calculate · Custom MCP Server MCP: Risk & Policy

WHAT IT DOES

What calculate does on Custom MCP Server

AI agents invoke calculate to trigger actions in Custom MCP Server. 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

Executing mathematical expressions falls under the Execute category since it runs a computation based on user-supplied input. The 'safely' qualifier and 'basic' scope suggest limited blast radius — arbitrary code execution is unlikely — but the tool evaluates dynamic input rather than merely reading static data.

From the tool's definition 'Perform basic mathematical calculations safely' — the word 'perform' and 'calculations' imply execution of expressions; 'safely' suggests sandboxed evaluation but still involves running computational logic

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 Custom MCP Server, so you can run agents against it safely.

FAQ

Questions about calculate

What does the calculate tool do? +

Perform basic mathematical calculations safely. It is categorised as a Execute tool in the Custom MCP Server 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 Custom MCP Server 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 Custom MCP Server. 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 Custom MCP Server MCP server (meerisha/custom-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.