retell_create_phone_number · Retell AI MCP Server MCP

WHAT IT DOES

What retell_create_phone_number does on Retell AI MCP Server

AI agents use retell_create_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_create_phone_number needs a policy

While this tool involves purchasing (which could suggest Financial category), the primary action is creating/registering a resource in the system. However, the 'purchase' component introduces financial commitment. Classified as Write rather than Financial because the tool's main function is resource creation in the platform; the financial aspect is secondary/incidental to the registration process.

From the tool's definition Tool description states 'Register/purchase a new phone number' — this creates a new resource (phone number registration) and involves a financial transaction (purchase).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

retell_create_phone_number Rate-limited

retell_create_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_create_phone_number": {
      "limits": [
        {
          "counter": "retell_create_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_create_phone_number

What does the retell_create_phone_number tool do? +

Register/purchase a new phone number for use with Retell AI agents. 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_create_phone_number? +

Register the Retell AI MCP Server MCP server in PolicyLayer and add a rule for retell_create_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_create_phone_number? +

retell_create_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_create_phone_number? +

Yes. Add a rate_limit block to the retell_create_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_create_phone_number completely? +

Set action: deny in the PolicyLayer policy for retell_create_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_create_phone_number? +

retell_create_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.