Isitdisposable MCP Server

isitdisposable-mcp

A Model Context Protocol (MCP) server that lets an AI agent check whether an email address or domain is disposable, using the isitdisposable.com application programming interface (API).

Installation

The server is published to the npm registry and is normally run with npx, so there is nothing to install by hand; the examples below show how to wire it into a Model Context Protocol (MCP) host.

Claude Desktop

Add this to your Claude Desktop configuration:

{
  "mcpServers": {
    "isitdisposable": {
      "command": "npx",
      "args": ["-y", "isitdisposable-mcp"],
      "env": { "ISITDISPOSABLE_API_KEY": "your_secret_key" }
    }
  }
}

Claude Code

claude mcp add isitdisposable --env ISITDISPOSABLE_API_KEY=your_secret_key -- npx -y isitdisposable-mcp

Getting an API key

An isitdisposable.com key is required. Get a free key at https://isitdisposable.com (a free tier is available), then set it as ISITDISPOSABLE_API_KEY in the configuration above.

Tools

Every tool returns the same verdict shape. disposable is the core true or false verdict: a disposable address is a throwaway or temporary inbox used to receive a single signup message and evade normal registration requirements, rather than a real, ongoing mailbox. action is the recommended handling of allow, warn, or block. A handful of opt in signals may also be present, including mx_valid (whether the domain's mail servers accept mail), relay (a forwarding or catch all style address), public_domain (a well known free provider such as Gmail), and did_you_mean (a likely intended domain when the one given looks like a typo).

Fail open behavior

This server always fails open. If a network problem, a timeout, a rate limit, or a server error prevents a real check from completing, the tool call still succeeds (it never throws or crashes the connection). It retries once after a short delay, and if that also fails, it returns a result with checked: false, disposable: null, and action: "allow", along with a note explaining that the check could not be completed. An agent using this tool should treat that outcome as inconclusive, not as a signal that the address is safe.

If no API key is configured, the server still starts normally and responds to the Model Context Protocol (MCP) handshake; each tool call then returns an error result pointing to https://isitdisposable.com to get a free key.

Publishing (manual)

cd ~/Code/active/isid-mcp
npm install
npm run build
npm test
npm login
npm publish

server.json is currently written against the 2025-12-11 registry schema. The registry schema can drift again, so before a future registry submission, validate server.json against the exact schema URL named in its own $schema field, or upgrade mcp-publisher to the latest release and run its validate command (older releases, including the one this file was first written with, lack that command and generate an outdated template).