npm_update_access_list · Nginx Manager MCP: Risk & Policy

WHAT IT DOES

What npm_update_access_list does on Nginx Manager

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

WHY IT NEEDS A POLICY

Why npm_update_access_list needs a policy

This tool modifies access list configurations, which are reversible changes to security rules. While not destructive (changes can be undone), it does alter existing data structures that control network access. The severity is medium because misuse could expand or restrict access inappropriately, potentially causing service disruption or security gaps, but the effects are not permanent or financially damaging.

From the tool's definition Tool name contains 'update' and description states 'Update an access list', indicating modification of existing data. The tool is part of an Nginx Proxy Manager API abstraction that manages access control rules.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

npm_update_access_list Rate-limited

npm_update_access_list 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": {
    "npm_update_access_list": {
      "limits": [
        {
          "counter": "npm_update_access_list_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 Manager, so you can run agents against it safely.

FAQ

Questions about npm_update_access_list

What does the npm_update_access_list tool do? +

Update an access list. It is categorised as a Write tool in the Nginx Manager MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on npm_update_access_list? +

Register the Nginx Manager MCP server in PolicyLayer and add a rule for npm_update_access_list: 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 Manager. Nothing to install.

What risk level is npm_update_access_list? +

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

Can I rate-limit npm_update_access_list? +

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

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

npm_update_access_list is provided by the Nginx Manager MCP server (kognar-ai/ngnix-manager-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.