diff --git a/docs/release-control/v6/internal/subsystems/api-contracts.md b/docs/release-control/v6/internal/subsystems/api-contracts.md
index fcb1d3e1f..d1179a723 100644
--- a/docs/release-control/v6/internal/subsystems/api-contracts.md
+++ b/docs/release-control/v6/internal/subsystems/api-contracts.md
@@ -10670,3 +10670,14 @@ reasoning and real remediation in
 `docs/qualification/PATROL_ASSISTANT_CUSTOMER_JOURNEY.md`. The repeatable browser
 proof is `scripts/check-patrol-assistant-journey.mjs`. A passing scripted
 response does not establish a useful customer outcome or model qualification.
+
+### Report email shares the canonical SMTP retry verdict
+
+Attachment delivery through `internal/notifications/email_enhanced.go` uses
+notifications-owned `sendEmailWithOptions`; reporting must not introduce a
+separate retry classification. That transport stops on authentication,
+configuration, or rejection failures and preserves temporary-failure retries.
+Its returned failure retains the structured cause and actual attempt count;
+this does not change report API schemas or prove recipient acceptance.
+`internal/notifications/email_retry_class_test.go` verifies the shared transport
+failure boundary with in-memory SMTP replies, not end-to-end report delivery.
diff --git a/docs/release-control/v6/internal/subsystems/notifications.md b/docs/release-control/v6/internal/subsystems/notifications.md
index e02bed3a8..a18ef9ae8 100644
--- a/docs/release-control/v6/internal/subsystems/notifications.md
+++ b/docs/release-control/v6/internal/subsystems/notifications.md
@@ -581,6 +581,21 @@ the queue nor any destination type may keep its own list. This generalises to
 every destination the decision webhook delivery already made for HTTP 4xx in
 `isRetryableWebhookError`.
 
+The SMTP transport's inner retry loop must apply that same classifier after
+an unsuccessful send, before sleeping or attempting another connection.
+Permanent authentication, configuration, and rejection failures return on that
+attempt; transient failures retain up to `MaxRetries + 1` transport attempts.
+The returned error preserves the structured cause and reports the actual
+attempt count, not the configured maximum. This applies equally to ordinary,
+threaded, and attachment email through `sendEmailWithOptions`.
+
+`internal/notifications/email_retry_class_test.go` exercises the real sender
+with in-memory SMTP handshake failures: permanent 550/535/554/501 replies stop
+at one attempt, while transient 421 retains three configured attempts even
+when its prose mentions authentication. It checks classification and the
+reported attempt count. This is transport-only proof, not queue persistence,
+post-DATA acceptance, or an installed recipient receipt.
+
 Dead-lettering early must not lose the notification: `RetryTerminalFailures`
 remains the operator's recovery path, returning eligible retained terminal
 failures to the queue with a fresh budget once the credentials or configuration
diff --git a/internal/notifications/email_enhanced.go b/internal/notifications/email_enhanced.go
index d71045a2c..ffc644fc3 100644
--- a/internal/notifications/email_enhanced.go
+++ b/internal/notifications/email_enhanced.go
@@ -474,10 +474,10 @@ func NewEnhancedEmailManager(config EmailProviderConfig) *EnhancedEmailManager {
 
 // SendEmailWithRetry sends email with retry logic
 // Note: When used with the persistent queue, retry behavior is layered:
-// - Transport retries (this function): up to MaxRetries attempts with RetryDelay between
+// - Transport retries (this function): up to MaxRetries+1 attempts with RetryDelay between
 // - Queue retries: up to MaxAttempts (default 3) with exponential backoff
-// Total attempts = MaxRetries * MaxAttempts (e.g., 3 * 3 = 9 SMTP calls for a single notification)
-// This ensures delivery even during transient failures at either layer.
+// Total attempts = (MaxRetries+1) * MaxAttempts for transient failures.
+// Deterministic failures stop at the first attempt in both layers.
 func (e *EnhancedEmailManager) SendEmailWithRetry(subject, htmlBody, textBody string) error {
 	return e.sendEmailWithOptions(subject, htmlBody, textBody, nil, "")
 }
@@ -528,6 +528,10 @@ func (e *EnhancedEmailManager) sendEmailWithOptions(subject, htmlBody, textBody
 			Int("attempt", attempt).
 			Str("provider", e.config.Provider).
 			Msg("email send attempt failed")
+
+		if !ClassifyNotificationFailureError(err).Retryable() {
+			return fmt.Errorf("email failed after %d attempts: %w", attempt+1, err)
+		}
 	}
 
 	return fmt.Errorf("email failed after %d attempts: %w", e.config.MaxRetries+1, lastErr)
diff --git a/internal/notifications/email_retry_class_test.go b/internal/notifications/email_retry_class_test.go
new file mode 100644
index 000000000..a3e49d75b
--- /dev/null
+++ b/internal/notifications/email_retry_class_test.go
@@ -0,0 +1,64 @@
+package notifications
+
+import (
+	"fmt"
+	"net"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+)
+
+// Exercise the SMTP sender, not just the classifier: its inner retry loop must
+// respect structured replies before the outer queue ever sees the error.
+func TestEmailRetryRespectsSMTPFailureClass(t *testing.T) {
+	for _, tc := range []struct {
+		name         string
+		code         int
+		message      string
+		wantClass    NotificationFailureClass
+		wantAttempts int
+	}{
+		{"rejected despite temporary prose", 550, "temporary timeout", NotificationFailureRejected, 1},
+		{"authentication", 535, "credentials invalid", NotificationFailureAuthentication, 1},
+		{"transaction rejection", 554, "transaction rejected", NotificationFailureRejected, 1},
+		{"configuration", 501, "invalid parameters", NotificationFailureConfiguration, 1},
+		{"transient despite authentication prose", 421, "authentication service unavailable", NotificationFailureServerError, 3},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			var servers sync.WaitGroup
+			originalDial := smtpDialTimeout
+			t.Cleanup(func() { smtpDialTimeout = originalDial; servers.Wait() })
+			attempts := 0
+			smtpDialTimeout = func(string, string, time.Duration) (net.Conn, error) {
+				attempts++
+				client, server := net.Pipe()
+				servers.Add(1)
+				go func() {
+					defer servers.Done()
+					defer server.Close()
+					_ = server.SetDeadline(time.Now().Add(5 * time.Second))
+					_, _ = fmt.Fprintf(server, "%d %s\r\n", tc.code, tc.message)
+				}()
+				return client, nil
+			}
+			manager := NewEnhancedEmailManager(EmailProviderConfig{
+				EmailConfig: EmailConfig{SMTPHost: "smtp.example.test", SMTPPort: 25, From: "pulse@example.test", To: []string{"recipient@example.test"}},
+				MaxRetries:  2,
+			})
+			err := manager.SendEmailWithRetry("test", "<p>test</p>", "test")
+			if err == nil {
+				t.Fatal("expected SMTP failure")
+			}
+			if got := ClassifyNotificationFailureError(err); got != tc.wantClass {
+				t.Errorf("class = %q, want %q", got, tc.wantClass)
+			}
+			if !strings.Contains(err.Error(), fmt.Sprintf("email failed after %d attempts:", tc.wantAttempts)) {
+				t.Errorf("incorrect attempt count in error: %v", err)
+			}
+			if attempts != tc.wantAttempts {
+				t.Errorf("SMTP attempts = %d, want %d", attempts, tc.wantAttempts)
+			}
+		})
+	}
+}