Save the current FX settings as a preset.
AI agents use save_fx_preset 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 creates or stores FX preset configurations in REAPER, which is a reversible write operation. It does not execute arbitrary code, delete data, or move financial resources. The blast radius is minimal—a mistaken preset save can be easily overwritten or deleted. Confidence is high because the intent is unambiguous from both name and description.
From the tool's definition Tool name 'save_fx_preset' and description 'Save the current FX settings as a preset' indicate creation/storage of configuration data.
Documented attack patterns abuse exactly the kind of access save_fx_preset 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 save_fx_preset:
{
"version": "1",
"default": "deny",
"tools": {
"save_fx_preset": {
"limits": [
{
"counter": "save_fx_preset_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}save_fx_preset 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.
Save the current FX settings as a preset. 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 save_fx_preset: 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.
save_fx_preset 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 save_fx_preset 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 save_fx_preset. 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.
save_fx_preset 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.