List all phone numbers registered with your Retell account.
AI agents call retell_list_phone_numbers to retrieve information from Retell AI MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries existing data (phone numbers) from the Retell account without creating, modifying, or deleting any resources. It is a read-only operation with minimal blast radius if misused by an AI agent, as it only exposes informational data about registered phone numbers.
From the tool's definition Tool name contains 'list' and description states 'List all phone numbers registered with your Retell account' - a retrieval operation with no modification or side effects.
Attacks that exploit this kind of access
List all phone numbers registered with your Retell account. It is categorised as a Read tool in the Retell AI MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Retell AI MCP Server MCP server in PolicyLayer and add a rule for retell_list_phone_numbers: 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.
retell_list_phone_numbers is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the retell_list_phone_numbers 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 retell_list_phone_numbers. 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.
retell_list_phone_numbers 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.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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