add_page · Pen MCP: Risk & Policy

WHAT IT DOES

What add_page does on Pen

AI agents use add_page 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 add_page needs a policy

This tool creates and modifies document structure within an OpenPencil file by adding pages and potentially reorganizing existing content. It is reversible (pages can be deleted), so it falls under Write rather than Destructive. The severity is medium because misuse could corrupt document organization, but the effect is not irreversible and not as critical as code execution or data deletion.

From the tool's definition Tool description states 'Add a new page to an .op file' and mentions automatic migration of children, indicating creation of new document structure and modification of existing document state.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_page Rate-limited

add_page 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": {
    "add_page": {
      "limits": [
        {
          "counter": "add_page_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 add_page

What does the add_page tool do? +

Add a new page to an .op file. If the document has no pages yet, the existing children are migrated to the first page automatically. 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 add_page? +

Register the Pen MCP server in PolicyLayer and add a rule for add_page: 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 add_page? +

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

Can I rate-limit add_page? +

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

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

add_page 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.