publish_journey_event · Campaign Monitor MCP: Risk & Policy

WHAT IT DOES

What publish_journey_event does on Campaign Monitor MCP

AI agents invoke publish_journey_event to trigger actions in Campaign Monitor MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why publish_journey_event needs a policy

This tool triggers an external operation (publishing an event) that initiates a journey workflow for subscribers. It causes downstream automated actions (emails, sequences) to execute, making it an Execute-category tool. Misuse could trigger unintended mass communications to subscribers, hence high severity.

From the tool's definition Publish an event to trigger a subscriber activity journey

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

publish_journey_event Rate-limited

publish_journey_event stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "publish_journey_event": {
      "limits": [
        {
          "counter": "publish_journey_event_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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 publish_journey_event

What does the publish_journey_event tool do? +

Publish an event to trigger a subscriber activity journey. event_data must be a JSON string with the structure: {. It is categorised as a Execute tool in the Campaign Monitor MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on publish_journey_event? +

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

publish_journey_event is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit publish_journey_event? +

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

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

publish_journey_event 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.