apply_scale · Filopastry MCP: Risk & Policy

WHAT IT DOES

What apply_scale does on Filopastry

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

WHY IT NEEDS A POLICY

Why apply_scale needs a policy

The tool creates or modifies music data (notes) in a reversible manner by applying scale transformations. This is a typical Write operation in the music domain - it transforms existing patterns through algorithmic means but the changes are non-destructive and reversible (scales can be removed, changed, or patterns regenerated).

From the tool's definition Tool name 'apply_scale' and description 'Apply scale to notes' indicate the tool modifies musical note data by applying a scale transformation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

apply_scale Rate-limited

apply_scale 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_scale": {
      "limits": [
        {
          "counter": "apply_scale_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 Filopastry, so you can run agents against it safely.

FAQ

Questions about apply_scale

What does the apply_scale tool do? +

Apply scale to notes. It is categorised as a Write tool in the Filopastry 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_scale? +

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

What risk level is apply_scale? +

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

Can I rate-limit apply_scale? +

Yes. Add a rate_limit block to the apply_scale 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_scale completely? +

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

apply_scale is provided by the Filopastry MCP server (youwenshao/filopastry). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.