update_phone_number · RetellAI MCP Server MCP: Risk & Policy

WHAT IT DOES

What update_phone_number does on RetellAI MCP Server

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

WHY IT NEEDS A POLICY

Why update_phone_number needs a policy

This tool modifies phone number configuration in a voice service platform, which is a reversible Write operation. The severity is medium because misconfiguration could disrupt communications or redirect calls, but the action itself is not destructive and does not involve financial transactions. The confidence is high based on clear language indicating data modification rather than retrieval or deletion.

From the tool's definition Tool name 'update_phone_number' and description 'Updates a phone number' indicate modification of existing data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

update_phone_number Rate-limited

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": {
    "update_phone_number": {
      "limits": [
        {
          "counter": "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 RetellAI MCP Server, so you can run agents against it safely.

FAQ

Questions about update_phone_number

What does the update_phone_number tool do? +

Updates a phone number. It is categorised as a Write tool in the RetellAI 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 update_phone_number? +

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

What risk level is update_phone_number? +

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 update_phone_number? +

Yes. Add a rate_limit block to the 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 update_phone_number completely? +

Set action: deny in the PolicyLayer policy for 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 update_phone_number? +

update_phone_number is provided by the RetellAI MCP Server MCP server (kuba2290/abhaybabbar_retellai-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.