Understand agent concepts

An agent's interactions can be using text, speech, images, or video. It processes the user's input to understand their request and evaluates the input to perform relevant tasks. An agent may request information or enable access to services, and responds to the user.

Agent scopes

Agents in Microsoft Teams can be part of a one-to-one conversation, a group chat, or a channel in a team. Each scope provides unique opportunities and challenges for your conversational agent.

In a channel	In a group chat	In a one-to-one chat
Massive reach	Fewer members	Traditional way
Concise individual interactions	@mention to agent	Q&A agents
@mention to agent	Similar to channel	Agents that tell jokes and take notes

In a channel

Channels contain threaded conversations between multiple people, even up to 2000. This potentially gives your agent massive reach, but individual interactions must be concise. Traditional multi-turn interactions don't work. Instead, you must look to use interactive cards or dialogs (referred as task modules in TeamsJS v1.x), or move the conversation to a one-to-one conversation to collect lots of information. Your agent only has access to messages where it's @mentioned. You can retrieve additional messages from the conversation using Microsoft Graph and organization-level permissions.

Agents work better in a channel in the following cases:

• Notifications, where you provide an interactive card for users to take additional information.
• Feedback scenarios, such as polls and surveys.
• Single request or response cycle resolves interactions and the results are useful for multiple members of the conversation.
• Social or fun agents, where you get an awesome cat image, randomly pick a winner, and so on.

In a group chat

Group chats are non-threaded conversations between three or more people. They tend to have fewer members than a channel and are more transient. Similar to a channel, your agent only has access to messages where it's @mentioned directly.

Agents that work better in a channel also work better in a group chat.

In a one-to-one chat

One-to-one chat is a traditional way for a conversational agent to interact with a user. A few examples of one-to-one conversational agents are:

• Q&A agents
• agents that initiate workflows in other systems.
• agents that tell jokes.
• agents that take notes. Before creating one-to-one agents, consider whether a conversation-based interface is the best way to present your functionality.

Activity handler and agent logic

To create an agent app that meets your needs, understanding Microsoft Teams activity handler and agent logic is essential. These two key components work together to organize conversational logic.

• Teams activity handler: Processes Teams-specific events and interactions such as channel creation, team member additions, and other actions unique to the Teams environment. In the Teams SDK v2, handlers are registered directly on an App instance rather than via class inheritance.

• Agent logic: The App object houses the agent's conversational logic and is responsible for making decisions based on user input. Incoming activities are routed to the appropriate handler based on activity type and optional pattern matching.

Teams activity handler

The activity handler is the core of an agent's functionality, managing and processing user interactions. In the Teams SDK v2:

• You instantiate an App object and register handlers on it.
• Handlers receive a typed context object (IActivityContext in TypeScript, IContext<TActivity> in C#, ActivityContext[TActivity] in Python).
• Replies and proactive messages are sent via ctx.reply() or ctx.send().

When a Teams agent receives an activity, the SDK routes it through the registered handler. Teams-specific events (channel lifecycle, member changes, etc.) are surfaced as distinct named events, so you do not need to inspect channelData.eventType manually.

Note

If an agent activity takes more than 15 seconds to process, Teams sends a retry request to the agent endpoint, so you might see duplicate requests.

Activity handler code snippets

The following snippets show Teams activity handlers for channel and team lifecycle events.

TypeScript

Agents are built using the @microsoft/teams.apps package. You instantiate an App and register handlers with app.on(eventName, handler). The SDK routes activities to the correct handler based on the event name string.

channelCreated

import { App } from '@microsoft/teams.apps';

const app = new App();

app.on('channelCreated', async ({ activity }) => {
  const channel = activity.channelData.channel; // { id, name }
  const team    = activity.channelData.team;    // { id, name }
  // Code logic here
});

channelDeleted

app.on('channelDeleted', async ({ activity }) => {
  // Code logic here
});

channelRenamed

app.on('channelRenamed', async ({ activity }) => {
  // Code logic here
});

teamRenamed

app.on('teamRenamed', async ({ activity }) => {
  // Code logic here
});

membersAdded / membersRemoved

app.on('membersAdded', async ({ activity, send }) => {
  for (const member of activity.membersAdded) {
    await send(`Welcome, ${member.name}!`);
  }
});

app.on('membersRemoved', async ({ activity }) => {
  // Code logic here
});

messageUpdate / messageDelete

Message edits are surfaced as messageUpdate. Soft deletes are surfaced as messageDelete — the activity.channelData.eventType will be 'softDeleteMessage'.

app.on('messageUpdate', async ({ activity }) => {
  // Code logic here
});

app.on('messageDelete', async ({ activity }) => {
  // activity.channelData.eventType === 'softDeleteMessage' for soft deletes
  // Code logic here
});

C#

Agents are built using the Microsoft.Teams.Apps package. You instantiate an App and chain handler registrations using extension methods such as OnMessage(), OnChannelCreated(), etc. All handlers receive an IContext<TActivity> object.

OnChannelCreated

using Microsoft.Teams.Apps;

var app = new App();

app.OnChannelCreated(async context => {
    var channel = context.Activity.ChannelData.Channel;
    var team    = context.Activity.ChannelData.Team;
    // Code logic here
});

OnChannelDeleted

app.OnChannelDeleted(async context => {
    // Code logic here
});

OnChannelRenamed

app.OnChannelRenamed(async context => {
    // Code logic here
});

OnTeamRenamed

app.OnTeamRenamed(async context => {
    // Code logic here
});

OnMembersAdded

app.OnMembersAdded(async context => {
    foreach (var member in context.Activity.MembersAdded) {
        // Code logic here
    }
});

OnMembersRemoved

app.OnMembersRemoved(async context => {
    foreach (var member in context.Activity.MembersRemoved) {
        // Code logic here
    }
});

OnMessageUpdate / OnMessageDelete

Message edits are handled via OnMessageUpdate. Soft deletes are handled via OnMessageDelete.

app.OnMessageUpdate(async context => {
    // Code logic here
});

app.OnMessageDelete(async context => {
    // Code logic here
});

Python

Agents are built using the microsoft-teams-apps package. Handlers are registered using decorators on an App instance. Each handler is an async function that receives an ActivityContext[TActivity] object.

on_channel_created

from microsoft_teams.apps import App, ActivityContext
from microsoft_teams.api.activities import ConversationUpdateActivity

app = App()

@app.on_channel_created
async def handle_channel_created(ctx: ActivityContext[ConversationUpdateActivity]):
    channel = ctx.activity.channel_data.channel
    team    = ctx.activity.channel_data.team
    # Code logic here

on_channel_deleted

@app.on_channel_deleted
async def handle_channel_deleted(ctx: ActivityContext[ConversationUpdateActivity]):
    # Code logic here

on_channel_renamed

@app.on_channel_renamed
async def handle_channel_renamed(ctx: ActivityContext[ConversationUpdateActivity]):
    # Code logic here

on_team_renamed

@app.on_team_renamed
async def handle_team_renamed(ctx: ActivityContext[ConversationUpdateActivity]):
    # Code logic here

on_conversation_update (members added / removed)

Members added and removed events are handled via on_conversation_update. Inspect ctx.activity.members_added and ctx.activity.members_removed:

@app.on_conversation_update
async def handle_conversation_update(ctx: ActivityContext[ConversationUpdateActivity]):
    if ctx.activity.members_added:
        for member in ctx.activity.members_added:
            await ctx.send(f"Welcome, {member.name}!")
    if ctx.activity.members_removed:
        # Code logic here

on_edit_message / on_soft_delete_message / on_undelete_message

@app.on_edit_message
async def handle_edit_message(ctx: ActivityContext):
    # Code logic here

@app.on_soft_delete_message
async def handle_soft_delete_message(ctx: ActivityContext):
    # Code logic here

@app.on_undelete_message
async def handle_undelete_message(ctx: ActivityContext):
    # Code logic here

Example of agent activity handler

The following code provides an example of an agent activity:

TypeScript

import { App } from '@microsoft/teams.apps';

const app = new App();

app.on('message', async ({ activity, reply }) => {
  const senderName = activity.from.name;
  await send(`Hello <at>${senderName}</at>.`);
});

app.start().catch(console.error);

C#

using Microsoft.Teams.Apps.Activities;
using Microsoft.Teams.Apps.Extensions;
using Microsoft.Teams.Plugins.AspNetCore.DevTools.Extensions;
using Microsoft.Teams.Plugins.AspNetCore.Extensions;

var builder = WebApplication.CreateBuilder(args);
builder.AddTeams().AddTeamsDevTools();
var app = builder.Build();
var teams = app.UseTeams();

teams.OnMessage(async (context, cancellationToken) =>
{
    var senderName = context.Activity.From.Name;
    await context.Send($"Hello <at>{senderName}</at>.", cancellationToken);
});

app.Run();

Python

import asyncio
from microsoft_teams.apps import App, ActivityContext
from microsoft_teams.api import MessageActivity

app = App()

@app.on_message
async def handle_message(ctx: ActivityContext[MessageActivity]):
    sender_name = ctx.activity.from_property.name
    await ctx.send(f"Hello <at>{sender_name}</at>.")

if __name__ == "__main__":
    asyncio.run(app.start())

Agent logic

Agent logic incorporates the fundamental rules and decision-making frameworks that dictate an agent's actions and interactions. It outlines how the agent interprets user input, formulates responses, and participates in conversations.

In Teams SDK v2, the agent logic processes incoming activities from one or more agent channels and generates outgoing activities. All activity routing is handled by the App instance — you register the handlers, and the SDK dispatches activities to them automatically.

TypeScript

Core activity handlers

The list of event names supported by app.on() includes the following:

Event	Event name string	Description
Any activity type received	'activity'	Catch-all handler called for every activity.
Message activity received	'message'	Handle incoming text messages. Use app.message(pattern, handler) for regex matching.
Conversation update received	'conversationUpdate'	Raw conversation update activity.
Installation added	'install.add'	Agent was installed.
Installation removed	'install.remove'	Agent was uninstalled.
Members added	'membersAdded'	One or more members joined the conversation.
Members removed	'membersRemoved'	One or more members left the conversation.
Message edited	'messageUpdate'	A message in the conversation was edited.
Message soft deleted	'messageDelete'	A message was soft-deleted (activity.channelData.eventType === 'softDeleteMessage').
Read receipt received	'readReceipt'	A read receipt was received.

Teams-specific event handlers

app.on() supports the following Teams-specific event name strings:

Event	Event name string	Description
channelCreated	'channelCreated'	A Teams channel was created.
channelDeleted	'channelDeleted'	A Teams channel was deleted.
channelRenamed	'channelRenamed'	A Teams channel was renamed.
channelRestored	'channelRestored'	A Teams channel was restored.
channelMemberAdded	'channelMemberAdded'	A member was added to a channel.
channelMemberRemoved	'channelMemberRemoved'	A member was removed from a channel.
teamRenamed	'teamRenamed'	The team was renamed.
teamArchived	'teamArchived'	The team was archived.
teamDeleted	'teamDeleted'	The team was deleted.
teamRestored	'teamRestored'	The team was restored.
Meeting started	'meetingStart'	A meeting has started.
Meeting ended	'meetingEnd'	A meeting has ended.
Participant joined	'meetingParticipantJoin'	A participant joined a meeting.
Participant left	'meetingParticipantLeave'	A participant left a meeting.

Teams invoke activities

The following table lists invoke activity handlers available via app.on():

Invoke type	Event name string	Description
CardAction.Invoke	'card.action'	A card action invoke activity was received (adaptiveCard/action).
signin/verifyState	Handled automatically by the SDK (OAuth flow)	Sign-in verify state activity.
task/fetch	'dialog.open'	A dialog (task module) was fetched.
task/submit	'dialog.submit'	A dialog (task module) was submitted.

C#

Core activity handlers

The App class exposes extension methods for registering handlers. Methods return App for fluent chaining.

Event	Extension method	Description
Any activity type received	OnActivity(handler)	Catch-all handler called for every activity.
Message activity received	OnMessage(handler)	Handle incoming text messages. Pass a regex string as the first argument for pattern matching.
Conversation update received	OnConversationUpdate(handler)	Raw conversation update activity.
Non-agent members joined	OnMembersAdded(handler)	Fires when MembersAdded.Length > 0.
Non-agent members left	OnMembersRemoved(handler)	Fires when MembersRemoved.Length > 0.
Installation added	OnInstall(handler)	Agent was installed.

Teams-specific activity handlers

Event	Extension method	Description
Channel created	OnChannelCreated(handler)	A Teams channel was created.
Channel deleted	OnChannelDeleted(handler)	A Teams channel was deleted.
Channel renamed	OnChannelRenamed(handler)	A Teams channel was renamed.
Team renamed	OnTeamRenamed(handler)	The team was renamed.
Message edited	OnMessageUpdate(handler)	A message was edited.
Message soft deleted	OnMessageDelete(handler)	A message was soft-deleted.

Teams invoke activities

Invoke type	Extension method	Description
CardAction.Invoke	OnExecuteAction(handler)	A card action invoke activity was received.
task/fetch	OnTaskFetch(handler)	A dialog (task module) was fetched.
task/submit	OnTaskSubmit(handler)	A dialog (task module) was submitted.
fileConsent/invoke	OnFileConsent(handler)	A file consent card activity was received.
signin/verifyState	Handled automatically by the SDK (OAuth flow)	Sign-in verify state activity.

Python

Core activity handlers

The App class exposes decorator-style handler registration.

Event	Decorator	Description
Any activity received	@app.on_activity	Catch-all handler for every activity.
Message received	@app.on_message	Handle incoming text messages.
Message with pattern	@app.on_message_pattern(re.compile(...))	Handle messages matching a regex pattern.
Conversation update	@app.on_conversation_update	Raw conversation update; check members_added / members_removed.
Installation added	@app.on_install_add	Agent was installed.
Installation removed	@app.on_install_remove	Agent was uninstalled.

Teams-specific activity handlers

Event	Decorator	Description
Channel created	@app.on_channel_created	A Teams channel was created.
Channel deleted	@app.on_channel_deleted	A Teams channel was deleted.
Channel renamed	@app.on_channel_renamed	A Teams channel was renamed.
Team renamed	@app.on_team_renamed	The team was renamed.
Message edited	@app.on_edit_message	A message was edited.
Message soft deleted	@app.on_soft_delete_message	A message was soft-deleted.
Message undeleted	@app.on_undelete_message	A deleted message was restored.
Meeting started	@app.on_meeting_start	A meeting has started.
Meeting ended	@app.on_meeting_end	A meeting has ended.
Participant joined	@app.on_meeting_participant_join	A participant joined a meeting.
Participant left	@app.on_meeting_participant_leave	A participant left a meeting.

Teams invoke activities

Invoke type	Decorator	Description
CardAction.Invoke	@app.on_card_action	A card action invoke activity was received.
task/fetch	@app.on_dialog_open	A dialog (task module) was fetched.
task/submit	@app.on_dialog_submit	A dialog (task module) was submitted.
fileConsent/invoke	@app.on_file_consent	A file consent card activity was received.
signin/verifyState	Handled automatically by the SDK (OAuth flow)	Sign-in verify state activity.

Now that you've familiarized yourself with agent activity handlers, let us see how agents behave differently depending on the conversation and the messages it receives or sends.

Recommendations

An extensive dialog between your agent and the user is a slow and complex way to get a task completed. An agent that supports excessive commands, especially a broad range of commands, isn't successful or viewed positively by users.

• Avoid multi-turn experiences in chat An extensive dialog requires the developer to maintain state. To exit this state, a user must either time out or select Cancel. Also, the process is tedious. For example, see the following conversation scenario:

  USER: Schedule a meeting with Megan.

  AGENT: I've found 200 results, include a first and last name.

  USER: Schedule a meeting with Megan Bowen.

  AGENT: OK, what time would you like to meet with Megan Bowen?

  USER: 1:00 pm.

  AGENT: On which day?

• Support six or less frequent commands As there are only six visible commands in the current agent menu, anything more is unlikely to be used with any frequency. Agents that go deep into a specific area rather than trying to be a broad assistant work and fare better.

• Optimize size of knowledge base for quicker interaction One of the disadvantages of agents is that it's difficult to maintain a large retrieval knowledge base with unranked responses. Agents are best suited for short, quick interactions, and not sifting through long lists looking for an answer.

Note

Teams platform only supports Transport Layer Security (TLS) version 1.2. Ensure you configure your agent environment accordingly.

Explore other agent features

In addition to conventional agent features, you can also explore advanced features available in a Teams agent app:

• Get Teams specific context for your agent.
• Calls and online meetings agents.
• Enable SSO for your app.

Code sample

Sample name	Description	TypeScript	C#	Python
Teams conversation agent	This app demonstrates basic agent events.	View	View	View