virtuoso_execute_skill · Virtuoso Schematic MCP

WHAT IT DOES

What virtuoso_execute_skill does on Virtuoso Schematic MCP

AI agents invoke virtuoso_execute_skill to trigger actions in Virtuoso Schematic MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why virtuoso_execute_skill needs a policy

This tool directly executes arbitrary code in a live Virtuoso environment, which can trigger external operations, modify design state, query databases, or execute shell commands depending on what SKILL expressions are passed to it.

From the tool's definition "Execute an arbitrary SKILL expression in the Virtuoso environment" — the tool explicitly allows execution of arbitrary code (SKILL is Cadence's programming language for Virtuoso) with no restrictions on what expressions can be run.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

virtuoso_execute_skill Rate-limited

virtuoso_execute_skill stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "virtuoso_execute_skill": {
      "limits": [
        {
          "counter": "virtuoso_execute_skill_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Virtuoso Schematic MCP, so you can run agents against it safely.

FAQ

Questions about virtuoso_execute_skill

What does the virtuoso_execute_skill tool do? +

Execute an arbitrary SKILL expression in the Virtuoso environment. It is categorised as a Execute tool in the Virtuoso Schematic MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on virtuoso_execute_skill? +

Register the Virtuoso Schematic MCP server in PolicyLayer and add a rule for virtuoso_execute_skill: 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 Virtuoso Schematic MCP. Nothing to install.

What risk level is virtuoso_execute_skill? +

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

Can I rate-limit virtuoso_execute_skill? +

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

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

virtuoso_execute_skill is provided by the Virtuoso Schematic MCP server (michelebergo/virtuoso-schematic-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.