calculate · Demo MCP: Risk & Policy

WHAT IT DOES

What calculate does on Demo

AI agents invoke calculate to trigger actions in Demo. 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 calculate needs a policy

Evaluating math expressions can range from safe arithmetic to arbitrary code execution (e.g., via eval()). The description is minimal and does not specify sandboxing. Given the context of a demo server with simple tools (add, get_weather, greet), it is likely a basic calculator, but the risk of unsandboxed expression evaluation warrants Execute classification at medium severity.

From the tool's definition '计算数学表达式' (calculate math expression) — evaluates an expression, which depending on implementation could execute arbitrary code

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

calculate Rate-limited

calculate 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": {
    "calculate": {
      "limits": [
        {
          "counter": "calculate_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 Demo, so you can run agents against it safely.

FAQ

Questions about calculate

What does the calculate tool do? +

计算数学表达式。. It is categorised as a Execute tool in the Demo MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on calculate? +

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

What risk level is calculate? +

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

Can I rate-limit calculate? +

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

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

calculate is provided by the Demo MCP server (liuyuyan6100/mcp-server-demo). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.