Send Transactional Email With Resend

Send transactional emails and check delivery status with the Resend API. The gateway injects your API key automatically, so agents never see it.

Overview

OneCLI connects AI agents to Resend using an API key. Agents can send transactional emails, check delivery status, and manage contacts. The gateway injects the API key into requests to the Resend API automatically.

This is useful for agents that need to send notifications, alerts, or reports by email without configuring SMTP.

Setup

1. Create an API key in Resend

   Go to resend.com/api-keys and create a new API key. Choose the appropriate permission level (sending access or full access). Copy the key.

2. Connect in OneCLI

   Open the OneCLI dashboard, go to Connections > Resend, and paste your API key.

   

   The Resend connect window in OneCLI.

What agents can do

• Send emails with specified from address, recipients, subject, and HTML or plain text body
• Send emails with attachments
• Check the delivery status of a sent email (delivered, bounced, complained)
• List sent emails and their statuses
• Manage contacts and audiences (create, list, update, delete contacts)
• Send batch emails to multiple recipients
• Use verified domains for sending

Controlling access

Access is per agent: grant the connection to each agent that needs it, choosing per tool what runs freely, what needs human approval, and what stays blocked — a read-only agent is a single grant. Organization rules add guardrails on top, like rate limits and blanket blocks. Everything is checked before credential injection, so a blocked request never reaches Resend.