delete_custom_field
Delete a custom field definition and its stored values.
This record as markdown: /tools/io-favcrm-favcrm/delete-custom-field.md
What delete_custom_field does on FavCRM
AI agents call delete_custom_field to permanently remove resources in FavCRM, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
| Parameter | Type | Required | Description |
|---|---|---|---|
definitionId | string | Yes | Custom field definition ID |
Parameters from the server's own tool schema.
Why delete_custom_field is rated Critical
This tool meets the Destructive category because it permanently removes data without the ability to undo the action. Deleting a custom field definition along with all stored values across potentially many records in a CRM represents irreversible data loss. The high severity reflects the blast radius in a CRM context where custom fields often store critical business data (customer preferences, service details, etc.).
From the tool's definition delete_custom_field performs an irreversible deletion operation: 'Delete a custom field definition and its stored values.' This removes both the schema definition and all associated data.
Attacks that exploit this kind of access
The rule that runs delete_custom_field safely
PolicyLayer is an MCP gateway: it sits between your AI agents and FavCRM, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For delete_custom_field, this is the rule to start with:
delete_custom_field is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect FavCRM, apply this rule, and every delete_custom_field call is checked against it from then on.
Questions about delete_custom_field
Delete a custom field definition and its stored values. It is categorised as a Destructive tool in the FavCRM MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
delete_custom_field accepts 1 parameter: definitionId. Required: definitionId. The full parameter table on this page comes from the server's own tool schema.
Register the FavCRM MCP server in PolicyLayer and add a rule for delete_custom_field: 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 FavCRM. Nothing to install.
delete_custom_field is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the delete_custom_field 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 delete_custom_field. 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.
delete_custom_field is provided by the FavCRM MCP server (https://api.favcrm.io/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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