set_primary_contact · Campaign Monitor MCP: Risk & Policy

WHAT IT DOES

What set_primary_contact does on Campaign Monitor MCP

AI agents use set_primary_contact 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 set_primary_contact needs a policy

This tool modifies account settings (primary contact information) but does not delete data, execute arbitrary code, move funds, or trigger external operations with unpredictable effects. It is a Write operation that changes account configuration reversibly.

From the tool's definition Tool name 'set_primary_contact' and description 'Set the primary contact for the account' indicate modification of account metadata. This is a reversible change to account configuration.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_primary_contact Rate-limited

set_primary_contact 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": {
    "set_primary_contact": {
      "limits": [
        {
          "counter": "set_primary_contact_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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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 set_primary_contact

What does the set_primary_contact tool do? +

Set the primary contact for the account. 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 set_primary_contact? +

Register the Campaign Monitor MCP server in PolicyLayer and add a rule for set_primary_contact: 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 set_primary_contact? +

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

Can I rate-limit set_primary_contact? +

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

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

set_primary_contact 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.