add_copper_zone · Kicad MCP: Risk & Policy

WHAT IT DOES

What add_copper_zone does on Kicad

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

WHY IT NEEDS A POLICY

Why add_copper_zone needs a policy

Copper zones are PCB design elements that define conductive regions. Creating a copper zone modifies the PCB design reversibly but can have significant downstream effects on electrical connectivity, manufacturing, and circuit behavior if placed incorrectly. This is a Write operation (creates new design data) rather than Destructive (zones can be removed/edited).

From the tool's definition Tool name 'add_copper_zone' indicates creation of a copper zone on a PCB. Sibling tools on the same server (add_pcb_line, add_pcb_text, add_lib_symbol, add_label, etc.) are all write/create operations that modify design artifacts.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_copper_zone Rate-limited

add_copper_zone 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_copper_zone": {
      "limits": [
        {
          "counter": "add_copper_zone_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 Kicad, so you can run agents against it safely.

FAQ

Questions about add_copper_zone

What does the add_copper_zone tool do? +

add_copper_zone. It is categorised as a Write tool in the Kicad 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_copper_zone? +

Register the Kicad MCP server in PolicyLayer and add a rule for add_copper_zone: 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 Kicad. Nothing to install.

What risk level is add_copper_zone? +

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

Can I rate-limit add_copper_zone? +

Yes. Add a rate_limit block to the add_copper_zone 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_copper_zone completely? +

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

add_copper_zone is provided by the Kicad MCP server (productofamerica/mcp-server-kicad). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.