set_time_signature · Orpheus MCP: Risk & Policy

WHAT IT DOES

What set_time_signature does on Orpheus

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

WHY IT NEEDS A POLICY

Why set_time_signature needs a policy

Time signature changes are reversible edits to a REAPER project structure. This is a Write operation (modifies data) rather than Destructive (cannot be undone), Execute (runs arbitrary code), or Read-only. Severity is medium because incorrect time signatures could corrupt a musical composition's structure, but the change is undoable.

From the tool's definition Tool name 'set_time_signature' indicates it modifies a project parameter (time signature) in REAPER. No description provided, but context from sibling tools (apply_changes, apply_mix_balance, build_project_spec) suggests this tool creates or modifies project…

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_time_signature Rate-limited

set_time_signature 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": {
    "set_time_signature": {
      "limits": [
        {
          "counter": "set_time_signature_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 Orpheus, so you can run agents against it safely.

FAQ

Questions about set_time_signature

What does the set_time_signature tool do? +

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

How do I enforce a policy on set_time_signature? +

Register the Orpheus MCP server in PolicyLayer and add a rule for set_time_signature: 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 Orpheus. Nothing to install.

What risk level is set_time_signature? +

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

Can I rate-limit set_time_signature? +

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

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

set_time_signature is provided by the Orpheus MCP server (mal0ware/orpheus). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.