AI agents call vapi_list_assistants 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 and queries existing voice assistant metadata from the Vapi account without creating, modifying, deleting, or executing any operations. It is a read-only operation with minimal security risk, as it only exposes information about assistants the user already has access to manage.
From the tool's definition Tool description states "List all voice assistants in your Vapi account. Returns IDs, names, and config." The verb "List" and "Returns" indicate data retrieval with no modification or execution of external operations.
Attacks that exploit this kind of access
List all voice assistants in your Vapi account. Returns IDs, names, and config. 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_list_assistants: 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_list_assistants 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_list_assistants 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_list_assistants. 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_list_assistants 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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