Delete a CalDAV event by its href.
AI agents call calendar_delete_event to permanently remove resources in Pyfastmail — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
This tool permanently removes calendar events without possibility of recovery. While the blast radius is scoped to calendar data (not system-wide or financial), calendar events are important commitments and appointments that cannot be undone once deleted. An AI agent with access could maliciously or accidentally erase user schedules, meetings, and time-sensitive information.
From the tool's definition Tool name contains 'delete' and description states 'Delete a CalDAV event by its href' — deletion is irreversible data removal.
Attacks that exploit this kind of access
Delete a CalDAV event by its href. It is categorised as a Destructive tool in the Pyfastmail MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Pyfastmail MCP server in PolicyLayer and add a rule for calendar_delete_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 Pyfastmail. Nothing to install.
calendar_delete_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 calendar_delete_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 calendar_delete_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.
calendar_delete_event is provided by the Pyfastmail MCP server (pjosols/pyfastmail-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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