MailVeri MCP Server: How to Verify Emails Directly in Claude, Cursor & Windsurf

AI coding assistants like Claude Desktop, Cursor, Windsurf, and Claude Code have transformed how software and data pipelines are built. With the open-source MailVeri MCP Server, your AI agents can now perform real-time email deliverability checks, filter disposable domains, and clean high-volume prospect lists natively without leaving your chat or IDE interface.

Why AI Agents Need Native Email Verification

Autonomous agents and LLM workflows frequently handle email data: scraping customer leads, parsing webhook payloads, generating onboarding flows, and orchestrating outbound cold email campaigns. However, Large Language Models have a critical blind spot: they cannot check if an email mailbox actually exists.

LLMs can validate syntax using regex, but they cannot perform DNS MX lookups, establish TLS SMTP handshakes, test greylisting defenses, or detect temporary disposable mailboxes. Relying on an AI to generate or scrub lead lists without ground-truth verification leads to:

• High Bounce Rates (>5%): Triggering immediate blacklisting on ESPs like Google Workspace, SendGrid, and Amazon SES.
• Spam Trap Poisoning: Damaging your sender domain reputation when AI-scraped lists contain honeypot traps.
• Wasted Outbound Budget: Sending personalized outreach to dead, invalid, or full mailboxes.

MailVeri’s Model Context Protocol (MCP) integration bridges this gap by giving your AI tools direct, programmatic access to MailVeri’s high-precision deliverability engine.

What is Model Context Protocol (MCP)?

The Model Context Protocol (MCP) is an open-source standard created by Anthropic that allows AI applications (such as Claude Desktop, Cursor, Windsurf, and terminal agents) to connect securely to external tools and data sources. Rather than writing brittle custom plugins or manual API integrations, MCP provides a unified JSON-RPC standard that works identically across all modern AI environments.

The official MailVeri MCP server is open-sourced on GitHub at github.com/mailveri/mailveri-mcp.

Available MailVeri MCP Tools

Once connected, your AI assistant gains access to 6 specialized verification tools:

# Available MailVeri MCP Tools
mailveri_verify_email          # Instant real-time deliverability check
mailveri_get_balance           # Check remaining account credits
mailveri_verify_batch          # Bulk verification for lists and CSV files
mailveri_get_batch_status      # Query batch completion percentage
mailveri_download_batch_result # Fetch categorized deliverable/undeliverable records
mailveri_delete_batch          # Clean up or delete batch jobs

• mailveri_verify_email: Instant deliverability check for a single address in real time. Returns granular deliverability status (VALID, INVALID, DISPOSABLE, ROLE_ACCOUNT, CATCH_ALL, FULL_INBOX).
• mailveri_verify_batch: Dispatches large lists or CSV files to MailVeri’s background async worker cluster.
• mailveri_get_batch_status: Monitors progress percentage and status of background batch verification tasks.
• mailveri_download_batch_result: Downloads clean results categorized by deliverability status.
• mailveri_get_balance: Returns your real-time Universal Credits balance.
• mailveri_delete_batch: Deletes completed list files or cancels active jobs to respect data privacy.

Step-by-Step Client Setup Guides

Setting up MailVeri MCP takes less than two minutes. You will need a MailVeri API key, which you can generate for free in your MailVeri Dashboard.

1. Claude Desktop Configuration

Open your Claude Desktop configuration file (~/Library/Application Support/Claude/claude_desktop_config.json on macOS or %APPDATA%\\Claude\\claude_desktop_config.json on Windows):

{
  "mcpServers": {
    "mailveri": {
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/mailveri/mailveri-mcp",
        "mailveri-mcp"
      ],
      "env": {
        "MAILVERI_API_KEY": "YOUR_MAILVERI_API_KEY"
      }
    }
  }
}

2. Cursor IDE Integration

In Cursor, open your project settings or create a .cursor/mcp.json file in your repository root with the same configuration:

{
  "mcpServers": {
    "mailveri": {
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/mailveri/mailveri-mcp",
        "mailveri-mcp"
      ],
      "env": {
        "MAILVERI_API_KEY": "YOUR_MAILVERI_API_KEY"
      }
    }
  }
}

3. Windsurf Integration

Add the MailVeri server to your Windsurf configuration at ~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "mailveri": {
      "command": "uvx",
      "args": [
        "--from",
        "git+https://github.com/mailveri/mailveri-mcp",
        "mailveri-mcp"
      ],
      "env": {
        "MAILVERI_API_KEY": "YOUR_MAILVERI_API_KEY"
      }
    }
  }
}

4. Claude Code CLI Setup

If you use Claude Code directly in your terminal, register MailVeri with a single command:

claude mcp add \
  --scope project \
  --env MAILVERI_API_KEY=YOUR_API_KEY \
  mailveri -- \
  uvx --from git+https://github.com/mailveri/mailveri-mcp mailveri-mcp

High-Impact AI Prompts & Workflows

Once configured, your AI assistant can execute email hygiene tasks directly in response to conversational prompts. Here are real-world examples:

Scenario A: Automated Waitlist & Lead Scrubbing

“Review all entries in waitlist_signups.csv. Use mailveri_verify_email to check deliverability, remove all temporary disposable domains and invalid inboxes, and export clean prospects to verified_leads.csv.”

Scenario B: Pre-Registration Validation Logic

“Inspect our Next.js API route at app/api/signup/route.ts. Write a helper that calls mailveri_verify_email on form submission and returns a 400 error if the user provides a disposable or non-existent address.”

Scenario C: High-Volume Cold Outreach Guardrail

“Before sending our quarterly product update sequence, submit contacts.csv to mailveri_verify_batch, poll until complete, and filter out any addresses flagged as INVALID or FULL_INBOX.”

Autonomous AI SDR Guardrail: Pairing MailVeri with AgentMail & Outbound Agents

When autonomous AI agents send outbound email through agent inbox providers like AgentMail (agentmail.to), Amazon SES, Instantly, or Smartlead, a single batch of unverified scraped leads can push bounce rates past 5% and suspend the underlying sending domain.

By placing MailVeri immediately before the send step—either through mailveri_verify_email in MCP or a direct REST call—your agent automatically suppresses INVALID, DISPOSABLE, and FULL_INBOX recipients while safely allowing VALID addresses (plus verified ROLE_ACCOUNT inboxes like info@ and contact@ for SMB prospecting, since MailVeri only returns ROLE_ACCOUNT after confirming the mailbox is deliverable and not catch-all):

import os
import requests

MAILVERI_API_KEY = os.environ["MAILVERI_API_KEY"]
AGENTMAIL_API_KEY = os.environ["AGENTMAIL_API_KEY"]

def send_verified_agent_email(inbox_id: str, to_email: str, subject: str, text: str, allow_smb_roles: bool = True):
    # 1. Pre-send deliverability check via MailVeri ($299 for 1M / $0.30 per 1,000; UNKNOWN = 0 credits)
    verify_res = requests.post(
        "https://api.mailveri.com/v1/verify-mail/",
        headers={"Authorization": f"Bearer {MAILVERI_API_KEY}"},
        json={"email": to_email},
        timeout=15,
    ).json()

    status = verify_res.get("status")
    allowed = {"VALID", "ROLE_ACCOUNT"} if allow_smb_roles else {"VALID"}
    if status not in allowed:
        return {"sent": False, "reason": f"Suppressed {to_email} (status={status})"}

    # 2. Dispatch safely via AgentMail once mailbox is confirmed deliverable
    send_res = requests.post(
        f"https://api.agentmail.to/v0/inboxes/{inbox_id}/messages/send",
        headers={"Authorization": f"Bearer {AGENTMAIL_API_KEY}"},
        json={"to": [to_email], "subject": subject, "text": text},
        timeout=15,
    )
    send_res.raise_for_status()
    return {"sent": True, "status": status, "message_id": send_res.json().get("message_id")}

Universal Credits: One Balance for API, Web & MCP

Unlike legacy platforms that require separate wallets for different verification features, MailVeri uses Universal Credits. Every credit in your account works seamlessly across the web dashboard, the REST API, and the Model Context Protocol server. There are no mode switches, no stranded balances, and credits never expire.

Summary & Next Steps

The Model Context Protocol makes email hygiene an effortless, automated capability within your existing AI development workflow. Equip your AI assistants with MailVeri MCP today to eliminate bounce risks, protect sender reputation, and build data pipelines with confidence.

• Explore the complete interactive guide at MailVeri MCP Documentation, take our Visual Tour of MailVeri, or read how Universal Credits and our REST API power agentic pipelines.
• View the source code or star the project on GitHub (mailveri/mailveri-mcp).
• Claim 1,000 free verification credits by creating an account on MailVeri.

Frequently Asked Questions