AI agents call deleteOneCalendarEvent to permanently remove resources in Twenty MCP Server — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
The tool permanently removes a calendar event from the CRM system. Deletion cannot be undone and represents irreversible data loss. While the blast radius is limited to a single event (not system-wide), the permanent nature of deletion and the potential business impact of losing calendar records (meeting schedules, commitments, audit trails) justifies 'high' severity.
From the tool's definition Tool name explicitly contains 'deleteOne' and description states 'Delete One calendarEvent'. This is an irreversible deletion operation.
Documented attack patterns abuse exactly the kind of access deleteOneCalendarEvent gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Twenty MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for deleteOneCalendarEvent:
{
"version": "1",
"default": "deny",
"hide": [
"deleteOneCalendarEvent"
]
}deleteOneCalendarEvent disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.
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Delete One calendarEvent. It is categorised as a Destructive tool in the Twenty MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Twenty MCP Server MCP server in PolicyLayer and add a rule for deleteOneCalendarEvent: 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 Twenty MCP Server. Nothing to install.
deleteOneCalendarEvent 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 deleteOneCalendarEvent 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 deleteOneCalendarEvent. 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.
deleteOneCalendarEvent is provided by the Twenty MCP Server MCP server (jdu278/twenty-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Twenty MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
219 Twenty MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.