calculate · MCP Demo Application MCP: Risk & Policy

WHAT IT DOES

What calculate does on MCP Demo Application

AI agents invoke calculate to trigger actions in MCP Demo Application. 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

This tool evaluates mathematical expressions, which constitutes executing computation. While limited to basic arithmetic, expression evaluators can sometimes be exploited for injection or unintended computation if input validation is weak. The blast radius is moderate — it's unlikely to affect external systems but could be misused for resource exhaustion or unexpected behavior if the parser is not sandboxed.

From the tool's definition "Perform mathematical calculations" with support for "basic arithmetic operations (+, -, *, /) and parentheses"

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 MCP Demo Application, so you can run agents against it safely.

FAQ

Questions about calculate

What does the calculate tool do? +

Perform mathematical calculations. Supports basic arithmetic operations (+, -, *, /) and parentheses. It is categorised as a Execute tool in the MCP Demo Application 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 MCP Demo Application 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 MCP Demo Application. 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 MCP Demo Application MCP server (mic-havock/model-context-protocol). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.