custom_sync_leads · Marketo MCP Server MCP: Risk & Policy

WHAT IT DOES

What custom_sync_leads does on Marketo MCP Server

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

WHY IT NEEDS A POLICY

Why custom_sync_leads needs a policy

The name 'custom_sync_leads' implies a sync operation on leads, which in Marketo's REST API context typically means upsert (create or update) operations on lead records. This falls under Write as it modifies CRM/marketing data. Without a description, confidence is reduced, but the Marketo API's syncLeads endpoint is well-known for creating/updating leads.

From the tool's definition Tool name 'custom_sync_leads' suggests synchronizing lead data; 'sync' typically implies creating or updating records. Description is empty, lowering confidence.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

custom_sync_leads Rate-limited

custom_sync_leads 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": {
    "custom_sync_leads": {
      "limits": [
        {
          "counter": "custom_sync_leads_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 Marketo MCP Server, so you can run agents against it safely.

FAQ

Questions about custom_sync_leads

What does the custom_sync_leads tool do? +

custom_sync_leads. It is categorised as a Write tool in the Marketo MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on custom_sync_leads? +

Register the Marketo MCP Server MCP server in PolicyLayer and add a rule for custom_sync_leads: 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_sync_leads? +

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

Can I rate-limit custom_sync_leads? +

Yes. Add a rate_limit block to the custom_sync_leads 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_sync_leads completely? +

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

custom_sync_leads 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.