{"uid":"cap_vvw-m6xMFmwpDBzVpi7MQ","slug":"agentmail-reply-all-de914cd3","name":"AgentMail Reply All","description":"Reply All Message","url":"https://mpp.api.agentmail.to/v0/inboxes/:inbox_id/messages/:message_id/reply-all?utm_source=zero.xyz","method":"POST","headers":{},"bodySchema":{"type":"object","title":"ReplyAllMessageRequest","properties":{"html":{"type":"string","title":"MessageHtml","description":"HTML body of message."},"text":{"type":"string","title":"MessageText","description":"Plain text body of message."},"labels":{"type":"array","items":{"type":"string"},"title":"MessageLabels","description":"Labels of message."},"headers":{"type":"object","title":"SendMessageHeaders","description":"Headers to include in message.","additionalProperties":{"type":"string"}},"reply_to":{"oneOf":[{"type":"string"},{"type":"array","items":{"type":"string"}}],"title":"Addresses"},"attachments":{"type":"array","items":{"type":"object","title":"SendAttachment","properties":{"url":{"type":"string","description":"URL to the attachment."},"content":{"type":"string","description":"Base64 encoded content of attachment."},"filename":{"type":"string","title":"AttachmentFilename","description":"Filename of attachment."},"content_id":{"type":"string","title":"AttachmentContentId","description":"Content ID of attachment."},"content_type":{"type":"string","title":"AttachmentContentType","description":"Content type of attachment."},"content_disposition":{"enum":["inline","attachment"],"type":"string","title":"AttachmentContentDisposition","description":"Content disposition of attachment."}}},"title":"SendMessageAttachments","description":"Attachments to include in message."}}},"responseSchema":{"type":"object","title":"SendMessageResponse","required":["message_id","thread_id"],"properties":{"thread_id":{"type":"string","title":"ThreadId","description":"ID of thread."},"message_id":{"type":"string","title":"MessageId","description":"ID of message."}}},"example":null,"exampleRequest":null,"tags":["email","inboxes","domains","drafts","threads","webhooks","messaging","ai","social"],"displayCostAmount":"0.01","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"unknown","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.01/call","primary":{"kind":"static","protocol":"mpp","network":"tempo","amountUsd":"0.01","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"mpp","network":"tempo","amountUsd":"0.01","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_oqxy6QoLQlOEe0iO39kyZ","protocol":"mpp","methodType":"crypto","chain":"tempo","mode":"charge","costAmount":"0.01","costPer":"request","priority":0,"asset":null,"unit":"request","depositMicros":null,"planRef":null}],"brandName":"AgentMail","brandSlug":"agentmail","brandBaseUrl":"https://agentmail.to","brandDocsUrl":"https://docs.agentmail.to","whatItDoes":"Sends a reply-all to an existing email message, addressing all original recipients in the thread from a specific inbox","exampleAgentPrompt":"Reply all to that email thread in inbox 'support-bot@agentmail.to' (inbox ID: inbox_abc123, message ID: msg_xyz789) and say: 'Thanks everyone — we've resolved the issue and will follow up shortly.'","exampleUseCases":null,"resultDescription":"Returns a JSON object containing the message_id of the newly sent reply-all message and the thread_id of the conversation thread it belongs to.","failureModes":["Invalid inbox_id or message_id returns 404 Not Found","Missing or invalid Authorization Bearer token returns 401 Unauthorized","Malformed request body (e.g. neither html nor text provided) may return 400 Bad Request","Attachment URL unreachable or content not base64-encoded returns an error","inbox_id does not have permission to send messages returns 403 Forbidden"],"whenToPreferThis":"Use this endpoint when an AI agent needs to respond to all participants on an existing email thread — not just the sender — within an AgentMail-managed inbox. Prefer this over a standard reply when the original message had multiple recipients (To/CC) that all need to receive the response. Ideal for automated customer support, team coordination, or multi-party AI-driven email workflows.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-12T18:40:36.015Z","isFirstParty":false,"canonicalSlug":"agentmail-reply-all-de914cd3"}