export_midi · Music21 Composer MCP: Risk & Policy

WHAT IT DOES

What export_midi does on Music21 Composer MCP

AI agents use export_midi to create or update resources in Music21 Composer MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Music21 Composer MCP environment.

WHY IT NEEDS A POLICY

Why export_midi needs a policy

MIDI export creates new files on the user's system, constituting irreversible data creation. While not destructive (data isn't deleted), it modifies the file system state.

From the tool's definition Tool name 'export_midi' indicates file creation/writing of MIDI format audio data. Server description confirms 'MIDI export' as a core capability. Empty description limits specificity but context is clear.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

export_midi Rate-limited

export_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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "export_midi": {
      "limits": [
        {
          "counter": "export_midi_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Music21 Composer MCP, so you can run agents against it safely.

FAQ

Questions about export_midi

What does the export_midi tool do? +

export_midi. It is categorised as a Write tool in the Music21 Composer MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on export_midi? +

Register the Music21 Composer MCP server in PolicyLayer and add a rule for export_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 Music21 Composer MCP. Nothing to install.

What risk level is export_midi? +

export_midi is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit export_midi? +

Yes. Add a rate_limit block to the export_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.

How do I block export_midi completely? +

Set action: deny in the PolicyLayer policy for export_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.

What MCP server provides export_midi? +

export_midi is provided by the Music21 Composer MCP server (viktorkelemen/music21-composer-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.