Medium Risk

set_track_master_send

set_track_master_send

How to control set_track_master_send ↓

What set_track_master_send does on Reaper

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

Medium Risk

Why set_track_master_send needs a policy

Based on the name, this tool likely configures whether a track sends its audio to the master bus in REAPER DAW. This is a reversible settings change (Write), but the empty description lowers confidence. It does not appear to delete data or execute code, so Write is the most appropriate category given the naming convention.

From the tool's definition Tool name: set_track_master_send — description is empty and uninformative

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

How to control set_track_master_send

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

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_track_master_send": {
      "limits": [
        {
          "counter": "set_track_master_send_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

set_track_master_send 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.

  1. Create a free account and register Reaper — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

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Related tools and policies

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Questions about set_track_master_send

What does the set_track_master_send tool do? +

set_track_master_send. It is categorised as a Write tool in the Reaper MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_track_master_send? +

Register the Reaper MCP server in PolicyLayer and add a rule for set_track_master_send: 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 Reaper. Nothing to install.

What risk level is set_track_master_send? +

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

Can I rate-limit set_track_master_send? +

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

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

set_track_master_send is provided by the Reaper MCP server (twelvetake-studios/reaper-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Reaper tool call.

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

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