AI agents call vapi_get_phone_number to retrieve information from Mcp Vapi without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about a phone number resource. It performs a query/fetch operation with no side effects—no data is created, modified, deleted, or financial obligations are incurred. The blast radius of misuse is minimal; an attacker could only view phone number details already accessible to the authenticated account.
From the tool's definition Tool name 'vapi_get_phone_number' and description 'Get details of a specific Vapi phone number' indicate a retrieval operation with no modification or deletion of data.
Attacks that exploit this kind of access
Get details of a specific Vapi phone number. It is categorised as a Read tool in the Mcp Vapi MCP Server, which means it retrieves data without modifying state.
Register the Mcp Vapi MCP server in PolicyLayer and add a rule for vapi_get_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 Mcp Vapi. Nothing to install.
vapi_get_phone_number 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 vapi_get_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.
Set action: deny in the PolicyLayer policy for vapi_get_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.
vapi_get_phone_number is provided by the Mcp Vapi MCP server (adhirajhangal/mcp-vapi). 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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