# custom_update_custom_object_type_field

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

Agent View of the PolicyLayer registry record for `custom_update_custom_object_type_field`. HTML page: https://policylayer.com/tools/tyron-pretorius-marketo-mcp/custom-update-custom-object-type-field

## Facts

- Tool: `custom_update_custom_object_type_field`
- 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_update_custom_object_type_field",
    "arguments": {}
  }
}
```

## Why custom_update_custom_object_type_field is rated Medium

This tool creates or modifies custom object type field definitions in Marketo, which is reversible but impacts data structure and configuration. It falls under Write rather than Execute because it targets a specific data modification (field updates) rather than arbitrary code execution or campaign triggering.

From the tool's own definition: "Tool name contains 'update' and 'custom_object_type_field'; description indicates it calls Marketo REST API directly to modify custom object type fields."

## Use case

AI agents use custom_update_custom_object_type_field 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_update_custom_object_type_field": {
      "limits": [
        {
          "counter": "custom_update_custom_object_type_field_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