Agent Email Inbox Skill

npx skills add resend/resend-skills

Email → Resend Inbox → Webhook → Your Server → Validate
                                                   ↓
                                   Process or Reject → Reply in the thread

import { Resend } from 'resend';

const resend = new Resend(process.env.RESEND_API_KEY);
const ALLOWED_SENDERS = ['your@email.com'];

// `from` can be `Name <address>`, so compare the address only
const senderAddress = (from) => {
  const match = from.match(/<([^<>]+)>\s*$/);
  return (match ? match[1] : from).trim().toLowerCase();
};

async function handler(req) {
  const payload = await req.text();

  const event = resend.webhooks.verify({
    payload,
    headers: {
      id: req.headers.get('svix-id'),
      timestamp: req.headers.get('svix-timestamp'),
      signature: req.headers.get('svix-signature'),
    },
    webhookSecret: process.env.RESEND_WEBHOOK_SECRET,
  });

  if (event.type === 'inbox.email.received') {
    const { inbox_id, thread_id, email_id, email } = event.data;

    if (!email || !ALLOWED_SENDERS.includes(senderAddress(email.from))) {
      return new Response('OK', { status: 200 });
    }

    const thread = {
      inboxId: inbox_id,
      threadId: thread_id,
      emailId: email_id,
    };
    const { data: fullEmail } = await resend.inboxes.threads.emails.get(thread);

    const answer = await processEmailForAgent(fullEmail);

    await resend.inboxes.threads.emails.reply({ ...thread, text: answer });
  }

  return new Response('OK', { status: 200 });
}