token.provision · Ngsrv MCP: Risk & Policy

WHAT IT DOES

What token.provision does on Ngsrv

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

WHY IT NEEDS A POLICY

Why token.provision needs a policy

This tool creates/provisions a new authentication token, which is a Write operation (creating a credential). It does not delete or overwrite existing data, and is reversible in the sense that the token expires after 12 hours. However, misuse could allow unauthorized tunnel creation, giving it medium severity — a provisioned token grants access to start/stop tunnels and expose local services publicly.

From the tool's definition Obtain a 12-hour ngsrv agent token for tunnel commands

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

token.provision Rate-limited

token.provision 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": {
    "token.provision": {
      "limits": [
        {
          "counter": "token.provision_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 Ngsrv, so you can run agents against it safely.

FAQ

Questions about token.provision

What does the token.provision tool do? +

Obtain a 12-hour ngsrv agent token for tunnel commands. It is categorised as a Write tool in the Ngsrv MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on token.provision? +

Register the Ngsrv MCP server in PolicyLayer and add a rule for token.provision: 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 Ngsrv. Nothing to install.

What risk level is token.provision? +

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

Can I rate-limit token.provision? +

Yes. Add a rate_limit block to the token.provision 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 token.provision completely? +

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

token.provision is provided by the Ngsrv MCP server (ngsrv/ngsrv-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.