Method Send

internal/outbound/sender.go:178–309

Send normalizes recipients, composes, and sends an email via SMTP relay. Returns a ValidationError for caller errors (bad addresses, no visible recipients) and a plain error for transport failures.

(agent *identity.AgentIdentity, req SendRequest)

// Returns a ValidationError for caller errors (bad addresses, no visible recipients)
// and a plain error for transport failures.
func (s *Sender) Send(agent *identity.AgentIdentity, req SendRequest) (*SendResult, error) {
	agentAddr := strings.ToLower(agent.EmailAddress())
	agentAliases := []string{
		agentAddr,
		strings.ToLower(fmt.Sprintf("agent@%s", s.fromDomain)),
	}

	// Normalize and validate all addresses
	to, err := normalizeAddrs(req.To)
	if err != nil {
		return nil, &ValidationError{Message: fmt.Sprintf("invalid To address: %v", err)}
	}
	cc, err := normalizeAddrs(req.CC)
	if err != nil {
		return nil, &ValidationError{Message: fmt.Sprintf("invalid CC address: %v", err)}
	}
	bcc, err := normalizeAddrs(req.BCC)
	if err != nil {
		return nil, &ValidationError{Message: fmt.Sprintf("invalid BCC address: %v", err)}
	}

	// Remove agent's own addresses
	to = removeAddrs(to, agentAliases)
	cc = removeAddrs(cc, agentAliases)
	bcc = removeAddrs(bcc, agentAliases)

	// Dedupe within each field
	to = dedupe(to)
	cc = dedupe(cc)
	bcc = dedupe(bcc)

	// Cross-field dedupe: To > CC > BCC
	cc = removeAddrs(cc, to)
	bcc = removeAddrs(bcc, to)
	bcc = removeAddrs(bcc, cc)

	// Visible-recipient check: at least one address in To or CC
	if len(to) == 0 && len(cc) == 0 {
		return nil, &ValidationError{Message: "no valid recipients"}
	}

	// Build envelope recipients (To + CC + BCC)
	envelope := make([]string, 0, len(to)+len(cc)+len(bcc))
	envelope = append(envelope, to...)
	envelope = append(envelope, cc...)
	envelope = append(envelope, bcc...)

	// Compose headers
	displayName := agent.Name
	if displayName == "" {
		displayName = agent.EmailAddress()
	}
	// Resolve the sending-verified gate once (it hits the sending_status store),
	// then derive both the header From and the envelope Return-Path from it.
	own := s.useOwnAddressFrom(agent)
	// Envelope MAIL FROM (Return-Path): the aligned custom MAIL FROM
	// (bounce.<domain>) for a verified domain — SPF authenticates the From
	// org-domain → no Gmail "via e2a" — else the e2a-owned relay address