compose_patch · Synthlab MCP: Risk & Policy

WHAT IT DOES

What compose_patch does on Synthlab

AI agents use compose_patch to create or update resources in Synthlab — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Synthlab environment.

WHY IT NEEDS A POLICY

Why compose_patch needs a policy

The tool creates new data (a Pure Data patch) based on user input, which is reversible—patches can be edited or deleted. It does not execute the patch, delete data, or move money. However, the severity is medium rather than low because synthesized music patches could potentially include controller mappings or automation that, if deployed without review, might trigger unintended audio/hardware effects.

From the tool's definition Tool 'compose_patch' description states it will 'Compose a complete musical Pd patch' — creating a new artifact (Pd patch file) that did not exist before. This is a creation/write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

compose_patch Rate-limited

compose_patch 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.

View as policy code

policy.json

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

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 compose_patch

What does the compose_patch tool do? +

Compose a complete musical Pd patch from a high-level song description. It is categorised as a Write tool in the Synthlab MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on compose_patch? +

Register the Synthlab MCP server in PolicyLayer and add a rule for compose_patch: 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 compose_patch? +

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

Can I rate-limit compose_patch? +

Yes. Add a rate_limit block to the compose_patch 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 compose_patch completely? +

Set action: deny in the PolicyLayer policy for compose_patch. 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 compose_patch? +

compose_patch 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.