Arcetec — AI Agents in Microsoft Teams with Certificate-Based Identity

The challenge

The internal agent that handles and carries out work from Teams and email relied on browser-based authentication and a shared hosting environment whose firewall blocked operations.

The solution

It was moved to NestJS 11 and Prisma on Azure, with server-side sign-in, an RSA certificate instead of secrets, permission levels in the database, and a session verified against Microsoft every 30 minutes. The agent uses Teams bots with adaptive cards, Exchange, SharePoint, and Azure DevOps, and works with Claude, OpenAI, and Gemini. It is backed by 59 migrations, 120 test files, and continuous integration in Azure DevOps.

Technologies used

• NestJS
• Microsoft Teams
• Microsoft Entra ID
• Microsoft Graph
• Azure DevOps
• Claude

Results

• 30 min Verification with Microsoft — For every session
• 120 Test files
• 59 Database migrations