Send New Inbox Email
send-new-inbox-emailSend a new email from a Resend inbox to start a new thread, delivering it immediately to recipients and saving it in the inbox's sent folder.
Instructions
Purpose: Send a new email from a Resend inbox, starting a new thread in that inbox. This sends a real email the moment you call it, from the inbox's address to the recipients in to, cc, and bcc. The sent message shows up in the inbox's sent folder, and answers to it land in the same thread. A subject and at least one of html or text are required.
NOT for: Answering a message already in an inbox thread (use reply-to-inbox-thread-email), passing one along (use forward-inbox-thread-email), or saving a message to send later (use create-inbox-draft). Not for mail from an address that is not an inbox (use send-email, whose mail never appears in an inbox).
Returns: The sent email's id.
When to use: User asks to send, write, or email someone from an inbox ("send an email from the support inbox", "email the customer as sales@"), and has given you the recipients and the wording. Before using this tool, you MUST double-check with the user that they want to send this email. Reference the RECIPIENTS, the SUBJECT, and the WORDING you are about to send when double-checking, and warn the user that a sent email cannot be recalled. You may only use this tool if the user explicitly confirms they want to send the email after you double-check. The email is created as a draft in the inbox and then sent: if sending fails once the draft exists, the error names the draft ID, so retry with send-inbox-draft or discard it with remove-inbox-draft rather than composing it again. Get the inbox ID from list-inboxes.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| cc | No | Email address to copy, or an array of addresses. Across to, cc, and bcc an email can carry at most 50 recipients in total. | |
| to | Yes | Recipient email address (e.g. "customer@example.com"), or an array of addresses to reach several. Across to, cc, and bcc an email can carry at most 50 recipients in total. | |
| bcc | No | Email address to blind-copy, or an array of addresses. Across to, cc, and bcc an email can carry at most 50 recipients in total. | |
| html | No | HTML body of the email. Provide html, text, or both; one of the two is required. | |
| text | No | Plain text body of the email. Provide html, text, or both; one of the two is required. | |
| headers | No | Optional custom email headers as key/value pairs (e.g. {"X-Entity-Ref-ID": "unique-id"}). Header names cannot be empty, and names and values cannot contain line breaks or null characters. In-Reply-To, References and Reply-To are reserved: Resend sets them, and passing any of them, in any letter case, fails. | |
| inboxId | Yes | Inbox ID, or the inbox email address (e.g. "support@example.com"). Not the Resend receiving address. | |
| subject | Yes | Subject of the email. Max 2000 characters. It cannot be only whitespace or contain a line break. | |
| idempotencyKey | No | Optional unique key that prevents duplicate drafts and sends on retries (sent as the Idempotency-Key header on both calls). Use the same key when retrying the same logical email; use a new key for a different email. Must be 1-256 characters. |