Secure Authentication for Autonomous Agents in Copilot Studio

Summary

  • Autonomous agents run in the background without user prompts, so they cannot ask users to sign in during execution.
  • Use maker-provided credentials for tools; user credentials are not appropriate for autonomous scenarios.
  • Apply least privilege and restrict tool actions to reduce data exposure and abuse.
  • Communicate the “runs under author’s identity” warning and govern access like any service account.

Table of Contents

Why Authentication Matters

As organizations adopt autonomous agents to perform tasks and make decisions, authentication becomes a core control. Proper auth ensures agents act with a known identity, within approved boundaries, and leave auditable traces. Misconfigured auth can lead to over‑privileged actions, data exfiltration, and non‑compliant behavior.

Autonomous Agents: What Changes

Autonomous agents execute without user interaction and often on triggers (e.g., “when a new email arrives”). This has key implications:

  • No interactive sign‑in: agents cannot prompt users to authenticate mid‑flow.
  • Background execution: all tool calls must succeed using pre‑configured credentials.
  • Clear scope: actions should be constrained to well‑defined, non‑sensitive operations.

Authentication Models

Copilot Studio tools support two auth patterns:

  • Maker‑provided credentials: the tool runs under the author’s configured identity (service‑account style). Required for autonomous agents.
  • User credentials: the tool impersonates the signed‑in end user. Not applicable to autonomous agents because there is no interactive user session.

Important: For autonomous agents, always use maker‑provided credentials. Treat them like service accounts: minimize privileges, monitor usage, and rotate secrets.

Configure Tool Authentication

Example scenario: a holiday‑planning autonomous agent that receives email queries and responds via email using an Email Management connector.

Steps:

  1. Create the agent and add a trigger (e.g., “When a new email arrives”).
  2. Add tools:
    • A prompt tool (no auth required) for “Detailed Travel Plan” instructions.
    • An email tool to send responses back to the requester.
  3. In the email tool, select Maker‑provided credentials and configure the connector identity.
  4. In the agent instructions, explicitly state it runs autonomously and does not wait for user input.

Restrict Tool Actions

Restrict actions to reduce blast radius. For the Email Management connector (NCB server), disable all actions except what you truly need:

  • Enable only: Reply to email, Send email.
  • Disable: List emails, Get email, and similar read operations that could expose sensitive inbox content.

This prevents “prompt‑injection” or jailbreak attempts from coercing the agent to enumerate mailboxes or leak data. Combine with content filters and pattern checks to detect suspicious instructions.

Email MCP Server

Publishing, Warnings, and Governance

When an agent using maker‑provided credentials is published, end users may see a warning that it runs under the author’s identity. Treat this as a governance control:

  • Document the identity used and its permissions.
  • Limit where the agent is available (internal only if it handles sensitive data).
  • Maintain audit trails: capture tool activity logs and outcomes.
  • Apply environment separation (Dev/Test/Prod) and approval workflows for changes.

Warning publishing autonomous agents

Demo

Avoid Security Risks! Authentication for Autonomous Agents in Copilot Studio