createSystemUser | PolicyLayer

WHAT IT DOES

What createSystemUser does on Dynamics 365 Finance & Operations MCP Server

AI agents use createSystemUser to create or update resources in Dynamics 365 Finance & Operations MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Dynamics 365 Finance & Operations MCP Server environment.

WHY IT NEEDS A POLICY

Why createSystemUser needs a policy

This tool creates new system users, which is a write operation that adds data to the system. It does not delete data (ruling out Destructive), does not move money (ruling out Financial), and does not execute arbitrary code (ruling out Execute).

From the tool's definition The tool name 'createSystemUser' and description 'Creates a new user in SystemUsers' indicate creation of a new entity in a system directory. This is a reversible write operation that modifies system state by adding a user account.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

createSystemUser Rate-limited

createSystemUser 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": {
    "createSystemUser": {
      "limits": [
        {
          "counter": "createsystemuser_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 Dynamics 365 Finance & Operations MCP Server, so you can run agents against it safely.

FAQ

Questions about createSystemUser

What does the createSystemUser tool do? +

Creates a new user in SystemUsers. It is categorised as a Write tool in the Dynamics 365 Finance & Operations 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 createSystemUser? +

Register the Dynamics 365 Finance & Operations MCP Server MCP server in PolicyLayer and add a rule for createSystemUser: 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 Dynamics 365 Finance & Operations MCP Server. Nothing to install.

What risk level is createSystemUser? +

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

Can I rate-limit createSystemUser? +

Yes. Add a rate_limit block to the createSystemUser 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 createSystemUser completely? +

Set action: deny in the PolicyLayer policy for createSystemUser. 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 createSystemUser? +

createSystemUser is provided by the Dynamics 365 Finance & Operations MCP Server MCP server (sahib-sawhney-wh/fno-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.