chore: import upstream snapshot with attribution

dotnet/samples/04-hosting/FoundryHostedAgents/invocations/Using-Samples/SimpleInvocationsAgent/InvocationsAIAgent.cs

@@ -0,0 +1,129 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Runtime.CompilerServices;
+using System.Text.Json;
+using Microsoft.Extensions.AI;
+
+namespace Microsoft.Agents.AI;
+
+/// <summary>
+/// An <see cref="AIAgent"/> that invokes a remote agent hosted with the Invocations protocol
+/// by sending plain-text HTTP POST requests to the <c>/invocations</c> endpoint.
+/// </summary>
+public sealed class InvocationsAIAgent : AIAgent
+{
+    private readonly HttpClient _httpClient;
+    private readonly Uri _invocationsUri;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="InvocationsAIAgent"/> class.
+    /// </summary>
+    /// <param name="agentEndpoint">
+    /// The base URI of the hosted agent (e.g., <c>http://localhost:8089</c>).
+    /// The <c>/invocations</c> path is appended automatically.
+    /// </param>
+    /// <param name="httpClient">Optional <see cref="HttpClient"/> to use. If <see langword="null"/>, a new instance is created.</param>
+    /// <param name="name">Optional name for the agent.</param>
+    /// <param name="description">Optional description for the agent.</param>
+    public InvocationsAIAgent(
+        Uri agentEndpoint,
+        HttpClient? httpClient = null,
+        string? name = null,
+        string? description = null)
+    {
+        ArgumentNullException.ThrowIfNull(agentEndpoint);
+
+        this._httpClient = httpClient ?? new HttpClient();
+
+        // Ensure the base URI ends with a slash so that combining works correctly.
+        var baseUri = agentEndpoint.AbsoluteUri.EndsWith('/')
+            ? agentEndpoint
+            : new Uri(agentEndpoint.AbsoluteUri + "/");
+        this._invocationsUri = new Uri(baseUri, "invocations");
+
+        this.Name = name ?? "invocations-agent";
+        this.Description = description ?? "An agent that calls a remote Invocations protocol endpoint.";
+    }
+
+    /// <inheritdoc/>
+    public override string? Name { get; }
+
+    /// <inheritdoc/>
+    public override string? Description { get; }
+
+    /// <inheritdoc/>
+    protected override async Task<AgentResponse> RunCoreAsync(
+        IEnumerable<ChatMessage> messages,
+        AgentSession? session = null,
+        AgentRunOptions? options = null,
+        CancellationToken cancellationToken = default)
+    {
+        var inputText = GetLastUserText(messages);
+        var responseText = await this.SendInvocationAsync(inputText, cancellationToken).ConfigureAwait(false);
+        return new AgentResponse(new ChatMessage(ChatRole.Assistant, responseText));
+    }
+
+    /// <inheritdoc/>
+    protected override async IAsyncEnumerable<AgentResponseUpdate> RunCoreStreamingAsync(
+        IEnumerable<ChatMessage> messages,
+        AgentSession? session = null,
+        AgentRunOptions? options = null,
+        [EnumeratorCancellation] CancellationToken cancellationToken = default)
+    {
+        // The Invocations protocol returns a complete response (no SSE streaming),
+        // so we yield a single update with the full text.
+        var inputText = GetLastUserText(messages);
+        var responseText = await this.SendInvocationAsync(inputText, cancellationToken).ConfigureAwait(false);
+
+        yield return new AgentResponseUpdate
+        {
+            Role = ChatRole.Assistant,
+            Contents = [new TextContent(responseText)],
+        };
+    }
+
+    /// <inheritdoc/>
+    protected override ValueTask<AgentSession> CreateSessionCoreAsync(CancellationToken cancellationToken = default)
+        => new(new InvocationsAgentSession());
+
+    /// <inheritdoc/>
+    protected override ValueTask<JsonElement> SerializeSessionCoreAsync(
+        AgentSession session,
+        JsonSerializerOptions? jsonSerializerOptions = null,
+        CancellationToken cancellationToken = default)
+        => new(JsonSerializer.SerializeToElement(new { }, jsonSerializerOptions));
+
+    /// <inheritdoc/>
+    protected override ValueTask<AgentSession> DeserializeSessionCoreAsync(
+        JsonElement serializedState,
+        JsonSerializerOptions? jsonSerializerOptions = null,
+        CancellationToken cancellationToken = default)
+        => new(new InvocationsAgentSession());
+
+    private async Task<string> SendInvocationAsync(string input, CancellationToken cancellationToken)
+    {
+        using var content = new StringContent(input, System.Text.Encoding.UTF8, "text/plain");
+        using var response = await this._httpClient.PostAsync(this._invocationsUri, content, cancellationToken).ConfigureAwait(false);
+        response.EnsureSuccessStatusCode();
+        return await response.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false);
+    }
+
+    private static string GetLastUserText(IEnumerable<ChatMessage> messages)
+    {
+        string? lastUserText = null;
+        foreach (var message in messages)
+        {
+            if (message.Role == ChatRole.User)
+            {
+                lastUserText = message.Text;
+            }
+        }
+
+        return lastUserText ?? string.Empty;
+    }
+
+    /// <summary>
+    /// Minimal session for the invocations agent. No state is persisted.
+    /// </summary>
+    private sealed class InvocationsAgentSession : AgentSession;
+}

dotnet/samples/04-hosting/FoundryHostedAgents/invocations/Using-Samples/SimpleInvocationsAgent/Program.cs

@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using DotNetEnv;
+using Microsoft.Agents.AI;
+
+// Load .env file if present (for local development)
+Env.TraversePath().Load();
+
+Uri agentEndpoint = new(Environment.GetEnvironmentVariable("AGENT_ENDPOINT")
+    ?? "http://localhost:8088");
+
+// Create an agent that calls the remote Invocations endpoint.
+InvocationsAIAgent agent = new(agentEndpoint);
+
+// REPL
+Console.ForegroundColor = ConsoleColor.Cyan;
+Console.WriteLine($"""
+    ══════════════════════════════════════════════════════════
+    Simple Invocations Agent Sample
+    Connected to: {agentEndpoint}
+    Type a message or 'quit' to exit
+    ══════════════════════════════════════════════════════════
+    """);
+Console.ResetColor();
+Console.WriteLine();
+
+while (true)
+{
+    Console.ForegroundColor = ConsoleColor.Green;
+    Console.Write("You> ");
+    Console.ResetColor();
+
+    string? input = Console.ReadLine();
+
+    if (string.IsNullOrWhiteSpace(input)) { continue; }
+    if (input.Equals("quit", StringComparison.OrdinalIgnoreCase)) { break; }
+
+    try
+    {
+        Console.ForegroundColor = ConsoleColor.Yellow;
+        Console.Write("Agent> ");
+        Console.ResetColor();
+
+        await foreach (var update in agent.RunStreamingAsync(input))
+        {
+            Console.Write(update);
+        }
+
+        Console.WriteLine();
+    }
+    catch (Exception ex)
+    {
+        Console.ForegroundColor = ConsoleColor.Red;
+        Console.WriteLine($"Error: {ex.Message}");
+        Console.ResetColor();
+    }
+
+    Console.WriteLine();
+}
+
+Console.WriteLine("Goodbye!");

dotnet/samples/04-hosting/FoundryHostedAgents/invocations/Using-Samples/SimpleInvocationsAgent/SimpleInvocationsAgent.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFrameworks>net10.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <CentralPackageTransitivePinningEnabled>false</CentralPackageTransitivePinningEnabled>
+    <RootNamespace>SimpleInvocationsAgentClient</RootNamespace>
+    <AssemblyName>simple-invocations-agent-client</AssemblyName>
+    <NoWarn>$(NoWarn);NU1605</NoWarn>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="DotNetEnv" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\..\..\src\Microsoft.Agents.AI.Abstractions\Microsoft.Agents.AI.Abstractions.csproj" />
+  </ItemGroup>
+
+</Project>