reharmonize · Music21 Composer MCP: Risk & Policy

WHAT IT DOES

What reharmonize does on Music21 Composer MCP

AI agents use reharmonize 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 reharmonize needs a policy

Reharmonization modifies musical composition data by altering harmonic structures. This is a Write operation because it creates or modifies data reversibly—reharmonized chord progressions can be undone or changed again. It does not execute external code, delete data irreversibly, or move money.

From the tool's definition Tool name 'reharmonize' combined with server description indicating 'chord reharmonization' capability; creates modified musical data (reharmonized chords) that is reversible and non-destructive.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

reharmonize Rate-limited

reharmonize 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": {
    "reharmonize": {
      "limits": [
        {
          "counter": "reharmonize_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 reharmonize

What does the reharmonize tool do? +

reharmonize. 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 reharmonize? +

Register the Music21 Composer MCP server in PolicyLayer and add a rule for reharmonize: 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 reharmonize? +

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

Can I rate-limit reharmonize? +

Yes. Add a rate_limit block to the reharmonize 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 reharmonize completely? +

Set action: deny in the PolicyLayer policy for reharmonize. 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 reharmonize? +

reharmonize 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.