copy_node · Pen MCP: Risk & Policy

WHAT IT DOES

What copy_node does on Pen

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

WHY IT NEEDS A POLICY

Why copy_node needs a policy

The tool creates new nodes (copy operation) and modifies document structure (insertion under parent), both of which are reversible Write operations. It does not execute arbitrary code, delete data irreversibly, or trigger financial transactions.

From the tool's definition Tool performs 'Deep-copy an existing node (with new IDs) and insert the clone under a parent. Optionally apply property overrides' — this creates new data structures reversibly through duplication and insertion operations.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

copy_node Rate-limited

copy_node 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": {
    "copy_node": {
      "limits": [
        {
          "counter": "copy_node_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 Pen, so you can run agents against it safely.

FAQ

Questions about copy_node

What does the copy_node tool do? +

Deep-copy an existing node (with new IDs) and insert the clone under a parent. Optionally apply property overrides. It is categorised as a Write tool in the Pen MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on copy_node? +

Register the Pen MCP server in PolicyLayer and add a rule for copy_node: 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 Pen. Nothing to install.

What risk level is copy_node? +

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

Can I rate-limit copy_node? +

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

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

copy_node is provided by the Pen MCP server (@zseven-w/pen-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.