Delete a calendar event. notify_attendees controls whether cancellation emails are sent.
AI agents call cancel_event to permanently remove resources in Nexus Core — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Deleting a calendar event is an irreversible destructive action that removes data and cannot be undone by the tool itself. Unlike Write operations (create/update), deletion is permanent. The blast radius is high because a misbehaving agent could cancel important meetings, affecting multiple attendees and business continuity.
From the tool's definition 'Delete a calendar event' — the tool irreversibly removes calendar data. The notify_attendees parameter indicates this affects external parties (attendees receive cancellation notices), amplifying impact.
Attacks that exploit this kind of access
Delete a calendar event. notify_attendees controls whether cancellation emails are sent. It is categorised as a Destructive tool in the Nexus Core MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Nexus Core MCP server in PolicyLayer and add a rule for cancel_event: 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 Nexus Core. Nothing to install.
cancel_event 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 cancel_event 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 cancel_event. 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.
cancel_event is provided by the Nexus Core MCP server (noumenon-ai/nexus-core). 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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