High Risk →

evaluate_script

Run a kernelCAD .kcad.ts script and report pass/fail + feature count + diagnostics. Pass either { file: "<path>" } or { code: "<inline source>" }.

Risk signalsAccepts file system path (file) · Accepts freeform code/query input (code)

Part of the Kernelcad server.

evaluate_script can trigger actions in Kernelcad, with no limits today. PolicyLayer puts allow, deny, and rate-limit rules on every call. Live in minutes.

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Free to start. No card required.

AI agents invoke evaluate_script to trigger processes or run actions in Kernelcad. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.

evaluate_script can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.

Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "evaluate_script": {
      "limits": [
        {
          "counter": "evaluate_script_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

See the full Kernelcad policy for all 48 tools.

Get this rule live on your own Kernelcad server in minutes. PolicyLayer enforces it on every call, before it runs.

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View all 48 tools →

These attack patterns abuse exactly the kind of access evaluate_script gives an agent. Each links to the full case and the policy that stops it:

Browse the full MCP Attack Database →

Every attack above starts with a tool call. PolicyLayer checks each one against your policy first, so evaluate_script only ever does what you allow.

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Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.

What does the evaluate_script tool do? +

Run a kernelCAD .kcad.ts script and report pass/fail + feature count + diagnostics. Pass either { file: "<path>" } or { code: "<inline source>" }.. It is categorised as a Execute tool in the Kernelcad MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on evaluate_script? +

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

What risk level is evaluate_script? +

evaluate_script is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit evaluate_script? +

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

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

evaluate_script is provided by the Kernelcad MCP server (kernelcad). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Kernelcad tool call.

Deterministic rules across all 48 Kernelcad tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

4,600+ MCP servers and 31,000+ tools scanned and risk-classified.

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