Glossary·Inbound

Structured reply event (reply.event)

A structured object representing an inbound email reply. injection_score + sender_reputation are computed on every event; intent, entities, and urgency are added when opt-in classification is enabled.

A structured reply event (reply.event) is the structured object Mails.ai delivers to your agent when an inbound email arrives. Every reply received by an agent address — whether a response to an outbound the agent sent, or an unsolicited inbound to its public-facing address — is normalized into a structured reply event before it reaches your code.

What is in the event

Two fields are computed on every event, plus the raw body for fallback:

injection_score — 0–1 prompt-injection risk. See injection_score.
sender_reputation— reputation graph score for the sender domain + identity. Workspace-scoped today, designed to propagate network-wide as the cohort grows.

Enable opt-in classification (+$0.003 per event) and three more fields are populated:

intent — the classified action: one of schedule_demo, request_pricing, unsubscribe, refund_request, abuse_attempt, support_request, express_interest, general_inquiry.
entities— structured data extracted from the body: dates, amounts, names, emails, durations, timezones.
urgency— 0–1 score. Threshold for paging your agent vs. queueing for batch.

Why it matters

Without structured reply events, every agent that reads inbound email re-implements MIME parsing, threading, intent classification, and entity extraction. Each is a class of bugs. Structured reply events let your agent code switch against structured fields rather than regex through bytes — here with opt-in classification enabled:

agent.onReply((event) => {
  if (event.injection_score > 0.5) return;
  switch (event.intent) {
    case "schedule_demo": return calendar.createEvent(event.entities);
    case "unsubscribe": return suppressionList.add(event.from);
  }
});