apply_mix_balance · Orpheus MCP: Risk & Policy

WHAT IT DOES

What apply_mix_balance does on Orpheus

AI agents use apply_mix_balance 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 apply_mix_balance needs a policy

This tool creates or modifies mix parameters in an audio project. It adjusts fader levels (mix balance), which are reversible changes to audio track configuration. While it affects the sound output, faders can be undone or reset, making it a Write operation rather than Execute (which would imply code/script execution with unpredictable side effects) or Destructive (which implies irreversible data loss).

From the tool's definition Tool modifies audio fader levels in REAPER (fader_db values), which is a reversible parameter adjustment (audio mix balancing). The calculation shows it computes and applies new fader positions based on genre/role targets and effect chain offsets.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

apply_mix_balance Rate-limited

apply_mix_balance 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": {
    "apply_mix_balance": {
      "limits": [
        {
          "counter": "apply_mix_balance_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 apply_mix_balance

What does the apply_mix_balance tool do? +

fader_db = mix_target(genre, role) − chain_offset(track FX), clamped to fader range. 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 apply_mix_balance? +

Register the Orpheus MCP server in PolicyLayer and add a rule for apply_mix_balance: 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 apply_mix_balance? +

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

Can I rate-limit apply_mix_balance? +

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

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

apply_mix_balance 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.