Set the record input for a track.
AI agents use set_track_input 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.
This tool modifies track configuration (input routing/assignment) which is reversible and does not execute arbitrary code or trigger permanent destructive actions. It changes audio routing state, which qualifies as a Write operation. Severity is medium because misconfiguration could affect recording workflows and audio paths, but the change is easily reversible.
From the tool's definition Tool name 'set_track_input' and description 'Set the record input for a track' indicate modification of track configuration settings in REAPER DAW.
Documented attack patterns abuse exactly the kind of access set_track_input gives an agent:
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_input:
{
"version": "1",
"default": "deny",
"tools": {
"set_track_input": {
"limits": [
{
"counter": "set_track_input_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_track_input 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.
Free to start. No card required.
Set the record input for a track. 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.
Register the Reaper MCP server in PolicyLayer and add a rule for set_track_input: 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.
set_track_input is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the set_track_input 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 set_track_input. 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.
set_track_input 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.
Start from Reaper, 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.
158 Reaper tools catalogued and risk-classified — across an index of 43,000+ MCP servers.