List available voices for text-to-speech.
AI agents call gemini_list_voices_tool to retrieve information from MCP Gemini without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only retrieves and enumerates available voices, producing no side effects. It is a read-only operation that queries system state. The low severity reflects minimal risk even if misused by an AI agent, as listing voices cannot harm data or systems.
From the tool's definition Tool description states 'List available voices for text-to-speech' — this is a query/list operation that retrieves configuration data without modifying anything.
Attacks that exploit this kind of access
List available voices for text-to-speech. It is categorised as a Read tool in the MCP Gemini MCP Server, which means it retrieves data without modifying state.
Register the MCP Gemini MCP server in PolicyLayer and add a rule for gemini_list_voices_tool: 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 Gemini. Nothing to install.
gemini_list_voices_tool 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 gemini_list_voices_tool 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 gemini_list_voices_tool. 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.
gemini_list_voices_tool is provided by the MCP Gemini MCP server (mcp-gemini-crunchtools). 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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