.NET: Simplify A2A client-server sample

dotnet/samples/05-end-to-end/A2AClientServer/A2AClient/A2AClient.csproj

@@ -10,14 +10,11 @@
 
   <ItemGroup>
     <PackageReference Include="A2A" />
-    <PackageReference Include="System.CommandLine" />
-    <PackageReference Include="Microsoft.Extensions.Hosting" />
   </ItemGroup>
 
   <ItemGroup>
     <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.A2A\Microsoft.Agents.AI.A2A.csproj" />
     <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.Abstractions\Microsoft.Agents.AI.Abstractions.csproj" />
-    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.OpenAI\Microsoft.Agents.AI.OpenAI.csproj" />
   </ItemGroup>
 
 </Project>

dotnet/samples/05-end-to-end/A2AClientServer/A2AClient/Program.cs

@@ -1,77 +1,41 @@
 // Copyright (c) Microsoft. All rights reserved.
 
-using System.CommandLine;
-using System.Reflection;
+// This sample shows how to discover and invoke an agent hosted by an A2A server.
+
+using A2A;
 using Microsoft.Agents.AI;
-using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.Logging;
 
-namespace A2A;
+// Initialize an A2ACardResolver to discover the policy agent.
+var agentUrl = Environment.GetEnvironmentVariable("A2A_AGENT_URL") ?? "http://localhost:5000/";
+var agentCardResolver = new A2ACardResolver(new Uri(agentUrl));
+
+// Create an AIAgent from the A2A agent card.
+AIAgent policyAgent = await agentCardResolver.GetAIAgentAsync();
+
+// Create a session so requests share the same A2A protocol context.
+AgentSession session = await policyAgent.CreateSessionAsync();
 
-public static class Program
+while (true)
 {
-    public static async Task<int> Main(string[] args)
-    {
-        // Create root command with options
-        var rootCommand = new RootCommand("A2AClient");
-        rootCommand.SetAction((_, ct) => HandleCommandsAsync(ct));
+    // Read the next request from the console.
+    Console.Write("\nUser (:q or quit to exit): ");
+    string? message = Console.ReadLine();
 
-        // Run the command
-        return await rootCommand.Parse(args).InvokeAsync();
+    if (string.IsNullOrWhiteSpace(message))
+    {
+        Console.WriteLine("Request cannot be empty.");
+        continue;
     }
 
-    private static async Task HandleCommandsAsync(CancellationToken cancellationToken)
+    if (message is ":q" or "quit")
     {
-        // Set up the logging
-        using var loggerFactory = LoggerFactory.Create(builder =>
-        {
-            builder.AddConsole();
-            builder.SetMinimumLevel(LogLevel.Information);
-        });
-        var logger = loggerFactory.CreateLogger("A2AClient");
-
-        // Retrieve configuration settings
-        IConfigurationRoot configRoot = new ConfigurationBuilder()
-            .AddEnvironmentVariables()
-            .AddUserSecrets(Assembly.GetExecutingAssembly())
-            .Build();
-        var apiKey = configRoot["A2AClient:ApiKey"] ?? throw new ArgumentException("A2AClient:ApiKey must be provided");
-        var modelId = configRoot["A2AClient:ModelId"] ?? "gpt-5.4-mini";
-        var agentUrls = configRoot["A2AClient:AgentUrls"] ?? "http://localhost:5000/;http://localhost:5001/;http://localhost:5002/";
-
-        // Create the Host agent
-        var hostAgent = new HostClientAgent(loggerFactory);
-        await hostAgent.InitializeAgentAsync(modelId, apiKey, agentUrls!.Split(";"));
-        AgentSession session = await hostAgent.Agent!.CreateSessionAsync(cancellationToken);
-        try
-        {
-            while (true)
-            {
-                // Get user message
-                Console.Write("\nUser (:q or quit to exit): ");
-                string? message = Console.ReadLine();
-                if (string.IsNullOrWhiteSpace(message))
-                {
-                    Console.WriteLine("Request cannot be empty.");
-                    continue;
-                }
-
-                if (message is ":q" or "quit")
-                {
-                    break;
-                }
+        break;
+    }
 
-                var agentResponse = await hostAgent.Agent!.RunAsync(message, session, cancellationToken: cancellationToken);
+    // Invoke the remote policy agent over A2A and display its response.
+    AgentResponse response = await policyAgent.RunAsync(message, session);
 
-                Console.ForegroundColor = ConsoleColor.Cyan;
-                Console.WriteLine($"\nAgent: {agentResponse.Text}");
-                Console.ResetColor();
-            }
-        }
-        catch (Exception ex)
-        {
-            logger.LogError(ex, "An error occurred while running the A2AClient");
-            return;
-        }
-    }
+    Console.ForegroundColor = ConsoleColor.Cyan;
+    Console.WriteLine($"\nPolicy agent: {response.Text}");
+    Console.ResetColor();
 }

dotnet/samples/05-end-to-end/A2AClientServer/A2AClient/README.md

@@ -1,26 +1,58 @@
-
-# A2A Client Sample
-Show how to create an A2A Client with a command line interface which invokes agents using the A2A protocol.
+# A2A client
 
-## Run the Sample
+This console client discovers and invokes the policy agent using the A2A protocol.
 
-To run the sample, follow these steps:
+## Run the sample
 
-1. Run the A2A client:
-    ```bash
-    cd A2AClient
-    dotnet run
-    ```  
-2. Enter your request e.g. "Show me all invoices for Contoso?"
+Start the server in a separate terminal:
 
-## Set Environment Variables
+```powershell
+az login
+$env:FOUNDRY_PROJECT_ENDPOINT="<your-project-endpoint>"
+$env:FOUNDRY_MODEL="gpt-5.4-mini"
+cd dotnet\samples\05-end-to-end\A2AClientServer\A2AServer
+dotnet run
+```
+
+Keep the server running, then start the client:
+
+```powershell
+cd dotnet\samples\05-end-to-end\A2AClientServer\A2AClient
+dotnet run
+```
 
-The agent urls are provided as a ` ` delimited list of strings
+Ask a question such as `What is the policy for short shipments?`.
+
+The client connects to `http://localhost:5000/` by default. To use another
+endpoint, restart the server with its listening and advertised URLs set:
 
 ```powershell
-cd dotnet/samples/05-end-to-end/A2AClientServer/A2AClient
+$env:ASPNETCORE_URLS="http://localhost:6000"
+$env:A2A_AGENT_URL="http://localhost:6000/"
+dotnet run
+```
 
-$env:OPENAI_CHAT_MODEL_NAME="gpt-5.4-mini"
-$env:OPENAI_API_KEY="<Your OPENAI api key>"
-$env:AGENT_URLS="http://localhost:5000/policy;http://localhost:5000/invoice;http://localhost:5000/logistics"
+Then set the discovery URL before starting the client:
+
+```powershell
+$env:A2A_AGENT_URL="http://localhost:6000/"
+dotnet run
 ```
+
+## Test the server with the HTTP file
+
+With the server running, open `..\A2AServer\A2AServer.http` in an editor that
+supports HTTP files, such as Visual Studio or Visual Studio Code with an HTTP
+client extension. Run the first request to retrieve the agent card, or the
+second request to invoke the policy agent directly.
+
+The file targets `http://localhost:5000` by default. Update its `@host` variable
+if the server listens at another address.
+
+## Inspect the server with A2A Inspector
+
+Follow the [A2A Inspector setup instructions](https://github.com/a2aproject/a2a-inspector)
+and connect it to the running server at `http://localhost:5000`.
+
+The Inspector provides another A2A client for viewing the agent card and sending
+messages without running this console client.

dotnet/samples/05-end-to-end/A2AClientServer/A2AServer/A2AServer.csproj

@@ -9,7 +9,6 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Azure.AI.Projects" />
     <PackageReference Include="Azure.Identity" />
   </ItemGroup>
 
@@ -24,7 +23,6 @@
 
     <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.A2A\Microsoft.Agents.AI.A2A.csproj" />
     <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.Foundry\Microsoft.Agents.AI.Foundry.csproj" />
-    <ProjectReference Include="..\..\..\..\src\Microsoft.Agents.AI.OpenAI\Microsoft.Agents.AI.OpenAI.csproj" />
   </ItemGroup>
 
 </Project>

dotnet/samples/05-end-to-end/A2AClientServer/A2AServer/A2AServer.http

@@ -1,85 +1,25 @@
-### Each A2A agent is available at a different host address
-@hostInvoice = http://localhost:5000
-@hostPolicy = http://localhost:5001
-@hostLogistics = http://localhost:5002
+@host = http://localhost:5000
 
-### Query agent card for the invoice agent
-GET {{hostInvoice}}/.well-known/agent-card.json
-
-### Send a message to the invoice agent
-POST {{hostInvoice}}
-Content-Type: application/json
-
-{
-    "id": "1",
-    "jsonrpc": "2.0",
-    "method": "message/send",
-    "params": {
-        "id": "12345",
-        "message": {
-            "kind": "message",
-            "role": "user",
-            "messageId": "msg_1",
-            "parts": [
-                {
-                    "kind": "text",
-                    "text": "Show me all invoices for Contoso?"
-                }
-            ]
-        }
-    }
-}
-
-### Query agent card for the policy agent
-GET {{hostPolicy}}/.well-known/agent-card.json
+### Query the policy agent card
+GET {{host}}/.well-known/agent-card.json
 
 ### Send a message to the policy agent
-POST {{hostPolicy}}
+POST {{host}}
 Content-Type: application/json
 
 {
     "id": "1",
     "jsonrpc": "2.0",
-    "method": "message/send",
+    "method": "SendMessage",
     "params": {
-        "id": "12345",
         "message": {
-            "kind": "message",
-            "role": "user",
+            "role": "ROLE_USER",
             "messageId": "msg_1",
             "parts": [
                 {
-                    "kind": "text",
                     "text": "What is the policy for short shipments?"
                 }
             ]
         }
     }
 }
-
-### Query agent card for the logistics agent
-GET {{hostLogistics}}/.well-known/agent-card.json
-
-### Send a message to the logistics agent
-POST {{hostLogistics}}
-Content-Type: application/json
-
-{
-    "id": "1",
-    "jsonrpc": "2.0",
-    "method": "message/send",
-    "params": {
-        "id": "12345",
-        "message": {
-            "kind": "message",
-            "role": "user",
-            "messageId": "msg_1",
-            "parts": [
-                {
-                    "kind": "text",
-                    "text": "What is the status for SHPMT-SAP-001?"
-                }
-            ]
-        }
-    }
-}