Update phone number configuration
Risk signalsChanges call/SMS routing for number
Part of the Twilio server.
Free to start. No card required.
AI agents use update_incoming_phone_number to create or modify resources in Twilio. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call update_incoming_phone_number repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Twilio.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"update_incoming_phone_number": {
"limits": [
{
"counter": "update_incoming_phone_number_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Twilio policy for all 36 tools.
These attack patterns abuse exactly the kind of access update_incoming_phone_number gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Update phone number configuration. It is categorised as a Write tool in the Twilio MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Twilio MCP server in PolicyLayer and add a rule for update_incoming_phone_number: 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. Nothing to install.
update_incoming_phone_number is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the update_incoming_phone_number 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 update_incoming_phone_number. 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.
update_incoming_phone_number is provided by the Twilio MCP server (@twilio-labs/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 36 Twilio tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.