List available TTS voices for different providers. Args: provider: Optional provider name ('openai' or 'kokoro'). If not specified, lists all available voices. Returns: A formatted list of available voices by provider.
AI agents call list_tts_voices to retrieve information from Voice Mode without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves information about available text-to-speech voice options without modifying any state, executing commands, or triggering external side effects. It is a straightforward data retrieval operation with minimal security risk. The low severity reflects that misuse would only expose informational metadata about available voices, not sensitive data or system capabilities.
From the tool's definition Tool description states it "List[s] available TTS voices" and "Returns a formatted list of available voices by provider." The verb 'list' and the return of existing configuration data with no modification capability indicates a retrieval operation.
Documented attack patterns abuse exactly the kind of access list_tts_voices gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Voice Mode, and nothing reaches the server without passing your rules. This is the rule we recommend for list_tts_voices:
{
"version": "1",
"default": "deny",
"tools": {
"list_tts_voices": {}
}
}list_tts_voices is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
List available TTS voices for different providers. Args: provider: Optional provider name ('openai' or 'kokoro'). If not specified, lists all available voices. Returns: A formatted list of available voices by provider. It is categorised as a Read tool in the Voice Mode MCP Server, which means it retrieves data without modifying state.
Register the Voice Mode MCP server in PolicyLayer and add a rule for list_tts_voices: 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 Voice Mode. Nothing to install.
list_tts_voices 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 list_tts_voices 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 list_tts_voices. 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.
list_tts_voices is provided by the Voice Mode MCP server (mbailey/voicemode). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Voice Mode, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
25 Voice Mode tools catalogued and risk-classified — across an index of 43,000+ MCP servers.