Email Automation Workflows: Orchestrating Gmail and Resend Safely

AI-driven communication platforms must manage email workflows securely to prevent spam and data leaks. Connecting email endpoints (via Gmail OAuth or the Resend API) directly to your MCP server enables your agents to draft templates, alert team members of system warnings, or summarize high-priority messages automatically.

Prerequisites

1. ▸An account with an email provider like Resend or Google Cloud Platform (for Gmail APIs).
2. ▸An API Key or OAuth 2.0 Credentials.
3. ▸A verified sending domain. You cannot send authenticated emails without verifying DNS records first.

The Access Security Model

Never let an AI agent send unverified emails to arbitrary addresses without oversight. A standard security flow looks like this:

[Agent Intent] --> [Email MCP Server] --> [Checks Blocklist/Whitelist] --> [Resend/Gmail API]

Ensure your configuration restricts recipient lists to approved internal domains (e.g. @mycompany.com) to prevent accidental spam or phishing attempts.

Step-by-Step Integration (Resend Example)

If you are building a custom MCP server, you can use the Resend SDK to dispatch emails. Here is a TypeScript snippet demonstrating domain-whitelisting logic:

import { Resend } from 'resend';
const resend = new Resend(process.env.RESEND_API_KEY);

async function sendTeamNotification(to: string, subject: string, htmlContent: string) {
  // STRICT: Only allow emails ending in @mycompany.com
  const domainWhitelist = /@mycompany\.com$/;
  if (!domainWhitelist.test(to)) {
    throw new Error("Security Error: Recipient address is outside the allowed corporate domain whitelist.");
  }
  
  return await resend.emails.send({
    from: 'mcp-agent@mycompany.com',
    to,
    subject,
    html: htmlContent
  });
}

Best Practices

• ▸Drafts Over Direct Send: When interacting with external customers, configure your MCP server to create a draft in Gmail rather than sending it immediately. A human should review the draft before clicking send.
• ▸Rate Limiting: AI agents can generate emails incredibly fast. Enforce strict rate limits on your endpoints to ensure you don't get blocked by your email provider.

Troubleshooting

• ▸403 Forbidden / Domain Unverified: You are trying to send an email from a domain you don't own. Ensure your Resend/Gmail domain is fully verified in your DNS provider (TXT, SPF, DKIM records).
• ▸Silent Failures: If the email sends but never arrives, it likely triggered a spam filter due to AI-generated language sounding promotional. Check your provider's spam score analytics.

Using with OpenAI Codex

To use this MCP server with the OpenAI Codex CLI, you can add it to your configuration using the codex mcp add command:

codex mcp add --name email-automation --command "npx @modelcontextprotocol/server-email-automation"

(Note: Depending on the server, you may need to append arguments or use --env flags for environment variables as described in the configuration section above)