add · MCP from Scratch Server MCP: Risk & Policy

WHAT IT DOES

What add does on MCP from Scratch Server

AI agents call add to retrieve information from MCP from Scratch Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

THE RISK

Low Risk

Why add needs a policy

This tool performs a pure arithmetic calculation with no side effects, no data modification, and no external interactions. It simply computes and returns a value, making it a Read/query-style operation with minimal risk.

From the tool's definition Adds two numbers and returns the sum

Documented attack patterns abuse exactly the kind of access add gives an agent:

POLICY

How to control add

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP from Scratch Server, and nothing reaches the server without passing your rules. This is the rule we recommend for add:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "add": {}
  }
}

add is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register MCP from Scratch Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP from Scratch Server tools

Execute route_support_ticket Classifies a support message via sampling/createMessage, then routes it using server-side Execute unstable Throws on purpose to demonstrate handler exceptions → isError. Write add_note Registers a new demo://note/N resource and notifies list_changed. Write publish_status Updates demo://status and notifies subscribers. Write register_extra_tool Adds the greet tool at runtime and notifies tools/list_changed. Read divide Divides a by b. Returns a tool error when b is zero. Read echo Returns its input Read get_time Returns the server clock as an ISO-8601 timestamp.

All 12 MCP from Scratch Server tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about add

What does the add tool do? +

Adds two numbers and returns the sum. It is categorised as a Read tool in the MCP from Scratch Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on add? +

Register the MCP from Scratch Server 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 MCP from Scratch Server. Nothing to install.

What risk level is add? +

add is a Read tool with low risk. Read-only tools are generally safe to allow by default.

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 MCP from Scratch Server MCP server (pguso/mcp-from-scratch). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP from Scratch Server tool call.

Start from MCP from Scratch Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →

Free to start. No card required.

12 MCP from Scratch Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.