add_trace · Kicad MCP: Risk & Policy

WHAT IT DOES

What add_trace does on Kicad

AI agents use add_trace 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_trace needs a policy

This tool creates new PCB trace segments, which is a write operation that modifies the electronic design. While traces are fundamental to PCB layout, they can be undone or modified, making this a Write rather than Destructive category. The severity is medium because an AI agent adding incorrect traces could create electrical problems, short circuits, or design defects, but these can be corrected before manufacturing.

From the tool's definition Tool name 'add_trace' and description 'Add a trace segment between two points' indicate creation of PCB trace routing, which modifies the PCB design document.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_trace Rate-limited

add_trace 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_trace": {
      "limits": [
        {
          "counter": "add_trace_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_trace

What does the add_trace tool do? +

Add a trace segment between two points. 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_trace? +

Register the Kicad MCP server in PolicyLayer and add a rule for add_trace: 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_trace? +

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

Can I rate-limit add_trace? +

Yes. Add a rate_limit block to the add_trace 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_trace completely? +

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

add_trace 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.