.NET: Add Anthropic Agent Package (#2359)

* WIP * WIP * Simple call working * Update Thinking sample * Non-Streaming Function calling working * Update Anthropic Impl * Public Preps * UT + IT working * Update documentation + samples * Update variable * Revert nuget.config * Add IT for BetaService implementation * Remove polyfill + enable IT to run for netstandard 2.0 * Skipping Anthropic IT's for manual execution and avoid pipeline execution * Fix compilation error * Address error in UT * Apply suggestions from code review Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> * Fix warning * Net 10 update * Update for NET 10, remove Anthropic.Foundry due to vulnerability * Final missing adjustments for NET 10 * Address PR comments * Remove unused code * Address feedback --------- Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
2026-06-16 21:04:09 +08:00 · 2025-11-25 11:53:18 +00:00
parent 112410ecd6
commit 1dde57981e
33 changed files with 1628 additions and 2 deletions
@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <InjectSharedIntegrationTestCode>True</InjectSharedIntegrationTestCode>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Configuration" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Json" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" />
+  </ItemGroup>
+  
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Microsoft.Agents.AI.Anthropic\Microsoft.Agents.AI.Anthropic.csproj" />
+    <ProjectReference Include="..\AgentConformance.IntegrationTests\AgentConformance.IntegrationTests.csproj" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,26 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Threading.Tasks;
+using AgentConformance.IntegrationTests;
+
+namespace AnthropicChatCompletion.IntegrationTests;
+
+public abstract class SkipAllChatClientRunStreaming(Func<AnthropicChatCompletionFixture> func) : ChatClientAgentRunStreamingTests<AnthropicChatCompletionFixture>(func)
+{
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithFunctionsInvokesFunctionsAndReturnsExpectedResultsAsync()
+        => base.RunWithFunctionsInvokesFunctionsAndReturnsExpectedResultsAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithInstructionsAndNoMessageReturnsExpectedResultAsync()
+        => base.RunWithInstructionsAndNoMessageReturnsExpectedResultAsync();
+}
+
+public class AnthropicBetaChatCompletionChatClientAgentReasoningRunStreamingTests() : SkipAllChatClientRunStreaming(() => new(useReasoningChatModel: true, useBeta: true));
+
+public class AnthropicBetaChatCompletionChatClientAgentRunStreamingTests() : SkipAllChatClientRunStreaming(() => new(useReasoningChatModel: false, useBeta: true));
+
+public class AnthropicChatCompletionChatClientAgentRunStreamingTests() : SkipAllChatClientRunStreaming(() => new(useReasoningChatModel: false, useBeta: false));
+
+public class AnthropicChatCompletionChatClientAgentReasoningRunStreamingTests() : SkipAllChatClientRunStreaming(() => new(useReasoningChatModel: true, useBeta: false));
@@ -0,0 +1,30 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Threading.Tasks;
+using AgentConformance.IntegrationTests;
+
+namespace AnthropicChatCompletion.IntegrationTests;
+
+public abstract class SkipAllChatClientAgentRun(Func<AnthropicChatCompletionFixture> func) : ChatClientAgentRunTests<AnthropicChatCompletionFixture>(func)
+{
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithFunctionsInvokesFunctionsAndReturnsExpectedResultsAsync()
+        => base.RunWithFunctionsInvokesFunctionsAndReturnsExpectedResultsAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithInstructionsAndNoMessageReturnsExpectedResultAsync()
+        => base.RunWithInstructionsAndNoMessageReturnsExpectedResultAsync();
+}
+
+public class AnthropicBetaChatCompletionChatClientAgentRunTests()
+    : SkipAllChatClientAgentRun(() => new(useReasoningChatModel: false, useBeta: true));
+
+public class AnthropicBetaChatCompletionChatClientAgentReasoningRunTests()
+    : SkipAllChatClientAgentRun(() => new(useReasoningChatModel: true, useBeta: true));
+
+public class AnthropicChatCompletionChatClientAgentRunTests()
+    : SkipAllChatClientAgentRun(() => new(useReasoningChatModel: false, useBeta: false));
+
+public class AnthropicChatCompletionChatClientAgentReasoningRunTests()
+    : SkipAllChatClientAgentRun(() => new(useReasoningChatModel: true, useBeta: false));
@@ -0,0 +1,105 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using AgentConformance.IntegrationTests;
+using AgentConformance.IntegrationTests.Support;
+using Anthropic;
+using Anthropic.Models.Beta.Messages;
+using Anthropic.Models.Messages;
+using Microsoft.Agents.AI;
+using Microsoft.Extensions.AI;
+using Shared.IntegrationTests;
+
+namespace AnthropicChatCompletion.IntegrationTests;
+
+public class AnthropicChatCompletionFixture : IChatClientAgentFixture
+{
+    // All tests for Anthropic are intended to be ran locally as the CI pipeline for Anthropic is not setup.
+    internal const string SkipReason = "Integrations tests for local execution only";
+
+    private static readonly AnthropicConfiguration s_config = TestConfiguration.LoadSection<AnthropicConfiguration>();
+    private readonly bool _useReasoningModel;
+    private readonly bool _useBeta;
+
+    private ChatClientAgent _agent = null!;
+
+    public AnthropicChatCompletionFixture(bool useReasoningChatModel, bool useBeta)
+    {
+        this._useReasoningModel = useReasoningChatModel;
+        this._useBeta = useBeta;
+    }
+
+    public AIAgent Agent => this._agent;
+
+    public IChatClient ChatClient => this._agent.ChatClient;
+
+    public async Task<List<ChatMessage>> GetChatHistoryAsync(AgentThread thread)
+    {
+        var typedThread = (ChatClientAgentThread)thread;
+
+        return typedThread.MessageStore is null ? [] : (await typedThread.MessageStore.GetMessagesAsync()).ToList();
+    }
+
+    public Task<ChatClientAgent> CreateChatClientAgentAsync(
+        string name = "HelpfulAssistant",
+        string instructions = "You are a helpful assistant.",
+        IList<AITool>? aiTools = null)
+    {
+        var anthropicClient = new AnthropicClient() { APIKey = s_config.ApiKey };
+
+        IChatClient? chatClient = this._useBeta
+            ? anthropicClient
+                .Beta
+                .AsIChatClient()
+                .AsBuilder()
+                .ConfigureOptions(options
+                     => options.RawRepresentationFactory = _
+                     => new Anthropic.Models.Beta.Messages.MessageCreateParams()
+                     {
+                         Model = options.ModelId ?? (this._useReasoningModel ? s_config.ChatReasoningModelId : s_config.ChatModelId),
+                         MaxTokens = options.MaxOutputTokens ?? 4096,
+                         Messages = [],
+                         Thinking = this._useReasoningModel
+                            ? new BetaThinkingConfigParam(new BetaThinkingConfigEnabled(2048))
+                            : new BetaThinkingConfigParam(new BetaThinkingConfigDisabled())
+                     }).Build()
+
+            : anthropicClient
+                .AsIChatClient()
+                .AsBuilder()
+                .ConfigureOptions(options
+                     => options.RawRepresentationFactory = _
+                     => new Anthropic.Models.Messages.MessageCreateParams()
+                     {
+                         Model = options.ModelId ?? (this._useReasoningModel ? s_config.ChatReasoningModelId : s_config.ChatModelId),
+                         MaxTokens = options.MaxOutputTokens ?? 4096,
+                         Messages = [],
+                         Thinking = this._useReasoningModel
+                            ? new ThinkingConfigParam(new ThinkingConfigEnabled(2048))
+                            : new ThinkingConfigParam(new ThinkingConfigDisabled())
+                     }).Build();
+
+        return Task.FromResult(new ChatClientAgent(chatClient, options: new()
+        {
+            Name = name,
+            Instructions = instructions,
+            ChatOptions = new() { Tools = aiTools }
+        }));
+    }
+
+    public Task DeleteAgentAsync(ChatClientAgent agent) =>
+        // Chat Completion does not require/support deleting agents, so this is a no-op.
+        Task.CompletedTask;
+
+    public Task DeleteThreadAsync(AgentThread thread) =>
+        // Chat Completion does not require/support deleting threads, so this is a no-op.
+        Task.CompletedTask;
+
+    public async Task InitializeAsync() =>
+        this._agent = await this.CreateChatClientAgentAsync();
+
+    public Task DisposeAsync() =>
+        Task.CompletedTask;
+}
@@ -0,0 +1,37 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Threading.Tasks;
+using AgentConformance.IntegrationTests;
+
+namespace AnthropicChatCompletion.IntegrationTests;
+
+public abstract class SkipAllRunStreaming(Func<AnthropicChatCompletionFixture> func) : RunStreamingTests<AnthropicChatCompletionFixture>(func)
+{
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithChatMessageReturnsExpectedResultAsync() => base.RunWithChatMessageReturnsExpectedResultAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithNoMessageDoesNotFailAsync() => base.RunWithNoMessageDoesNotFailAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithChatMessagesReturnsExpectedResultAsync() => base.RunWithChatMessagesReturnsExpectedResultAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithStringReturnsExpectedResultAsync() => base.RunWithStringReturnsExpectedResultAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task ThreadMaintainsHistoryAsync() => base.ThreadMaintainsHistoryAsync();
+}
+
+public class AnthropicBetaChatCompletionRunStreamingTests()
+    : SkipAllRunStreaming(() => new(useReasoningChatModel: false, useBeta: true));
+
+public class AnthropicBetaChatCompletionReasoningRunStreamingTests()
+    : SkipAllRunStreaming(() => new(useReasoningChatModel: true, useBeta: true));
+
+public class AnthropicChatCompletionRunStreamingTests()
+    : SkipAllRunStreaming(() => new(useReasoningChatModel: false, useBeta: false));
+
+public class AnthropicChatCompletionReasoningRunStreamingTests()
+    : SkipAllRunStreaming(() => new(useReasoningChatModel: true, useBeta: false));
@@ -0,0 +1,37 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Threading.Tasks;
+using AgentConformance.IntegrationTests;
+
+namespace AnthropicChatCompletion.IntegrationTests;
+
+public abstract class SkipAllRun(Func<AnthropicChatCompletionFixture> func) : RunTests<AnthropicChatCompletionFixture>(func)
+{
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithChatMessageReturnsExpectedResultAsync() => base.RunWithChatMessageReturnsExpectedResultAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithNoMessageDoesNotFailAsync() => base.RunWithNoMessageDoesNotFailAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithChatMessagesReturnsExpectedResultAsync() => base.RunWithChatMessagesReturnsExpectedResultAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task RunWithStringReturnsExpectedResultAsync() => base.RunWithStringReturnsExpectedResultAsync();
+
+    [Fact(Skip = AnthropicChatCompletionFixture.SkipReason)]
+    public override Task ThreadMaintainsHistoryAsync() => base.ThreadMaintainsHistoryAsync();
+}
+
+public class AnthropicBetaChatCompletionRunTests()
+    : SkipAllRun(() => new(useReasoningChatModel: false, useBeta: true));
+
+public class AnthropicBetaChatCompletionReasoningRunTests()
+    : SkipAllRun(() => new(useReasoningChatModel: true, useBeta: true));
+
+public class AnthropicChatCompletionRunTests()
+    : SkipAllRun(() => new(useReasoningChatModel: false, useBeta: false));
+
+public class AnthropicChatCompletionReasoningRunTests()
+    : SkipAllRun(() => new(useReasoningChatModel: true, useBeta: false));
@@ -0,0 +1,290 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+#pragma warning disable IDE0052 // Remove unread private members
+
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Anthropic;
+using Anthropic.Core;
+using Anthropic.Services;
+using Microsoft.Extensions.AI;
+using Moq;
+using IBetaMessageService = Anthropic.Services.Beta.IMessageService;
+using IMessageService = Anthropic.Services.IMessageService;
+
+namespace Microsoft.Agents.AI.Anthropic.UnitTests.Extensions;
+
+/// <summary>
+/// Unit tests for the AnthropicClientExtensions class.
+/// </summary>
+public sealed class AnthropicBetaServiceExtensionsTests
+{
+    /// <summary>
+    /// Verify that CreateAIAgent with clientFactory parameter correctly applies the factory.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithClientFactory_AppliesFactoryCorrectly()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+        var testChatClient = new TestChatClient(chatClient.Beta.AsIChatClient());
+
+        // Act
+        var agent = chatClient.Beta.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            name: "Test Agent",
+            description: "Test description",
+            clientFactory: (innerClient) => testChatClient);
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+        Assert.Equal("Test description", agent.Description);
+
+        // Verify that the custom chat client can be retrieved from the agent's service collection
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.NotNull(retrievedTestClient);
+        Assert.Same(testChatClient, retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with clientFactory using AsBuilder pattern works correctly.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithClientFactoryUsingAsBuilder_AppliesFactoryCorrectly()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+        TestChatClient? testChatClient = null;
+
+        // Act
+        var agent = chatClient.Beta.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            clientFactory: (innerClient) =>
+                innerClient.AsBuilder().Use((innerClient) => testChatClient = new TestChatClient(innerClient)).Build());
+
+        // Assert
+        Assert.NotNull(agent);
+
+        // Verify that the custom chat client can be retrieved from the agent's service collection
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.NotNull(retrievedTestClient);
+        Assert.Same(testChatClient, retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with options and clientFactory parameter correctly applies the factory.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithOptionsAndClientFactory_AppliesFactoryCorrectly()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+        var testChatClient = new TestChatClient(chatClient.Beta.AsIChatClient());
+        var options = new ChatClientAgentOptions
+        {
+            Name = "Test Agent",
+            Description = "Test description",
+            Instructions = "Test instructions"
+        };
+
+        // Act
+        var agent = chatClient.Beta.CreateAIAgent(
+            options,
+            clientFactory: (innerClient) => testChatClient);
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+        Assert.Equal("Test description", agent.Description);
+
+        // Verify that the custom chat client can be retrieved from the agent's service collection
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.NotNull(retrievedTestClient);
+        Assert.Same(testChatClient, retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent without clientFactory works normally.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithoutClientFactory_WorksNormally()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+
+        // Act
+        var agent = chatClient.Beta.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            name: "Test Agent");
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+
+        // Verify that no TestChatClient is available since no factory was provided
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.Null(retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with null clientFactory works normally.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithNullClientFactory_WorksNormally()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+
+        // Act
+        var agent = chatClient.Beta.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            name: "Test Agent",
+            clientFactory: null);
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+
+        // Verify that no TestChatClient is available since no factory was provided
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.Null(retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent throws ArgumentNullException when client is null.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithNullClient_ThrowsArgumentNullException()
+    {
+        // Act & Assert
+        var exception = Assert.Throws<ArgumentNullException>(() =>
+            ((IBetaService)null!).CreateAIAgent("test-model"));
+
+        Assert.Equal("betaService", exception.ParamName);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with options throws ArgumentNullException when options is null.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithNullOptions_ThrowsArgumentNullException()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+
+        // Act & Assert
+        var exception = Assert.Throws<ArgumentNullException>(() =>
+            chatClient.Beta.CreateAIAgent((ChatClientAgentOptions)null!));
+
+        Assert.Equal("options", exception.ParamName);
+    }
+
+    /// <summary>
+    /// Test custom chat client that can be used to verify clientFactory functionality.
+    /// </summary>
+    private sealed class TestChatClient : IChatClient
+    {
+        private readonly IChatClient _innerClient;
+
+        public TestChatClient(IChatClient innerClient)
+        {
+            this._innerClient = innerClient;
+        }
+
+        public Task<ChatResponse> GetResponseAsync(IEnumerable<ChatMessage> messages, ChatOptions? options = null, CancellationToken cancellationToken = default)
+            => this._innerClient.GetResponseAsync(messages, options, cancellationToken);
+
+        public async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseAsync(
+            IEnumerable<ChatMessage> messages, ChatOptions? options = null, [EnumeratorCancellation] CancellationToken cancellationToken = default)
+        {
+            await foreach (var update in this._innerClient.GetStreamingResponseAsync(messages, options, cancellationToken))
+            {
+                yield return update;
+            }
+        }
+
+        public object? GetService(Type serviceType, object? serviceKey = null)
+        {
+            // Return this instance when requested
+            if (serviceType == typeof(TestChatClient))
+            {
+                return this;
+            }
+
+            return this._innerClient.GetService(serviceType, serviceKey);
+        }
+
+        public void Dispose() => this._innerClient.Dispose();
+    }
+
+    /// <summary>
+    /// Creates a test ChatClient implementation for testing.
+    /// </summary>
+    private sealed class TestAnthropicChatClient : IAnthropicClient
+    {
+        public TestAnthropicChatClient()
+        {
+            this.BetaService = new TestBetaService(this);
+        }
+
+        public HttpClient HttpClient { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public Uri BaseUrl { get => new("http://localhost"); init => throw new NotImplementedException(); }
+        public bool ResponseValidation { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public int? MaxRetries { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public TimeSpan? Timeout { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public string? APIKey { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public string? AuthToken { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+
+        public IMessageService Messages => throw new NotImplementedException();
+
+        public IModelService Models => throw new NotImplementedException();
+
+        public IBetaService Beta => this.BetaService;
+
+        public IBetaService BetaService { get; }
+
+        IMessageService IAnthropicClient.Messages => new Mock<IMessageService>().Object;
+
+        public Task<HttpResponse> Execute<T>(HttpRequest<T> request, CancellationToken cancellationToken = default) where T : ParamsBase
+        {
+            throw new NotImplementedException();
+        }
+
+        public IAnthropicClient WithOptions(Func<ClientOptions, ClientOptions> modifier)
+        {
+            throw new NotImplementedException();
+        }
+
+        private sealed class TestBetaService : IBetaService
+        {
+            private readonly IAnthropicClient _client;
+
+            public TestBetaService(IAnthropicClient client)
+            {
+                this._client = client;
+            }
+
+            public global::Anthropic.Services.Beta.IModelService Models => throw new NotImplementedException();
+
+            public global::Anthropic.Services.Beta.IFileService Files => throw new NotImplementedException();
+
+            public global::Anthropic.Services.Beta.ISkillService Skills => throw new NotImplementedException();
+
+            public IBetaMessageService Messages => new Mock<IBetaMessageService>().Object;
+
+            public IBetaService WithOptions(Func<ClientOptions, ClientOptions> modifier)
+            {
+                throw new NotImplementedException();
+            }
+        }
+    }
+}
@@ -0,0 +1,257 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Anthropic;
+using Anthropic.Core;
+using Anthropic.Services;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI.Anthropic.UnitTests.Extensions;
+
+/// <summary>
+/// Unit tests for the AnthropicClientExtensions class.
+/// </summary>
+public sealed class AnthropicClientExtensionsTests
+{
+    /// <summary>
+    /// Test custom chat client that can be used to verify clientFactory functionality.
+    /// </summary>
+    private sealed class TestChatClient : IChatClient
+    {
+        private readonly IChatClient _innerClient;
+
+        public TestChatClient(IChatClient innerClient)
+        {
+            this._innerClient = innerClient;
+        }
+
+        public Task<ChatResponse> GetResponseAsync(IEnumerable<ChatMessage> messages, ChatOptions? options = null, CancellationToken cancellationToken = default)
+            => this._innerClient.GetResponseAsync(messages, options, cancellationToken);
+
+        public async IAsyncEnumerable<ChatResponseUpdate> GetStreamingResponseAsync(
+            IEnumerable<ChatMessage> messages, ChatOptions? options = null, [EnumeratorCancellation] CancellationToken cancellationToken = default)
+        {
+            await foreach (var update in this._innerClient.GetStreamingResponseAsync(messages, options, cancellationToken))
+            {
+                yield return update;
+            }
+        }
+
+        public object? GetService(Type serviceType, object? serviceKey = null)
+        {
+            // Return this instance when requested
+            if (serviceType == typeof(TestChatClient))
+            {
+                return this;
+            }
+
+            return this._innerClient.GetService(serviceType, serviceKey);
+        }
+
+        public void Dispose() => this._innerClient.Dispose();
+    }
+
+    /// <summary>
+    /// Creates a test ChatClient implementation for testing.
+    /// </summary>
+    private sealed class TestAnthropicChatClient : IAnthropicClient
+    {
+        public TestAnthropicChatClient()
+        {
+        }
+
+        public HttpClient HttpClient { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public Uri BaseUrl { get => new("http://localhost"); init => throw new NotImplementedException(); }
+        public bool ResponseValidation { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public int? MaxRetries { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public TimeSpan? Timeout { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public string? APIKey { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+        public string? AuthToken { get => throw new NotImplementedException(); init => throw new NotImplementedException(); }
+
+        public IMessageService Messages => throw new NotImplementedException();
+
+        public IModelService Models => throw new NotImplementedException();
+
+        public IBetaService Beta => throw new NotImplementedException();
+
+        public Task<HttpResponse> Execute<T>(HttpRequest<T> request, CancellationToken cancellationToken = default) where T : ParamsBase
+        {
+            throw new NotImplementedException();
+        }
+
+        public IAnthropicClient WithOptions(Func<ClientOptions, ClientOptions> modifier)
+        {
+            throw new NotImplementedException();
+        }
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with clientFactory parameter correctly applies the factory.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithClientFactory_AppliesFactoryCorrectly()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+        var testChatClient = new TestChatClient(chatClient.AsIChatClient());
+
+        // Act
+        var agent = chatClient.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            name: "Test Agent",
+            description: "Test description",
+            clientFactory: (innerClient) => testChatClient);
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+        Assert.Equal("Test description", agent.Description);
+
+        // Verify that the custom chat client can be retrieved from the agent's service collection
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.NotNull(retrievedTestClient);
+        Assert.Same(testChatClient, retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with clientFactory using AsBuilder pattern works correctly.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithClientFactoryUsingAsBuilder_AppliesFactoryCorrectly()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+        TestChatClient? testChatClient = null;
+
+        // Act
+        var agent = chatClient.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            clientFactory: (innerClient) =>
+                innerClient.AsBuilder().Use((innerClient) => testChatClient = new TestChatClient(innerClient)).Build());
+
+        // Assert
+        Assert.NotNull(agent);
+
+        // Verify that the custom chat client can be retrieved from the agent's service collection
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.NotNull(retrievedTestClient);
+        Assert.Same(testChatClient, retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with options and clientFactory parameter correctly applies the factory.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithOptionsAndClientFactory_AppliesFactoryCorrectly()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+        var testChatClient = new TestChatClient(chatClient.AsIChatClient());
+        var options = new ChatClientAgentOptions
+        {
+            Name = "Test Agent",
+            Description = "Test description",
+            Instructions = "Test instructions"
+        };
+
+        // Act
+        var agent = chatClient.CreateAIAgent(
+            options,
+            clientFactory: (innerClient) => testChatClient);
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+        Assert.Equal("Test description", agent.Description);
+
+        // Verify that the custom chat client can be retrieved from the agent's service collection
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.NotNull(retrievedTestClient);
+        Assert.Same(testChatClient, retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent without clientFactory works normally.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithoutClientFactory_WorksNormally()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+
+        // Act
+        var agent = chatClient.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            name: "Test Agent");
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+
+        // Verify that no TestChatClient is available since no factory was provided
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.Null(retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with null clientFactory works normally.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithNullClientFactory_WorksNormally()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+
+        // Act
+        var agent = chatClient.CreateAIAgent(
+            model: "test-model",
+            instructions: "Test instructions",
+            name: "Test Agent",
+            clientFactory: null);
+
+        // Assert
+        Assert.NotNull(agent);
+        Assert.Equal("Test Agent", agent.Name);
+
+        // Verify that no TestChatClient is available since no factory was provided
+        var retrievedTestClient = agent.GetService<TestChatClient>();
+        Assert.Null(retrievedTestClient);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent throws ArgumentNullException when client is null.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithNullClient_ThrowsArgumentNullException()
+    {
+        // Act & Assert
+        var exception = Assert.Throws<ArgumentNullException>(() =>
+            ((TestAnthropicChatClient)null!).CreateAIAgent("test-model"));
+
+        Assert.Equal("client", exception.ParamName);
+    }
+
+    /// <summary>
+    /// Verify that CreateAIAgent with options throws ArgumentNullException when options is null.
+    /// </summary>
+    [Fact]
+    public void CreateAIAgent_WithNullOptions_ThrowsArgumentNullException()
+    {
+        // Arrange
+        var chatClient = new TestAnthropicChatClient();
+
+        // Act & Assert
+        var exception = Assert.Throws<ArgumentNullException>(() =>
+            chatClient.CreateAIAgent((ChatClientAgentOptions)null!));
+
+        Assert.Equal("options", exception.ParamName);
+    }
+}
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <InjectIsExternalInitOnLegacy>true</InjectIsExternalInitOnLegacy>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Microsoft.Agents.AI.Anthropic\Microsoft.Agents.AI.Anthropic.csproj" />
+  </ItemGroup>
+
+</Project>