create_user · Microsoft Graph MCP Server MCP: Risk & Policy

WHAT IT DOES

What create_user does on Microsoft Graph MCP Server

AI agents use create_user to create or update resources in Microsoft Graph MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Microsoft Graph MCP Server environment.

WHY IT NEEDS A POLICY

Why create_user needs a policy

This tool creates new user accounts in Microsoft 365, which is a reversible write operation (users can be deleted). However, the blast radius is high because provisioning unauthorized users could grant access to sensitive organizational resources, enable data exfiltration, or create privilege escalation vectors.

From the tool's definition Tool name: 'create_user'. Description: 'Create a new user in Microsoft 365'. The tool creates a new user account, which is a persistent modification of the organization's identity and access management system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_user Rate-limited

create_user stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_user": {
      "limits": [
        {
          "counter": "create_user_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Microsoft Graph MCP Server, so you can run agents against it safely.

FAQ

Questions about create_user

What does the create_user tool do? +

Create a new user in Microsoft 365. It is categorised as a Write tool in the Microsoft Graph MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_user? +

Register the Microsoft Graph MCP Server MCP server in PolicyLayer and add a rule for create_user: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Microsoft Graph MCP Server. Nothing to install.

What risk level is create_user? +

create_user is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_user? +

Yes. Add a rate_limit block to the create_user rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block create_user completely? +

Set action: deny in the PolicyLayer policy for create_user. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides create_user? +

create_user is provided by the Microsoft Graph MCP Server MCP server (ry-ops/microsoft-graph-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.