add_effect · Filopastry MCP: Risk & Policy

WHAT IT DOES

What add_effect does on Filopastry

AI agents use add_effect 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 add_effect needs a policy

This tool modifies an existing music pattern by adding an effect to it. This is a reversible write/modification operation within the Strudel.cc live coding environment. No code execution, deletion, or financial action is involved. Blast radius is low as it only affects in-session music patterns.

From the tool's definition 'Add effect to pattern' — modifies a pattern by adding an audio effect

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_effect Rate-limited

add_effect 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": {
    "add_effect": {
      "limits": [
        {
          "counter": "add_effect_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 add_effect

What does the add_effect tool do? +

Add effect to pattern. 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 add_effect? +

Register the Filopastry MCP server in PolicyLayer and add a rule for add_effect: 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 add_effect? +

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

Can I rate-limit add_effect? +

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

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

add_effect 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.