agent-framework/dotnet/samples/02-agents/AgentsWithFoundry/Agent_Step01_Basics

Creating and Running a Basic Agent with the Responses API

This sample demonstrates how to create and run a basic AI agent using the ChatClientAgent, which uses the Microsoft Foundry Responses API directly without creating server-side agent definitions.

What this sample demonstrates

• Creating a ChatClientAgent with instructions and a model
• Running a simple single-turn conversation
• No server-side agent creation or cleanup required

Prerequisites

Before you begin, ensure you have the following prerequisites:

• .NET 10 SDK or later
• Microsoft Foundry service endpoint and deployment configured
• An authenticated Azure identity (for example, sign in with az login)

Note: This sample uses DefaultAzureCredential. az login is the easiest local development path, but Visual Studio, VS Code, and managed identity credentials also work when available.

Set the following environment variables:

$env:FOUNDRY_PROJECT_ENDPOINT="https://your-foundry-service.services.ai.azure.com/api/projects/your-foundry-project"
$env:FOUNDRY_MODEL="gpt-5.4-mini"

Run the sample

Navigate to the AgentsWithFoundry sample directory and run:

cd dotnet/samples/02-agents/AgentsWithFoundry
dotnet run --project .\Agent_Step01_Basics

Alternative: Composable approach

You can also create the same agent by composing the underlying IChatClient directly. This gives you full control over the chat client pipeline:

using Azure.AI.Projects;
using Azure.Identity;
using Microsoft.Agents.AI;
using Microsoft.Extensions.AI;

AIProjectClient aiProjectClient = new(new Uri(endpoint), new DefaultAzureCredential());

AIAgent agent = new ChatClientAgent(
    chatClient: aiProjectClient.GetProjectOpenAIClient().GetProjectResponsesClient().AsIChatClient(deploymentName),
    instructions: "You are good at telling jokes.",
    name: "JokerAgent");

This approach is useful when you need to customize the chat client pipeline or swap providers (e.g., Anthropic, OpenAI) while keeping the same agent code.