stretch · Filopastry MCP: Risk & Policy

WHAT IT DOES

What stretch does on Filopastry

AI agents use stretch 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 stretch needs a policy

The tool modifies an existing pattern by stretching it in time, which is a reversible transformation of music pattern data. No code execution, deletion, or financial implications. It creates a modified version of a pattern within the Strudel.cc environment.

From the tool's definition 'Time stretch pattern' — modifies a music pattern's timing/tempo

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

stretch Rate-limited

stretch 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": {
    "stretch": {
      "limits": [
        {
          "counter": "stretch_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 stretch

What does the stretch tool do? +

Time stretch 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 stretch? +

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

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

Can I rate-limit stretch? +

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

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

stretch 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.