How do I install Mxprobe?

Mxprobe is a local plugin. Install it using npm package: mxprobe and add the generated configuration snippet to your AI app's MCP config file. Then restart your AI app.

Is Mxprobe safe to use?

Yes. Mxprobe passed MCP Marketplace's automated security scan with a score of 9.7/10 (low risk). Every server on MCP Marketplace is security-scanned before it's listed; see the full security report on this page for the findings and permissions.

What credentials does Mxprobe need?

Mxprobe requires the following credentials or environment variables: MXPROBE_API_KEY. You can find setup instructions on the server detail page.

What AI apps work with Mxprobe?

Mxprobe uses the Model Context Protocol (MCP) and works with any MCP-compatible AI app, including Claude, ChatGPT / Codex, Gemini, Copilot, Cursor, and more.

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Mxprobe MCP Server

by andrewchmr

Developer ToolsLow Risk9.7Local

Free

Email verification for AI agents: send, hold or kill with the reason. Signup and credits by API.

About

Email verification for AI agents: send, hold or kill with the reason. Signup and credits by API.

Security Report

9.7

Low Risk9.7Low Risk

Valid MCP server (3 strong, 3 medium validity signals). No known CVEs in dependencies. ⚠️ Package registry links to a different repository than scanned source. Imported from the Official MCP Registry. 1 finding(s) downgraded by scanner intelligence.

10 files analyzed · 1 issue found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

file_system

Check that this permission is expected for this type of plugin.

env_vars

Check that this permission is expected for this type of plugin.

What You'll Need

Set these up before or after installing:

Hosted-tier API key from POST /v1/signup or the signup tool. Without it the verify tools run the free local DNS tier.Required

Environment variable: MXPROBE_API_KEY

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "dev-mxprobe-mxprobe": {
      "env": {
        "MXPROBE_API_KEY": "your-mxprobe-api-key-here"
      },
      "args": [
        "-y",
        "mxprobe"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

MX Probe

Email verification for AI agents. One call returns send, hold or kill for an address, with the reason. Signup and credits happen by API too, so an outreach agent can provision itself. No form, no CAPTCHA, no dashboard.

Site and docs: https://mxprobe.dev
API: https://api.mxprobe.dev (it describes itself on GET /). OpenAPI: https://mxprobe.dev/openapi.json. For agents: https://mxprobe.dev/llms.txt
npm: mxprobe (CLI + MCP server), mxprobe-core (the engine)

npx mxprobe check hello@example.com          # free DNS tier, local, no key
npx mxprobe check --hosted hello@example.com # survivors go to the hosted SMTP probe
claude mcp add mxprobe -- npx -y mxprobe mcp # the MCP server

One click: Cursor · VS Code · LM Studio. In Claude Code the same server also comes as a plugin: /plugin marketplace add andrewchmr/mxprobe, then /plugin install mxprobe@mxprobe.

{
  "email": "hello@example.com",
  "action": "send",
  "verdict": "OK",
  "reason": "mailbox accepted by aspmx.l.google.com",
  "checks": { "syntax": true, "mx": "aspmx.l.google.com", "smtp": "accepted", "catch_all": false }
}

action is send, hold or kill; verdict is OK, WEAK or DEAD. A hold never becomes a kill on a refusal, a greylist or a catch-all. Only a 5xx that names the mailbox kills.

Layout

Path	What
`packages/core`	The engine: DNS tier, SMTP probe, the verdict contract and the API's wire types. Zero dependencies.
`packages/cli`	`npx mxprobe check
`server`	The hosted API: `node:http` + `node:sqlite`, Stripe Checkout, Resend, Telegram.
`site`	The landing page, static.
`deploy`	Caddyfile, systemd units, the install script and the runbook.

Develop

Everything is TypeScript (strict, ESM). Each package compiles its src/ to dist/ with tsc -b; the published packages ship dist/ only. mxprobe and the server import mxprobe-core through the workspace link to its dist/, so pnpm build at the root (which runs the packages in dependency order) must come before a single package's test or typecheck. Tests are .ts files that Node runs directly with its built-in type stripping.

pnpm install
pnpm build                      # tsc -b in each package, core first
pnpm test                       # builds, then: fake resolver, fake SMTP server, in-memory SQLite. No network.
pnpm typecheck                  # the sources and the tests, without emitting
pnpm test:live                  # the DNS tier against the real network
pnpm check a@b.com              # the CLI from this checkout
cp server/.env.example server/.env && pnpm dev:server

Node 22.18 or newer (24 recommended) to develop and to run the tests; the compiled engine and CLI run on Node 20, the server on 22.13 or newer (node:sqlite).

Pricing

100 checks free at signup, then 9 USD per 10,000, one payment, credits never expire. Addresses are logged for 24 hours for debugging and then deleted.

MIT.