create_conversation_message

THE RISK

Medium Risk

Why create_conversation_message needs a policy

This tool creates new messages within conversations, which is a reversible write operation. It does not execute code or trigger external side effects beyond message creation, does not delete data (Destructive), and does not move money (Financial).

From the tool's definition Tool description states 'Sends a message to an existing conversation', which is a create/write operation that modifies conversation state by adding new message content.

Documented attack patterns abuse exactly the kind of access create_conversation_message gives an agent:

POLICY

How to control create_conversation_message

PolicyLayer is an MCP gateway — it sits between your AI agents and Carbon Voice, and nothing reaches the server without passing your rules. This is the rule we recommend for create_conversation_message:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_conversation_message": {
      "limits": [
        {
          "counter": "create_conversation_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

create_conversation_message stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Carbon Voice — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Carbon Voice tools

Destructive delete_folder Delete a folder by its ID. Deleting a folder will also delete nested folders and all the m Execute run_ai_action Run an AI Action (Prompt) for a message. You can run an AI Action for a message by its ID Execute run_ai_action_for_shared_link Run an AI Action (Prompt) for a shared link. You can run an AI Action for a shared link by Write add_attachments_to_message Add attachments to a message. In order to add attachments to a message, you must provide a Write create_direct_message Send a Direct Message (DM) to a User or a Group of Users. Write create_folder Create a new folder. Write create_voicememo_message Create a VoiceMemo Message. In order to create a VoiceMemo Message, you must provide a tra Write move_folder Move a folder by its ID. Move a Folder into another Folder or into a Workspace.

All 28 Carbon Voice tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about create_conversation_message

What does the create_conversation_message tool do? +

Sends a message to an existing conversation or any type with a conversation_id. It is categorised as a Write tool in the Carbon Voice MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_conversation_message? +

Register the Carbon Voice MCP server in PolicyLayer and add a rule for create_conversation_message: 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 Carbon Voice. Nothing to install.

What risk level is create_conversation_message? +

create_conversation_message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_conversation_message? +

Yes. Add a rate_limit block to the create_conversation_message 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.

How do I block create_conversation_message completely? +

Set action: deny in the PolicyLayer policy for create_conversation_message. 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.

What MCP server provides create_conversation_message? +

create_conversation_message is provided by the Carbon Voice MCP server (phononx/cv-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Carbon Voice tool call.

Start from Carbon Voice, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →