sms_cancel_scheduled
AI agents call sms_cancel_scheduled to permanently remove resources in Twilio SMS MCP Server — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Canceling a scheduled message is likely irreversible — once canceled, the scheduled send cannot be undone. The name strongly implies cancellation of a previously scheduled operation. Description is empty, which lowers confidence, but given the server context and naming convention, this is most likely a destructive/irreversible action.
From the tool's definition Tool name 'sms_cancel_scheduled' on a server that handles scheduled SMS/MMS messaging; description is empty
Attacks that exploit this kind of access
sms_cancel_scheduled. It is categorised as a Destructive tool in the Twilio SMS MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the Twilio SMS MCP Server MCP server in PolicyLayer and add a rule for sms_cancel_scheduled: 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 Twilio SMS MCP Server. Nothing to install.
sms_cancel_scheduled 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 sms_cancel_scheduled 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 sms_cancel_scheduled. 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.
sms_cancel_scheduled is provided by the Twilio SMS MCP Server MCP server (0x-professor/twilio-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
sms_cancel_scheduled is one line of Twilio SMS MCP Server's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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