add_coupler · Funky Junction MCP: Risk & Policy

WHAT IT DOES

What add_coupler does on Funky Junction

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

WHY IT NEEDS A POLICY

Why add_coupler needs a policy

This tool creates or modifies a quantum circuit design by adding a coupler element between two qubits. This is a reversible design operation (components can be removed or modified) with no side effects beyond the local circuit model. It does not execute simulations, delete data, or trigger external operations—it merely updates the circuit design state.

From the tool's definition add_coupler: Add a square spiral coupler between Q1 and Q2. The verb 'Add' indicates creation of a new design component within the quantum circuit.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_coupler Rate-limited

add_coupler 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_coupler": {
      "limits": [
        {
          "counter": "add_coupler_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 Funky Junction, so you can run agents against it safely.

FAQ

Questions about add_coupler

What does the add_coupler tool do? +

Add a square spiral coupler between Q1 and Q2. It is categorised as a Write tool in the Funky Junction 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_coupler? +

Register the Funky Junction MCP server in PolicyLayer and add a rule for add_coupler: 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 Funky Junction. Nothing to install.

What risk level is add_coupler? +

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

Can I rate-limit add_coupler? +

Yes. Add a rate_limit block to the add_coupler 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_coupler completely? +

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

add_coupler is provided by the Funky Junction MCP server (paulgoldschmidt/qsim-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.