AI agents invoke narrate_conversation to trigger actions in Speech MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The tool appears to execute speech synthesis or narration logic to vocalize conversation content. While no description is provided (lowering confidence), the name and context among other speech/audio tools suggest it triggers external audio operations. This qualifies as Execute rather than Read because it performs an action with external effects (audio output generation).
From the tool's definition Tool name 'narrate_conversation' indicates execution of narration/speech synthesis; combined with sibling tools 'narrate', 'reply', 'start_conversation', and 'transcribe' that perform voice interaction operations.
Documented attack patterns abuse exactly the kind of access narrate_conversation gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Speech MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for narrate_conversation:
{
"version": "1",
"default": "deny",
"tools": {
"narrate_conversation": {
"limits": [
{
"counter": "narrate_conversation_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}narrate_conversation stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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narrate_conversation. It is categorised as a Execute tool in the Speech MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Speech MCP server in PolicyLayer and add a rule for narrate_conversation: 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 Speech MCP. Nothing to install.
narrate_conversation is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the narrate_conversation 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 narrate_conversation. 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.
narrate_conversation is provided by the Speech MCP server (kvadratni/speech-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Speech MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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7 Speech MCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.