This record as markdown: /tools/eyalm321-zernio-mcp/zernio-delete-custom-field.md
What zernio_delete_custom_field does on Zernio
AI agents call zernio_delete_custom_field to permanently remove resources in Zernio, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Why zernio_delete_custom_field is rated Critical
Deleting a custom contact field removes data that cannot be recovered. While scoped to a single field rather than entire contacts or databases, the irreversible nature of deletion and potential impact on contact data management workflows (dependent fields, lost historical data) makes this Destructive. This is more severe than Write (which is reversible) and ranks highest among the available categories.
From the tool's definition Tool name explicitly includes 'delete'; description states 'Delete a custom contact field' — this is an irreversible deletion operation.
Attacks that exploit this kind of access
The rule that runs zernio_delete_custom_field safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Zernio, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For zernio_delete_custom_field, this is the rule to start with:
zernio_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 Zernio, apply this rule, and every zernio_delete_custom_field call is checked against it from then on.
Questions about zernio_delete_custom_field
Delete a custom contact field. It is categorised as a Destructive tool in the Zernio MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Zernio MCP server in PolicyLayer and add a rule for zernio_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 Zernio. Nothing to install.
zernio_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 zernio_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 zernio_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.
zernio_delete_custom_field is provided by the Zernio MCP server (eyalm321/zernio-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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