retell_import_phone_number · Retell AI MCP Server MCP

WHAT IT DOES

What retell_import_phone_number does on Retell AI MCP Server

AI agents use retell_import_phone_number to create or update resources in Retell AI MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Retell AI MCP Server environment.

WHY IT NEEDS A POLICY

Why retell_import_phone_number needs a policy

This tool creates/adds a new phone number resource to the system (Write category). It has high severity because misconfigured phone number imports could enable unauthorized communication channels, cause billing issues, or create service disruptions. However, it is reversible (numbers can be removed), so it is not Destructive.

From the tool's definition Tool performs "Import an existing phone number from an external provider via SIP" - this creates a new phone number resource in the Retell AI system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

retell_import_phone_number Rate-limited

retell_import_phone_number stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "retell_import_phone_number": {
      "limits": [
        {
          "counter": "retell_import_phone_number_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Retell AI MCP Server, so you can run agents against it safely.

FAQ

Questions about retell_import_phone_number

What does the retell_import_phone_number tool do? +

Import an existing phone number from an external provider via SIP. It is categorised as a Write tool in the Retell AI MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on retell_import_phone_number? +

Register the Retell AI MCP Server MCP server in PolicyLayer and add a rule for retell_import_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 Retell AI MCP Server. Nothing to install.

What risk level is retell_import_phone_number? +

retell_import_phone_number is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit retell_import_phone_number? +

Yes. Add a rate_limit block to the retell_import_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.

How do I block retell_import_phone_number completely? +

Set action: deny in the PolicyLayer policy for retell_import_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.

What MCP server provides retell_import_phone_number? +

retell_import_phone_number is provided by the Retell AI MCP Server MCP server (itsanamune/retellsimp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.