create_user · Nginx Proxy Manager MCP: Risk & Policy

WHAT IT DOES

What create_user does on Nginx Proxy Manager MCP

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

WHY IT NEEDS A POLICY

Why create_user needs a policy

Creating a new user is a reversible write operation that adds a user account to the NPM system. It is not immediately destructive (account can be deleted), not financial, and does not execute arbitrary code. However, it carries high severity because unauthorized user creation could grant administrative access to proxy infrastructure, affecting all proxied services and potentially enabling lateral attacks.

From the tool's definition Tool name 'create_user' and description 'Create a new NPM user' indicate creation of a new user account in Nginx Proxy Manager. This modifies system state by adding authentication credentials and access control.

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 Nginx Proxy Manager MCP, so you can run agents against it safely.

FAQ

Questions about create_user

What does the create_user tool do? +

Create a new NPM user. It is categorised as a Write tool in the Nginx Proxy Manager MCP 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 Nginx Proxy Manager 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 Nginx Proxy Manager MCP. 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 Nginx Proxy Manager MCP server (verybigsad/nginx-proxy-manager-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.