custom_create_lead_fields
[CUSTOM] Calls the Marketo REST API directly (not Adobe's native MCP).
This record as markdown: /tools/tyron-pretorius-marketo-mcp/custom-create-lead-fields.md
What custom_create_lead_fields does on Marketo MCP Server
AI agents use custom_create_lead_fields 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 custom_create_lead_fields is rated Medium
This tool creates new lead field definitions in Marketo, which is a write operation that modifies the system structure. While reversible (fields can typically be deleted or modified), the impact is moderate—incorrect field creation could affect data collection, reporting, and downstream integrations.
From the tool's definition Tool name 'custom_create_lead_fields' indicates creation of lead field definitions. Description states it 'Calls the Marketo REST API directly,' and the server context shows this is part of a tool set for 'comprehensive management of Marketo assets including…
Attacks that exploit this kind of access
The rule that runs custom_create_lead_fields 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_create_lead_fields, this is the rule to start with:
custom_create_lead_fields 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Marketo MCP Server, apply this rule, and every custom_create_lead_fields call is checked against it from then on.
Questions about custom_create_lead_fields
[CUSTOM] Calls the Marketo REST API directly (not Adobe's native MCP). 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.
Register the Marketo MCP Server MCP server in PolicyLayer and add a rule for custom_create_lead_fields: 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.
custom_create_lead_fields is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the custom_create_lead_fields 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.
Set action: deny in the PolicyLayer policy for custom_create_lead_fields. 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.
custom_create_lead_fields 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.
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