create_rest_message · ServiceNow- MCP: Risk & Policy

WHAT IT DOES

What create_rest_message does on ServiceNow-MCP

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

WHY IT NEEDS A POLICY

Why create_rest_message needs a policy

This tool creates new REST message definitions in ServiceNow, which are configuration objects that define outbound integrations and API calls. While reversible (can be deleted), creating REST messages can establish new external integrations, webhooks, or API endpoints that could be exploited to exfiltrate data or trigger malicious actions if misconfigured by an AI agent.

From the tool's definition Tool name 'create_rest_message' and description 'Create a new outbound REST Message definition' indicate creation of new configuration objects in ServiceNow.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_rest_message Rate-limited

create_rest_message 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_rest_message": {
      "limits": [
        {
          "counter": "create_rest_message_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 ServiceNow-MCP, so you can run agents against it safely.

FAQ

Questions about create_rest_message

What does the create_rest_message tool do? +

Create a new outbound REST Message definition (requires WRITE_ENABLED=true). It is categorised as a Write tool in the ServiceNow-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_rest_message? +

Register the ServiceNow- MCP server in PolicyLayer and add a rule for create_rest_message: 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 ServiceNow-MCP. Nothing to install.

What risk level is create_rest_message? +

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

Can I rate-limit create_rest_message? +

Yes. Add a rate_limit block to the create_rest_message 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_rest_message completely? +

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

create_rest_message is provided by the ServiceNow- MCP server (tedorigawa001/servicenow-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.