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Lab BMA2 - Build your first agent using M365 Agents SDK

In Lab BMA1 you built an agent that lives in Microsoft Foundry. Now you'll build the other half: the host that delivers it to users.

The Microsoft 365 Agents SDK gives you a production-shaped host — activity routing, conversation state, streaming, and channel delivery to Microsoft Teams and Microsoft 365 Copilot. You'll start from the simplest possible agent so the plumbing is obvious, then add the AI in Lab BMA3.

Lab objectives

By the end of this lab you will be able to:

  • Scaffold a Microsoft 365 Agents SDK project in Visual Studio
  • Explain how activities, handlers, and conversation state fit together
  • Run and test an agent locally in the Microsoft 365 Agents Playground

Exercise 1: Scaffold and explore the project

Step 1: Create the project

  1. Open Visual Studio 2022 and select Create a new project.
  2. Search for and select the Microsoft 365 Agents template.
  3. Name the project ContosoHRAgent and select Create.
  4. From the list of templates, select Echo Bot, then select Create.

An Echo Bot simply repeats back whatever the user sends. That's deliberate — it lets you verify the host, the local runtime, and the debugging loop before any model is involved.

Step 2: Explore what was generated

In Solution Explorer, expand the ContosoHRAgent project and open these two files:

File What it does
Program.cs Configures and runs the web host. Registers authentication, routing, storage, and the agent itself, and maps the /api/messages endpoint that every channel posts to.
Bot/EchoBot.cs The agent. It greets users when they join the conversation and handles every incoming message activity.

Look specifically at the constructor in EchoBot.cs:

  • OnConversationUpdate(ConversationUpdateEvents.MembersAdded, ...) runs when someone joins the conversation.
  • OnActivity(ActivityTypes.Message, ...) runs for every user message.

These two handlers are the extension points you'll replace in Lab BMA3.

Exercise 2: Run and test locally

Step 1: Start a debugging session

Select Start or press F5. The Microsoft 365 Agents Playground launches on localhost automatically.

If Visual Studio asks you to trust a self-issued SSL certificate for local development, accept it and continue.

Step 2: Verify the agent responds

Wait for the agent's "Hello and Welcome!" greeting, then send a few messages such as Hi or Hello.

Expected result:

  • The agent echoes your message back, prefixed with a running message count.
  • The right-hand panel shows the raw activity history for each turn.

The message counter proves conversation state is working — the same mechanism you'll use in Lab BMA3 to remember which Foundry conversation belongs to which chat.

Stop the debugging session before moving on.

Reference solution

A completed version of this lab is available at src/agents-sdk/BMA2-complete if you want to compare against your own project.

CONGRATULATIONS!

You have completed Lab BMA2 - Build your first agent using M365 Agents SDK!

You now have a working host and a working Foundry agent. Next, you'll connect them with Microsoft Agent Framework.