Create an empty MIDI item on a track. Returns the item's global index.
AI agents use item_create_midi to create or update resources in ReaperMCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your ReaperMCP environment.
This tool creates a new MIDI item, which is a reversible modification to the project state. It does not execute code or shell commands, does not permanently delete data, and does not involve financial transactions. The action is typical Write behavior: creating a new data element that can be undone (via undo in REAPER or deletion).
From the tool's definition Tool name 'item_create_midi' and description 'Create an empty MIDI item on a track' explicitly indicate creation of new data structure (MIDI item) within the music production project.
Documented attack patterns abuse exactly the kind of access item_create_midi 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 item_create_midi:
{
"version": "1",
"default": "deny",
"tools": {
"item_create_midi": {
"limits": [
{
"counter": "item_create_midi_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}item_create_midi 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.
Create an empty MIDI item on a track. Returns the item's global index. It is categorised as a Write tool in the ReaperMCP 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 item_create_midi: 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.
item_create_midi 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 item_create_midi 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 item_create_midi. 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.
item_create_midi 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.