Reply to Inbox Thread Email
reply-to-inbox-thread-emailPurpose: Reply to one message in a Resend inbox thread. This sends a real email the moment you call it, from the inbox's address to the author of the message, or to everyone on it with replyAll, plus anyone you add in cc or bcc.
Instructions
Purpose: Reply to one message in a Resend inbox thread. This sends a real email the moment you call it, from the inbox's address to the author of the message, or to everyone on it with replyAll, plus anyone you add in cc or bcc. At least one of html or text is required.
NOT for: Passing the message along to someone new without answering it (use forward-inbox-thread-email), or starting a new conversation from the inbox (use send-new-inbox-email).
Returns: The sent email's id.
When to use: User asks to reply to, answer, or follow up on a message in an inbox thread, and has given you the wording. Before using this tool, you MUST double-check with the user that they want to send this reply. Reference the WORDING you are about to send and the SUBJECT of the thread you are answering when double-checking, and warn the user that a reply cannot be undone: a sent email cannot be recalled. You may only use this tool if the user explicitly confirms they want to send the reply after you double-check. You do not choose who the reply answers: by default the reply goes only to the author of the message you answer, at its Reply-To address if it has one. If the inbox sent that message, the reply goes to the people it was sent to. Set replyAll to true when the user wants to reply to everyone on that message. Pass cc or bcc only to add recipients the user named. Mention in the double-check whether you reply to the author only or to everyone, and any cc or bcc recipients you add. A reply can reach at most 50 recipients in total, counted after replyAll adds everyone on the message. Name any attachments in the double-check. Omit subject to use the thread's. Get the emailId from get-inbox-thread.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| cc | No | Email address to copy on the reply, or an array of addresses. Not copied from the message you answer. With replyAll, these join the copied recipients, without duplicates. | |
| bcc | No | Email address to blind-copy on the reply, or an array of addresses. Not copied from the message you answer, even with replyAll. | |
| html | No | HTML body of the reply. Provide html, text, or both. One of the two is required. | |
| text | No | Plain text body of the reply. Provide html, text, or both. One of the two is required. | |
| emailId | Yes | ID of the message being replied to. This is the "id" get-inbox-thread returns for each message in the thread. | |
| 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 | |
| subject | No | Subject for the reply. Omit to use the thread's subject, prefixed with "Re:", which is usually what you want. Max 2000 characters. It cannot be only whitespace or contain a line break. | |
| replyAll | No | Reply to everyone on the message instead of only its author. For a message the inbox received, the reply goes to the author as usual and copies the message's other to recipients and its cc recipients. For a message the inbox sent, it goes to its Reply-To when that is not the inbox's address and copies its to and cc recipients; otherwise it goes to its to recipients and copies its cc recipients. The inbox's own address is left out and duplicates are removed. Defaults to false (author only). | |
| threadId | Yes | Thread ID | |
| attachments | No | Files to attach. Each one needs filename plus content or url. An empty file or a blocked file type (such as .exe) is rejected. Up to 10 files. The content of all files can total at most 25 MB. A url file counts toward the 10 files only, because it is fetched when the email is sent. The whole email, encoded, can be at most 40 MB. | |
| idempotencyKey | No | Optional unique key that prevents duplicate sends on retries (sent as the Idempotency-Key header). Use the same key when retrying the same logical email; use a new key for a different email. Must be 1-256 characters. |