npm_create_stream · Nginx Manager MCP: Risk & Policy

WHAT IT DOES

What npm_create_stream does on Nginx Manager

AI agents use npm_create_stream 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_create_stream needs a policy

This tool creates a new TCP/UDP stream configuration in the proxy manager. It is a reversible write operation (the stream can later be deleted), but misuse could expose internal services or open unintended network ports, giving it medium severity.

From the tool's definition "Create a TCP/UDP stream" — creates a new network stream resource in Nginx Proxy Manager

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

npm_create_stream Rate-limited

npm_create_stream 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_create_stream": {
      "limits": [
        {
          "counter": "npm_create_stream_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_create_stream

What does the npm_create_stream tool do? +

Create a TCP/UDP stream. 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_create_stream? +

Register the Nginx Manager MCP server in PolicyLayer and add a rule for npm_create_stream: 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_create_stream? +

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

Can I rate-limit npm_create_stream? +

Yes. Add a rate_limit block to the npm_create_stream 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_create_stream completely? +

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

npm_create_stream 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.