create_list · Campaign Monitor MCP: Risk & Policy

WHAT IT DOES

What create_list does on Campaign Monitor MCP

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

WHY IT NEEDS A POLICY

Why create_list needs a policy

Creating a new subscriber list is a Write operation—it adds data to the system but does not execute arbitrary code, delete data, move money, or cause irreversible harm. The blast radius is low because list creation can be undone by deleting the list. A misconfigured AI agent creating unwanted lists would be a minor operational inconvenience rather than a security breach.

From the tool's definition Tool name is 'create_list' and description states 'Create a new subscriber list'. The verb 'create' indicates a reversible modification operation that adds a new resource.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_list Rate-limited

create_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": {
    "create_list": {
      "limits": [
        {
          "counter": "create_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 Campaign Monitor MCP, so you can run agents against it safely.

FAQ

Questions about create_list

What does the create_list tool do? +

Create a new subscriber list. It is categorised as a Write tool in the Campaign Monitor MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_list? +

Register the Campaign Monitor MCP server in PolicyLayer and add a rule for create_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 Campaign Monitor MCP. Nothing to install.

What risk level is create_list? +

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

Can I rate-limit create_list? +

Yes. Add a rate_limit block to the create_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 create_list completely? +

Set action: deny in the PolicyLayer policy for create_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 create_list? +

create_list is provided by the Campaign Monitor MCP server (pauliowest/cmon-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.