Microsoft Teams Bot Without an SDK

medium20 minteams-bot.ts

You want an agent in Microsoft Teams that answers personal chats and @mentions in channels, asks before risky tools run, and does not pull in botbuilder.

What it shows

Run a Gateway with teamsChannel(): Bot Framework posts activities to /api/messages, answers go to the Bot Connector
Every request is checked against its signed JWT: RS256, issuer, App ID audience, expiry, service URL and the msteams endorsement
Each personal chat, group chat and channel thread is a conversation of its own, and the mention of the bot is stripped
Answers stream into a message it edits, spaced under the 7 messages a second Teams allows per chat
Approval prompts get Approve and Deny buttons as an Adaptive Card with Action.Execute

The code

teams-bot.ts

import { Agent, Cogitator } from '@cogitator-ai/core';
import { Gateway, teamsChannel } from '@cogitator-ai/channels';

const appId = process.env.TEAMS_APP_ID;
const appPassword = process.env.TEAMS_APP_PASSWORD;
const tenantId = process.env.TEAMS_TENANT_ID;
const apiKey = process.env.GOOGLE_API_KEY;
if (!appId || !appPassword || !tenantId || !apiKey) {
  throw new Error('Set TEAMS_APP_ID, TEAMS_APP_PASSWORD, TEAMS_TENANT_ID and GOOGLE_API_KEY');
}

const teams = teamsChannel({ appId, appPassword, tenantId, webhook: { port: 3978 } });

const agent = new Agent({
  name: 'teams-assistant',
  model: 'google/gemini-3.5-flash-lite',
  instructions: 'You help a team in Microsoft Teams. Be brief and use Markdown.',
});

const cogitator = new Cogitator({
  llm: { providers: { google: { apiKey } } },
  memory: { adapter: 'memory' },
});
const memory = await cogitator.getMemory();

const gateway = new Gateway({
  agent,
  cogitator,
  channels: [teams],
  ...(memory && { memory }),
  stream: { flushInterval: 600, minChunkSize: 40 },
});

await gateway.start();
console.log('Teams messaging endpoint at http://localhost:3978/api/messages');

Run it

install · bash

pnpm add @cogitator-ai/core @cogitator-ai/channels

EnvironmentTEAMS_APP_IDTEAMS_APP_PASSWORDTEAMS_TENANT_IDGOOGLE_API_KEY

run · bash

npx tsx teams-bot.ts

Or run the full example from a clone of the repository (keys in .env):

repository · bash

npx tsx examples/channels/08-teams-bot.ts

Microsoft Teams Bot Without an SDK

What it shows

The code

Run it

Learn more