send_message · Synthlab MCP: Risk & Policy

WHAT IT DOES

What send_message does on Synthlab

AI agents invoke send_message to trigger actions in Synthlab. 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.

WHY IT NEEDS A POLICY

Why send_message needs a policy

This tool triggers external operations by sending control messages to a live Pure Data instance. It can influence a running audio synthesis process in real-time via network protocols (OSC/UDP or FUDI/TCP), making it an Execute-category tool. Misuse could disrupt live audio systems, trigger unintended synthesis behaviors, or interact with connected hardware/software in unpredictable ways, warranting high severity.

From the tool's definition Send a control message to a running Pure Data instance via OSC (UDP) or FUDI (TCP)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

send_message Rate-limited

send_message 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "send_message": {
      "limits": [
        {
          "counter": "send_message_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Synthlab, so you can run agents against it safely.

FAQ

Questions about send_message

What does the send_message tool do? +

Send a control message to a running Pure Data instance via OSC (UDP) or FUDI (TCP). It is categorised as a Execute tool in the Synthlab MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on send_message? +

Register the Synthlab MCP server in PolicyLayer and add a rule for send_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 Synthlab. Nothing to install.

What risk level is send_message? +

send_message is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit send_message? +

Yes. Add a rate_limit block to the send_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 send_message completely? +

Set action: deny in the PolicyLayer policy for send_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 send_message? +

send_message is provided by the Synthlab MCP server (j0kz/synthlab-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.