# custom_create_lead_fields

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

Agent View of the PolicyLayer registry record for `custom_create_lead_fields`. HTML page: https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-create-lead-fields

## Facts

- Tool: `custom_create_lead_fields`
- Server: Marketo MCP Server (`tyron-pretorius/marketo-mcp`) — https://policylayer.com/tools/tyron-pretorius-marketo-mcp.md
- Homepage: https://github.com/tyron-pretorius/marketo-mcp
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "custom_create_lead_fields",
    "arguments": {}
  }
}
```

## 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 own 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…"

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Marketo MCP Server:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "custom_create_lead_fields": {
      "limits": [
        {
          "counter": "custom_create_lead_fields_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Marketo MCP Server (297)

- `custom_cancel_lead_export_job` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-cancel-lead-export-job.md
- `custom_delete_companies` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-companies.md
- `custom_delete_custom_activity_type` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-custom-activity-type.md
- `custom_delete_custom_activity_type_attributes` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-custom-activity-type-attributes.md
- `custom_delete_custom_object_type` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-custom-object-type.md
- `custom_delete_custom_object_type_fields` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-custom-object-type-fields.md
- `custom_delete_custom_objects` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-custom-objects.md
- `custom_delete_email` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-email.md
- `custom_delete_email_module` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-email-module.md
- `custom_delete_email_template` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-email-template.md
- `custom_delete_email_template2` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-email-template2.md
- `custom_delete_email2` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-email2.md
- `custom_delete_folder` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-folder.md
- `custom_delete_form` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-form.md
- `custom_delete_form_field` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-form-field.md
- `custom_delete_form_fieldset_field` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-form-fieldset-field.md
- `custom_delete_fragment` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-fragment.md
- `custom_delete_landing_page` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-landing-page.md
- `custom_delete_landing_page_content_section` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-landing-page-content-section.md
- `custom_delete_landing_page_template` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-landing-page-template.md
- `custom_delete_leads` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-leads.md
- `custom_delete_named_account_lists` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-named-account-lists.md
- `custom_delete_named_accounts` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-named-accounts.md
- `custom_delete_opportunities` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-opportunities.md
- `custom_delete_opportunity_roles` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-opportunity-roles.md
- `custom_delete_program` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-program.md
- `custom_delete_program_members` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-program-members.md
- `custom_delete_redirect_rule` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-redirect-rule.md
- `custom_delete_sales_persons` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-sales-persons.md
- `custom_delete_smart_campaign` — Destructive — https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-delete-smart-campaign.md
- …and 267 more: https://policylayer.com/tools/tyron-pretorius-marketo-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=tyron-pretorius-marketo-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/tyron-pretorius-marketo-mcp