function tool that the model can invoke to retrieve relevant memories on demand instead of
+/// injecting them automatically on each invocation.
+/// </para>
+/// </remarks>
+public sealed class ChatHistoryMemoryProvider : AIContextProvider, IDisposable
+{
+    private const string DefaultContextPrompt = "## Memories\nConsider the following memories when answering user questions:";
+    private const int DefaultMaxResults = 3;
+    private const string DefaultFunctionToolName = "Search";
+    private const string DefaultFunctionToolDescription = "Allows searching for related previous chat history to help answer the user question.";
+
+    private readonly VectorStore _vectorStore;
+    private readonly VectorStoreCollection<object, Dictionary<string, object?>> _collection;
+    private readonly int _maxResults;
+    private readonly string _contextPrompt;
+    private readonly ChatHistoryMemoryProviderOptions.SearchBehavior _searchTime;
+    private readonly AITool[] _tools;
+    private readonly ILogger<ChatHistoryMemoryProvider>? _logger;
+
+    private readonly ChatHistoryMemoryProviderScope _storageScope;
+    private readonly ChatHistoryMemoryProviderScope _searchScope;
+
+    private bool _collectionInitialized;
+    private readonly SemaphoreSlim _initializationLock = new(1, 1);
+    private bool _disposedValue;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ChatHistoryMemoryProvider"/> class.
+    /// </summary>
+    /// <param name="vectorStore">The vector store to use for storing and retrieving chat history.</param>
+    /// <param name="collectionName">The name of the collection for storing chat history in the vector store.</param>
+    /// <param name="vectorDimensions">The number of dimensions to use for the chat history vector store embeddings.</param>
+    /// <param name="storageScope">Optional values to scope the chat history storage with.</param>
+    /// <param name="searchScope">Optional values to scope the chat history search with. Where values are null, no filtering is done using those values. Defaults to <paramref name="storageScope"/> if not provided.</param>
+    /// <param name="options">Optional configuration options.</param>
+    /// <param name="loggerFactory">Optional logger factory.</param>
+    /// <exception cref="ArgumentNullException">Thrown when <paramref name="vectorStore"/> is <see langword="null"/>.</exception>
+    public ChatHistoryMemoryProvider(
+        VectorStore vectorStore,
+        string collectionName,
+        int vectorDimensions,
+        ChatHistoryMemoryProviderScope storageScope,
+        ChatHistoryMemoryProviderScope? searchScope = null,
+        ChatHistoryMemoryProviderOptions? options = null,
+        ILoggerFactory? loggerFactory = null)
+        : this(
+            vectorStore,
+            collectionName,
+            vectorDimensions,
+            new ChatHistoryMemoryProviderState
+            {
+                StorageScope = new(Throw.IfNull(storageScope)),
+                SearchScope = searchScope ?? new(storageScope),
+            },
+            options,
+            loggerFactory)
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ChatHistoryMemoryProvider"/> class from previously serialized state.
+    /// </summary>
+    /// <param name="vectorStore">The vector store to use for storing and retrieving chat history.</param>
+    /// <param name="collectionName">The name of the collection for storing chat history in the vector store.</param>
+    /// <param name="vectorDimensions">The number of dimensions to use for the chat history vector store embeddings.</param>
+    /// <param name="serializedState">A <see cref="JsonElement"/> representing the serialized state of the provider.</param>
+    /// <param name="jsonSerializerOptions">Optional settings for customizing the JSON deserialization process.</param>
+    /// <param name="options">Optional configuration options.</param>
+    /// <param name="loggerFactory">Optional logger factory.</param>
+    public ChatHistoryMemoryProvider(
+        VectorStore vectorStore,
+        string collectionName,
+        int vectorDimensions,
+        JsonElement serializedState,
+        JsonSerializerOptions? jsonSerializerOptions = null,
+        ChatHistoryMemoryProviderOptions? options = null,
+        ILoggerFactory? loggerFactory = null)
+        : this(
+            vectorStore,
+            collectionName,
+            vectorDimensions,
+            DeserializeState(serializedState, jsonSerializerOptions),
+            options,
+            loggerFactory)
+    {
+    }
+
+    private ChatHistoryMemoryProvider(
+        VectorStore vectorStore,
+        string collectionName,
+        int vectorDimensions,
+        ChatHistoryMemoryProviderState? state = null,
+        ChatHistoryMemoryProviderOptions? options = null,
+        ILoggerFactory? loggerFactory = null)
+    {
+        this._vectorStore = vectorStore ?? throw new ArgumentNullException(nameof(vectorStore));
+        options ??= new ChatHistoryMemoryProviderOptions();
+        this._maxResults = options.MaxResults.HasValue ? Throw.IfLessThanOrEqual(options.MaxResults.Value, 0) : DefaultMaxResults;
+        this._contextPrompt = options.ContextPrompt ?? DefaultContextPrompt;
+        this._searchTime = options.SearchTime;
+        this._logger = loggerFactory?.CreateLogger<ChatHistoryMemoryProvider>();
+
+        if (state == null || state.StorageScope == null || state.SearchScope == null)
+        {
+            throw new InvalidOperationException($"The {nameof(ChatHistoryMemoryProvider)} state did not contain the required scope properties.");
+        }
+
+        this._storageScope = state.StorageScope;
+        this._searchScope = state.SearchScope;
+
+        // Create on-demand search tool (only used when behavior is OnDemandFunctionCalling)
+        this._tools =
+        [
+            AIFunctionFactory.Create(
+                (Func<string, CancellationToken, Task<string>>)this.SearchTextAsync,
+                name: options.FunctionToolName ?? DefaultFunctionToolName,
+                description: options.FunctionToolDescription ?? DefaultFunctionToolDescription)
+        ];
+
+        // Create a definition so that we can use the dimensions provided at runtime.
+        var definition = new VectorStoreCollectionDefinition
+        {
+            Properties = new List<VectorStoreProperty>
+            {
+                new VectorStoreKeyProperty("Key", typeof(Guid)),
+                new VectorStoreDataProperty("Role", typeof(string)) { IsIndexed = true },
+                new VectorStoreDataProperty("MessageId", typeof(string)) { IsIndexed = true },
+                new VectorStoreDataProperty("AuthorName", typeof(string)),
+                new VectorStoreDataProperty("ApplicationId", typeof(string)) { IsIndexed = true },
+                new VectorStoreDataProperty("AgentId", typeof(string)) { IsIndexed = true },
+                new VectorStoreDataProperty("UserId", typeof(string)) { IsIndexed = true },
+                new VectorStoreDataProperty("ThreadId", typeof(string)) { IsIndexed = true },
+                new VectorStoreDataProperty("Content", typeof(string)) { IsFullTextIndexed = true },
+                new VectorStoreDataProperty("CreatedAt", typeof(string)) { IsIndexed = true },
+                new VectorStoreVectorProperty("ContentEmbedding", typeof(string), Throw.IfLessThan(vectorDimensions, 1))
+            }
+        };
+
+        this._collection = this._vectorStore.GetDynamicCollection(Throw.IfNullOrWhitespace(collectionName), definition);
+    }
+
+    /// <inheritdoc />
+    public override async ValueTask<AIContext> InvokingAsync(InvokingContext context, CancellationToken cancellationToken = default)
+    {
+        _ = Throw.IfNull(context);
+
+        if (this._searchTime == ChatHistoryMemoryProviderOptions.SearchBehavior.OnDemandFunctionCalling)
+        {
+            // Expose search tool for on-demand invocation by the model
+            return new AIContext { Tools = this._tools };
+        }
+
+        try
+        {
+            // Get the text from the current request messages
+            var requestText = string.Join("\n", context.RequestMessages
+                .Where(m => m != null && !string.IsNullOrWhiteSpace(m.Text))
+                .Select(m => m.Text));
+
+            if (string.IsNullOrWhiteSpace(requestText))
+            {
+                return new AIContext();
+            }
+
+            // Search for relevant chat history
+            var contextText = await this.SearchTextAsync(requestText, cancellationToken).ConfigureAwait(false);
+
+            if (string.IsNullOrWhiteSpace(contextText))
+            {
+                return new AIContext();
+            }
+
+            return new AIContext
+            {
+                Messages = [new ChatMessage(ChatRole.User, contextText)]
+            };
+        }
+        catch (Exception ex)
+        {
+            this._logger?.LogError(
+                ex,
+                "ChatHistoryMemoryProvider: Failed to search for chat history due to error. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
+                this._searchScope.ApplicationId,
+                this._searchScope.AgentId,
+                this._searchScope.ThreadId,
+                this._searchScope.UserId);
+            return new AIContext();
+        }
+    }
+
+    /// <inheritdoc />
+    public override async ValueTask InvokedAsync(InvokedContext context, CancellationToken cancellationToken = default)
+    {
+        _ = Throw.IfNull(context);
+
+        // Only store if invocation was successful
+        if (context.InvokeException != null)
+        {
+            return;
+        }
+
+        try
+        {
+            // Ensure the collection is initialized
+            var collection = await this.EnsureCollectionExistsAsync(cancellationToken).ConfigureAwait(false);
+
+            List<Dictionary<string, object?>> itemsToStore = context.RequestMessages
+                .Concat(context.ResponseMessages ?? [])
+                .Select(message => new Dictionary<string, object?>
+                {
+                    ["Key"] = Guid.NewGuid(),
+                    ["Role"] = message.Role.ToString(),
+                    ["MessageId"] = message.MessageId,
+                    ["AuthorName"] = message.AuthorName,
+                    ["ApplicationId"] = this._storageScope?.ApplicationId,
+                    ["AgentId"] = this._storageScope?.AgentId,
+                    ["UserId"] = this._storageScope?.UserId,
+                    ["ThreadId"] = this._storageScope?.ThreadId,
+                    ["Content"] = message.Text,
+                    ["CreatedAt"] = message.CreatedAt?.ToString("O") ?? DateTimeOffset.UtcNow.ToString("O"),
+                    ["ContentEmbedding"] = message.Text,
+                })
+                .ToList();
+
+            if (itemsToStore.Count > 0)
+            {
+                await collection.UpsertAsync(itemsToStore, cancellationToken).ConfigureAwait(false);
+            }
+        }
+        catch (Exception ex)
+        {
+            this._logger?.LogError(
+                ex,
+                "ChatHistoryMemoryProvider: Failed to add messages to chat history vector store due to error. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
+                this._searchScope.ApplicationId,
+                this._searchScope.AgentId,
+                this._searchScope.ThreadId,
+                this._searchScope.UserId);
+        }
+    }
+
+    /// <summary>
+    /// Function callable by the AI model (when enabled) to perform an ad-hoc chat history search.
+    /// </summary>
+    /// <param name="userQuestion">The query text.</param>
+    /// <param name="cancellationToken">Cancellation token.</param>
+    /// <returns>Formatted search results (may be empty).</returns>
+    internal async Task<string> SearchTextAsync(string userQuestion, CancellationToken cancellationToken = default)
+    {
+        if (string.IsNullOrWhiteSpace(userQuestion))
+        {
+            return string.Empty;
+        }
+
+        var results = await this.SearchChatHistoryAsync(userQuestion, this._maxResults, cancellationToken).ConfigureAwait(false);
+        if (!results.Any())
+        {
+            return string.Empty;
+        }
+
+        // Format the results as a single context message
+        var outputResultsText = string.Join("\n", results.Select(x => (string?)x["Content"]).Where(c => !string.IsNullOrWhiteSpace(c)));
+        if (string.IsNullOrWhiteSpace(outputResultsText))
+        {
+            return string.Empty;
+        }
+
+        var formatted = $"{this._contextPrompt}\n{outputResultsText}";
+
+        this._logger?.LogTrace(
+            "ChatHistoryMemoryProvider: Search Results\nInput:{Input}\nOutput:{MessageText}\n ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
+            userQuestion,
+            formatted,
+            this._searchScope.ApplicationId,
+            this._searchScope.AgentId,
+            this._searchScope.ThreadId,
+            this._searchScope.UserId);
+        return formatted;
+    }
+
+    /// <summary>
+    /// Searches for relevant chat history items based on the provided query text.
+    /// </summary>
+    /// <param name="queryText">The text to search for.</param>
+    /// <param name="top">The maximum number of results to return.</param>
+    /// <param name="cancellationToken">The cancellation token.</param>
+    /// <returns>A list of relevant chat history items.</returns>
+    private async Task<IEnumerable<Dictionary<string, object?>>> SearchChatHistoryAsync(
+        string queryText,
+        int top,
+        CancellationToken cancellationToken = default)
+    {
+        if (string.IsNullOrWhiteSpace(queryText))
+        {
+            return [];
+        }
+
+        var collection = await this.EnsureCollectionExistsAsync(cancellationToken).ConfigureAwait(false);
+
+        string? applicationId = this._searchScope.ApplicationId;
+        string? agentId = this._searchScope.AgentId;
+        string? userId = this._searchScope.UserId;
+        string? threadId = this._searchScope.ThreadId;
+
+        Expression<Func<Dictionary<string, object?>, bool>>? filter = null;
+        if (applicationId != null)
+        {
+            filter = x => (string?)x["ApplicationId"] == applicationId;
+        }
+
+        if (agentId != null)
+        {
+            Expression<Func<Dictionary<string, object?>, bool>> agentIdFilter = x => (string?)x["AgentId"] == agentId;
+            filter = filter == null ? agentIdFilter : Expression.Lambda<Func<Dictionary<string, object?>, bool>>(
+                Expression.AndAlso(filter.Body, agentIdFilter.Body),
+                filter.Parameters);
+        }
+
+        if (userId != null)
+        {
+            Expression<Func<Dictionary<string, object?>, bool>> userIdFilter = x => (string?)x["UserId"] == userId;
+            filter = filter == null ? userIdFilter : Expression.Lambda<Func<Dictionary<string, object?>, bool>>(
+                Expression.AndAlso(filter.Body, userIdFilter.Body),
+                filter.Parameters);
+        }
+
+        if (threadId != null)
+        {
+            Expression<Func<Dictionary<string, object?>, bool>> threadIdFilter = x => (string?)x["ThreadId"] == threadId;
+            filter = filter == null ? threadIdFilter : Expression.Lambda<Func<Dictionary<string, object?>, bool>>(
+                Expression.AndAlso(filter.Body, threadIdFilter.Body),
+                filter.Parameters);
+        }
+
+        // Use search to find relevant messages
+        var searchResults = collection.SearchAsync(
+            queryText,
+            top,
+            options: new()
+            {
+                Filter = filter
+            },
+            cancellationToken: cancellationToken);
+
+        var results = new List<Dictionary<string, object?>>();
+        await foreach (var result in searchResults.WithCancellation(cancellationToken).ConfigureAwait(false))
+        {
+            results.Add(result.Record);
+        }
+
+        this._logger?.LogInformation(
+            "ChatHistoryMemoryProvider: Retrieved {Count} search results. ApplicationId: '{ApplicationId}', AgentId: '{AgentId}', ThreadId: '{ThreadId}', UserId: '{UserId}'.",
+            results.Count,
+            this._searchScope.ApplicationId,
+            this._searchScope.AgentId,
+            this._searchScope.ThreadId,
+            this._searchScope.UserId);
+
+        return results;
+    }
+
+    /// <summary>
+    /// Ensures the collection exists in the vector store, creating it if necessary.
+    /// </summary>
+    /// <param name="cancellationToken">The cancellation token.</param>
+    /// <returns>The vector store collection.</returns>
+    private async Task<VectorStoreCollection<object, Dictionary<string, object?>>> EnsureCollectionExistsAsync(
+        CancellationToken cancellationToken = default)
+    {
+        if (this._collectionInitialized)
+        {
+            return this._collection;
+        }
+
+        await this._initializationLock.WaitAsync(cancellationToken).ConfigureAwait(false);
+        try
+        {
+            if (this._collectionInitialized)
+            {
+                return this._collection;
+            }
+
+            await this._collection.EnsureCollectionExistsAsync(cancellationToken).ConfigureAwait(false);
+            this._collectionInitialized = true;
+
+            return this._collection;
+        }
+        finally
+        {
+            this._initializationLock.Release();
+        }
+    }
+
+    /// <inheritdoc/>
+    private void Dispose(bool disposing)
+    {
+        if (!this._disposedValue)
+        {
+            if (disposing)
+            {
+                this._initializationLock.Dispose();
+                this._collection?.Dispose();
+            }
+
+            this._disposedValue = true;
+        }
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
+        this.Dispose(disposing: true);
+        GC.SuppressFinalize(this);
+    }
+
+    /// <summary>
+    /// Serializes the current provider state to a <see cref="JsonElement"/> including storage and search scopes.
+    /// </summary>
+    /// <param name="jsonSerializerOptions">Optional serializer options.</param>
+    /// <returns>Serialized provider state.</returns>
+    public override JsonElement Serialize(JsonSerializerOptions? jsonSerializerOptions = null)
+    {
+        var state = new ChatHistoryMemoryProviderState
+        {
+            StorageScope = this._storageScope,
+            SearchScope = this._searchScope,
+        };
+
+        var jso = jsonSerializerOptions ?? AgentJsonUtilities.DefaultOptions;
+        return JsonSerializer.SerializeToElement(state, jso.GetTypeInfo(typeof(ChatHistoryMemoryProviderState)));
+    }
+
+    private static ChatHistoryMemoryProviderState? DeserializeState(JsonElement serializedState, JsonSerializerOptions? jsonSerializerOptions)
+    {
+        if (serializedState.ValueKind != JsonValueKind.Object)
+        {
+            return null;
+        }
+
+        var jso = jsonSerializerOptions ?? AgentJsonUtilities.DefaultOptions;
+        return serializedState.Deserialize(jso.GetTypeInfo(typeof(ChatHistoryMemoryProviderState))) as ChatHistoryMemoryProviderState;
+    }
+
+    internal sealed class ChatHistoryMemoryProviderState
+    {
+        public ChatHistoryMemoryProviderScope? StorageScope { get; set; }
+        public ChatHistoryMemoryProviderScope? SearchScope { get; set; }
+    }
+}
@@ -0,0 +1,56 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Options controlling the behavior of <see cref="ChatHistoryMemoryProvider"/>.
+/// </summary>
+public sealed class ChatHistoryMemoryProviderOptions
+{
+    /// <summary>
+    /// Gets or sets a value indicating when the search should be executed.
+    /// </summary>
+    /// <value><see cref="SearchBehavior.BeforeAIInvoke"/> by default.</value>
+    public SearchBehavior SearchTime { get; set; } = SearchBehavior.BeforeAIInvoke;
+
+    /// <summary>
+    /// Gets or sets the name of the exposed search tool when operating in on-demand mode.
+    /// </summary>
+    /// <value>Defaults to "Search".</value>
+    public string? FunctionToolName { get; set; }
+
+    /// <summary>
+    /// Gets or sets the description of the exposed search tool when operating in on-demand mode.
+    /// </summary>
+    /// <value>Defaults to "Allows searching through previous chat history to help answer the user question.".</value>
+    public string? FunctionToolDescription { get; set; }
+
+    /// <summary>
+    /// Gets or sets the context prompt prefixed to results.
+    /// </summary>
+    public string? ContextPrompt { get; set; }
+
+    /// <summary>
+    /// Gets or sets the maximum number of results to retrieve from the chat history.
+    /// </summary>
+    /// <value>
+    /// Defaults to 3 if not set.
+    /// </value>
+    public int? MaxResults { get; set; }
+
+    /// <summary>
+    /// Behavior choices for the provider.
+    /// </summary>
+    public enum SearchBehavior
+    {
+        /// <summary>
+        /// Execute search prior to each invocation and inject results as a message.
+        /// </summary>
+        BeforeAIInvoke,
+
+        /// <summary>
+        /// Expose a function tool to perform search on-demand via function/tool calling.
+        /// </summary>
+        OnDemandFunctionCalling
+    }
+}
@@ -0,0 +1,53 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using Microsoft.Shared.Diagnostics;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// Allows scoping of chat history for the <see cref="ChatHistoryMemoryProvider"/>.
+/// </summary>
+public sealed class ChatHistoryMemoryProviderScope
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ChatHistoryMemoryProviderScope"/> class.
+    /// </summary>
+    public ChatHistoryMemoryProviderScope() { }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="ChatHistoryMemoryProviderScope"/> class by cloning an existing scope.
+    /// </summary>
+    /// <param name="sourceScope">The scope to clone.</param>
+    public ChatHistoryMemoryProviderScope(ChatHistoryMemoryProviderScope sourceScope)
+    {
+        Throw.IfNull(sourceScope);
+
+        this.ApplicationId = sourceScope.ApplicationId;
+        this.AgentId = sourceScope.AgentId;
+        this.ThreadId = sourceScope.ThreadId;
+        this.UserId = sourceScope.UserId;
+    }
+
+    /// <summary>
+    /// Gets or sets an optional ID for the application to scope chat history to.
+    /// </summary>
+    /// <remarks>If not set, the scope of the chat history will span all applications.</remarks>
+    public string? ApplicationId { get; set; }
+
+    /// <summary>
+    /// Gets or sets an optional ID for the agent to scope chat history to.
+    /// </summary>
+    /// <remarks>If not set, the scope of the chat history will span all agents.</remarks>
+    public string? AgentId { get; set; }
+
+    /// <summary>
+    /// Gets or sets an optional ID for the thread to scope chat history to.
+    /// </summary>
+    public string? ThreadId { get; set; }
+
+    /// <summary>
+    /// Gets or sets an optional ID for the user to scope chat history to.
+    /// </summary>
+    /// <remarks>If not set, the scope of the chat history will span all users.</remarks>
+    public string? UserId { get; set; }
+}
@@ -31,8 +31,10 @@
  </PropertyGroup>

  <ItemGroup>
-    <InternalsVisibleTo Include="Microsoft.Agents.AI.UnitTests" />
    <InternalsVisibleTo Include="DynamicProxyGenAssembly2" />
+
+    <InternalsVisibleTo Include="Microsoft.Agents.AI.UnitTests" />
+    <InternalsVisibleTo Include="Microsoft.Agents.AI.Hosting.UnitTests"/>
  </ItemGroup>

 </Project>