add · Calculator MCP: Risk & Policy

WHAT IT DOES

What add does on Calculator MCP

AI agents use add to create or update resources in Calculator MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Calculator MCP environment.

WHY IT NEEDS A POLICY

Why add needs a policy

An AI agent can call add faster than any human can review — one bad instruction and it creates or modifies resources in Calculator MCP by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add Rate-limited

add stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "add": {
      "limits": [
        {
          "counter": "add_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about add

What does the add tool do? +

执行浮点数加法运算. It is categorised as a Write tool in the Calculator MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add? +

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

What risk level is add? +

add is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit add? +

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

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

add is provided by the Calculator MCP server (kelseyee/mcp_calculator). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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