set_design_variables · Funky Junction MCP: Risk & Policy

WHAT IT DOES

What set_design_variables does on Funky Junction

AI agents use set_design_variables 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 set_design_variables needs a policy

This tool modifies design state (design variables) in a reversible manner. It does not execute simulations, delete data, or trigger external operations—it only updates configuration parameters. Categorized as Write rather than Execute because parameter setting is distinct from running computations.

From the tool's definition Tool name 'set_design_variables' and description 'Set basic design variables like CPW width and gap' indicate modification of design parameters. CPW (coplanar waveguide) width and gap are fundamental configuration properties in quantum circuit design.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_design_variables Rate-limited

set_design_variables 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": {
    "set_design_variables": {
      "limits": [
        {
          "counter": "set_design_variables_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 set_design_variables

What does the set_design_variables tool do? +

Set basic design variables like CPW width and gap. 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 set_design_variables? +

Register the Funky Junction MCP server in PolicyLayer and add a rule for set_design_variables: 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 set_design_variables? +

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

Can I rate-limit set_design_variables? +

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

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

set_design_variables 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.