Delete a custom field by ID.
AI agents call delete_custom_field to permanently remove resources in Mycase — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
This tool permanently removes a custom field from the law firm's MyCase account. Deletion is irreversible and cannot be undone. While the blast radius is scoped to a single custom field (not a catastrophic wipe), the loss of custom field definitions could disrupt case management workflows and data organization for the firm. This qualifies as Destructive rather than Write because the action cannot be reversed.
From the tool's definition Tool name is 'delete_custom_field' with description 'Delete a custom field by ID.' The verb 'delete' indicates irreversible removal of data.
Attacks that exploit this kind of access
Delete a custom field by ID. It is categorised as a Destructive tool in the Mycase MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Mycase 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 Mycase. 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 Mycase MCP server (rosenadvertising/mycase-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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