retell_update_phone_number · Retell AI MCP Server MCP

WHAT IT DOES

What retell_update_phone_number does on Retell AI MCP Server

AI agents use retell_update_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_update_phone_number needs a policy

This tool creates or modifies data reversibly (Write category). Updating phone number settings and agent assignments is a reversible configuration change that could redirect inbound calls to different agents, affecting customer interactions and potentially business operations.

From the tool's definition Tool name contains 'update' and description states 'Update settings for a phone number including assigned agents' — this modifies configuration and assignments in a deployed system.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

retell_update_phone_number Rate-limited

retell_update_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_update_phone_number": {
      "limits": [
        {
          "counter": "retell_update_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_update_phone_number

What does the retell_update_phone_number tool do? +

Update settings for a phone number including assigned 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_update_phone_number? +

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

retell_update_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_update_phone_number? +

Yes. Add a rate_limit block to the retell_update_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_update_phone_number completely? +

Set action: deny in the PolicyLayer policy for retell_update_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_update_phone_number? +

retell_update_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.