Set the automation mode for a track.
AI agents use set_track_automation_mode 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 settings (automation mode) but does not irreversibly delete data or execute arbitrary code. It fits the Write category as it creates or modifies data reversibly. Severity is medium because misuse could alter the mix/master session state in ways that might disrupt a production workflow, but changes are undo-able and do not cause financial impact or permanent data loss.
From the tool's definition The tool description states it 'Set[s] the automation mode for a track,' which modifies track automation settings in REAPER DAW. This is a configuration change that persists but is reversible (automation modes can be changed back to previous states).
Documented attack patterns abuse exactly the kind of access set_track_automation_mode 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_automation_mode:
{
"version": "1",
"default": "deny",
"tools": {
"set_track_automation_mode": {
"limits": [
{
"counter": "set_track_automation_mode_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_track_automation_mode 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.
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Set the automation mode 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_automation_mode: 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_automation_mode 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_automation_mode 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_automation_mode. 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_automation_mode 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.
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158 Reaper tools catalogued and risk-classified — across an index of 43,000+ MCP servers.