AI agents invoke transport_record to trigger actions in ReaperMCP. 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.
This tool executes a command that initiates audio recording in a DAW. While not destructive by itself, it performs an irreversible action in real-time (audio capture begins and cannot be undone without manual intervention). An AI agent calling this without user consent could waste time, record unwanted audio, or interfere with a user's active session.
From the tool's definition Tool description states 'Start recording' - this initiates an external operation (recording audio in REAPER) whose effects depend on runtime state and user intent.
Documented attack patterns abuse exactly the kind of access transport_record gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ReaperMCP, and nothing reaches the server without passing your rules. This is the rule we recommend for transport_record:
{
"version": "1",
"default": "deny",
"tools": {
"transport_record": {
"limits": [
{
"counter": "transport_record_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}transport_record 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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Start recording. It is categorised as a Execute tool in the ReaperMCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Reaper MCP server in PolicyLayer and add a rule for transport_record: 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 ReaperMCP. Nothing to install.
transport_record 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 transport_record 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 transport_record. 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.
transport_record is provided by the Reaper MCP server (xdarkzx/reaper-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from ReaperMCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
138 ReaperMCP tools catalogued and risk-classified — across an index of 43,000+ MCP servers.