generate_fill · Filopastry MCP: Risk & Policy

WHAT IT DOES

What generate_fill does on Filopastry

AI agents use generate_fill 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 generate_fill needs a policy

This tool generates/creates a drum fill pattern, which is a Write operation (creating new data/content). It has no destructive, financial, or shell-execution implications. The blast radius is low since it only produces a music pattern output.

From the tool's definition Generate drum fill — creates a new drum fill pattern in the Strudel.cc live coding environment

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

generate_fill Rate-limited

generate_fill 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": {
    "generate_fill": {
      "limits": [
        {
          "counter": "generate_fill_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 generate_fill

What does the generate_fill tool do? +

Generate drum fill. 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 generate_fill? +

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

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

Can I rate-limit generate_fill? +

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

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

generate_fill 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.