custom_list_users

[CUSTOM] Calls the Marketo REST API directly (not Adobe's native MCP).

SERVERMarketo MCP Server SOURCEtyron-pretorius/marketo-mcp

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/tyron-pretorius-marketo-mcp/custom-list-users.md

WHAT IT DOES

What custom_list_users does on Marketo MCP Server

AI agents call custom_list_users to retrieve information from Marketo MCP Server without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why custom_list_users is rated Low

The tool lists or retrieves user data from Marketo. While it is a read operation (low severity baseline), the medium severity is justified because unrestricted access to user lists in a marketing platform could expose sensitive PII (email addresses, contact information, behavioral data) at scale.

From the tool's definition Tool name 'custom_list_users' indicates a listing/query operation. Description states it 'Calls the Marketo REST API directly,' which is a read operation that retrieves user data without modifying it.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs custom_list_users safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Marketo MCP Server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For custom_list_users, this is the rule to start with:

custom_list_users Allowed

custom_list_users is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "custom_list_users": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Marketo MCP Server, apply this rule, and every custom_list_users call is checked against it from then on.

FAQ

Questions about custom_list_users

What does the custom_list_users tool do? +

[CUSTOM] Calls the Marketo REST API directly (not Adobe's native MCP). It is categorised as a Read tool in the Marketo MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on custom_list_users? +

Register the Marketo MCP Server MCP server in PolicyLayer and add a rule for custom_list_users: 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 Marketo MCP Server. Nothing to install.

What risk level is custom_list_users? +

custom_list_users is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit custom_list_users? +

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

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

custom_list_users is provided by the Marketo MCP Server MCP server (tyron-pretorius/marketo-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Marketo MCP Server, and thousands of servers like it.

This server

All 298 Marketo MCP Server tools →

Across the catalogue

aiva_list_affiliates on AIVA MCP Server →list_circuits on 0gzk →list_agents on 0rca Dojo MCP Server → The MCP Attack Database →

Guides

Roll out MCP under one policy →Data exfiltration →MCP token cost →