AI agents invoke send_note_off to trigger actions in MCP MIDI Server. 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 an external operation by sending a MIDI Note Off message to a virtual MIDI port, which can affect any connected MIDI-receiving software or hardware. It is not a simple read, nor does it destroy data or involve finances. The blast radius is low since MIDI messages are transient audio/music control signals with no persistent state damage.
From the tool's definition 'Sends a MIDI Note Off message' — triggers an external MIDI operation that affects connected software/hardware.
Documented attack patterns abuse exactly the kind of access send_note_off gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP MIDI Server, and nothing reaches the server without passing your rules. This is the rule we recommend for send_note_off:
{
"version": "1",
"default": "deny",
"tools": {
"send_note_off": {
"limits": [
{
"counter": "send_note_off_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}send_note_off 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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Sends a MIDI Note Off message. It is categorised as a Execute tool in the MCP MIDI Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the MCP MIDI Server MCP server in PolicyLayer and add a rule for send_note_off: 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 MCP MIDI Server. Nothing to install.
send_note_off 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 send_note_off 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 send_note_off. 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.
send_note_off is provided by the MCP MIDI Server MCP server (sandst1/mcp-server-midi). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP MIDI Server, 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.
4 MCP MIDI Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.