MCP Email Sender — Email Validation & SMTP for AI Agents

An MCP (Model Context Protocol) server that gives AI agents the ability to validate email addresses, check MX records, detect disposable/role-based emails, and send emails via SMTP — all with zero external dependencies.

Features

• 8 MCP Tools: validate_email, validate_email_batch, check_mx_records, is_disposable, is_role_based, send_email, send_email_batch, test_smtp_connection
• Zero dependencies — pure Python stdlib (smtplib, email, re, socket)
• Email validation — format check, disposable detection, role-based detection, MX record lookup
• Batch operations — validate or send multiple emails in one call
• SMTP support — TLS, SSL, plain, with CC/BCC/Reply-To
• STDIO JSON-RPC mode — drop-in for Claude Desktop, Hermes, or any MCP client
• Environment-based config — SMTP credentials from env vars or tool args

Quick Start

# STDIO mode (for MCP clients)
python -m src.server --stdio

# Print manifest
python -m src.server --manifest

Use as a library

from src.server import MCPEmailServer
import json

server = MCPEmailServer()

# Validate email
result = server.handle_tool_call("validate_email", {"email": "user@gmail.com"})
print(json.loads(result))  # {"valid_format": true, "overall_valid": true, ...}

# Batch validate
result = server.handle_tool_call("validate_email_batch", {
    "emails": ["user@gmail.com", "test@mailinator.com", "bad-email"]
})

# Send email
result = server.handle_tool_call("send_email", {
    "to": "recipient@example.com",
    "subject": "Hello from AI",
    "body": "This email was sent by an AI agent via MCP.",
    "smtp_host": "smtp.gmail.com",
    "smtp_port": 587,
    "smtp_username": "your@gmail.com",
    "smtp_password": "app-password",
    "use_tls": True
})

MCP Tool Reference

Tool	Description	Required Params
validate_email	Full validation (format, disposable, role, MX)	email
validate_email_batch	Batch validate multiple emails	emails
check_mx_records	MX records for a domain	domain
is_disposable	Check if disposable email service	email
is_role_based	Check if role-based (admin@, info@)	email
send_email	Send via SMTP	to, subject, body
send_email_batch	Send multiple emails	emails
test_smtp_connection	Test SMTP server connection	—

SMTP Configuration

Set via environment variables or pass in tool args:

export SMTP_HOST=smtp.gmail.com
export SMTP_PORT=587
export SMTP_USERNAME=your@gmail.com
export SMTP_PASSWORD=your-app-password
export SMTP_TLS=true

Integration with Claude Desktop

{
  "mcpServers": {
    "email-sender": {
      "command": "python",
      "args": ["-m", "src.server", "--stdio"],
      "cwd": "/path/to/mcp-email-sender",
      "env": {
        "SMTP_HOST": "smtp.gmail.com",
        "SMTP_PORT": "587",
        "SMTP_USERNAME": "your@gmail.com",
        "SMTP_PASSWORD": "your-app-password",
        "SMTP_TLS": "true"
      }
    }
  }
}

Tests

python -m pytest tests/ -v  # 37 tests, all passing

License

MIT

Author

aaameobius-crypto — github.com/aaameobius-crypto

Freelance portfolio: https://ameobius-space.github.io/kwork-portfolio/