# AgentMail Update Draft > AgentMail Update Draft is a free API for AI agents from AgentMail at mpp.api.agentmail.to, Free, status unknown (last checked 2026-10-11). Updates an existing email draft in an AgentMail inbox, allowing modifications to recipients, subject, body, scheduling, and other fields ## Facts - Endpoint: PATCH https://mpp.api.agentmail.to/v0/inboxes/:inbox_id/drafts/:draft_id?utm_source=zero.xyz - Price: Free - Status: unknown - Last checked: 2026-10-11 - Activations on Zero: 0 - Provider: AgentMail - Docs: https://docs.agentmail.to - Website: https://agentmail.to - Tags: email, inboxes, domains, drafts, threads, webhooks, messaging, ai, social - Canonical page: https://www.zero.xyz/c/agentmail-draft-id-9aa462ca - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BCvNH0JhGEp4kKwKIcGSG Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability agentmail-draft-id-9aa462ca -d '' ``` Example prompt: Update my draft 'draft_abc123' in inbox 'inbox_xyz456' on AgentMail — change the subject to 'Meeting Follow-Up', update the body text to 'Hi, just following up on our meeting. Let me know your thoughts.', and schedule it to send at 2025-06-01T09:00:00Z. ## When to prefer this Use this endpoint when an AI agent needs to revise an already-created email draft before sending — such as updating recipient lists, changing subject or body content, or adjusting a scheduled send time. Prefer this over creating a new draft when an existing draft_id is known and only partial fields need modification. ## Known failure modes - 404 if inbox_id or draft_id does not exist - 401 if Bearer token is missing or invalid - 400 if request body fields are malformed (e.g. invalid email address format or invalid date-time for send_at) - 422 if required path parameters inbox_id or draft_id are not provided - 409 if draft has already been sent and cannot be modified ## How this service works Update Draft ## Output Returns the full updated Draft object including draft_id, inbox_id, to, cc, bcc, subject, html, text, reply_to, labels, preview, send_at, client_id, references, created_at, and updated_at timestamps. ## Request schema (JSON Schema) ```json { "type": "object", "title": "UpdateDraftRequest", "properties": { "cc": { "type": "array", "items": { "type": "string" }, "title": "DraftCc", "description": "Addresses of CC recipients. In format `username@domain.com` or `Display Name `." }, "to": { "type": "array", "items": { "type": "string" }, "title": "DraftTo", "description": "Addresses of recipients. In format `username@domain.com` or `Display Name `." }, "bcc": { "type": "array", "items": { "type": "string" }, "title": "DraftBcc", "description": "Addresses of BCC recipients. In format `username@domain.com` or `Display Name `." }, "html": { "type": "string", "title": "DraftHtml", "description": "HTML body of draft." }, "text": { "type": "string", "title": "DraftText", "description": "Plain text body of draft." }, "send_at": { "type": "string", "title": "DraftSendAt", "format": "date-time", "description": "Time at which to schedule send draft." }, "subject": { "type": "string", "title": "DraftSubject", "description": "Subject of draft." }, "reply_to": { "type": "array", "items": { "type": "string" }, "title": "DraftReplyTo", "description": "Reply-to addresses. In format `username@domain.com` or `Display Name `." } } } ``` ## Response schema (JSON Schema) ```json { "type": "object", "title": "Draft", "required": [ "inbox_id", "draft_id", "labels", "updated_at", "created_at" ], "properties": { "cc": { "type": "array", "items": { "type": "string" }, "title": "DraftCc", "description": "Addresses of CC recipients. In format `username@domain.com` or `Display Name `." }, "to": { "type": "array", "items": { "type": "string" }, "title": "DraftTo", "description": "Addresses of recipients. In format `username@domain.com` or `Display Name `." }, "bcc": { "type": "array", "items": { "type": "string" }, "title": "DraftBcc", "description": "Addresses of BCC recipients. In format `username@domain.com` or `Display Name `." }, "html": { "type": "string", "title": "DraftHtml", "description": "HTML body of draft." }, "text": { "type": "string", "title": "DraftText", "description": "Plain text body of draft." }, "labels": { "type": "array", "items": { "type": "string" }, "title": "DraftLabels", "description": "Labels of draft." }, "preview": { "type": "string", "title": "DraftPreview", "description": "Text preview of draft." }, "send_at": { "type": "string", "title": "DraftSendAt", "format": "date-time", "description": "Time at which to schedule send draft." }, "subject": { "type": "string", "title": "DraftSubject", "description": "Subject of draft." }, "draft_id": { "type": "string", "title": "DraftId", "description": "ID of draft." }, "inbox_id": { "type": "string", "title": "InboxId", "description": "The ID of the inbox." }, "reply_to": { "type": "array", "items": { "type": "string" }, "title": "DraftReplyTo", "description": "Reply-to addresses. In format `username@domain.com` or `Display Name `." }, "client_id": { "type": "string", "title": "DraftClientId", "description": "Client ID of draft." }, "created_at": { "type": "string", "format": "date-time", "description": "Time at which draft was created." }, "references": { "type": "array", "items": { "type": "string" }, "description": "IDs of previous messages in thread." }, "updated_at": { "type": "string", "title": "DraftUpdatedAt", "format": "date-time", "description": "Time at which draft was last updated." }, "att … (truncated) ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentmail-draft-id-9aa462ca/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from mpp.api.agentmail.to](https://www.zero.xyz/host/mpp.api.agentmail.to/llms.txt)