internal/delivery/dispatcher.go

@@ -396,6 +396,13 @@ func messageForChannel(s Sendable) string {
 	if !isAway(s.Channel) {
 		return s.Body
 	}
+	return AwayMessage(s)
+}
+
+// AwayMessage — the only text an off-box channel may ever carry. Exported so
+// the away sinks share this one rule instead of each inventing a fallback: the
+// summary if we have one, otherwise a fixed generic line. Never the body.
+func AwayMessage(s Sendable) string {
 	if s.Summary != "" {
 		return s.Summary
 	}

internal/delivery/ntfysink/ntfysink.go

@@ -2,10 +2,10 @@
 //
 // ntfy is the away-channel for sev3 (ops soft) nudges, sev4 (ops hard)
 // nudges when present (alongside voice), and reminders when away. the
-// message body is the Sendable's Summary — the minimal-body rule from the
+// message body is delivery.AwayMessage — the minimal-body rule from the
 // spec ("disk low on homesrv," not detail; no shoulder-surf exfil through
-// the relay). voice gets Body; away channels get Summary, enforced at the
-// sink so a phraser bug can't exfil.
+// the relay). the dispatcher already strips detail off away sendables; the
+// sink uses the same helper so it can't leak the body on its own either.
 //
 // ntfy runs locally (docker, 127.0.0.1:8085, deny-all auth). maven publishes
 // with a dedicated user (write-only to maven-* topics) — the credential is a
@@ -69,18 +69,14 @@ func New(cfg Config) (*Sink, error) {
 	}, nil
 }
 
-// Send publishes one notification to ntfy. the body is the Sendable's Summary
-// (minimal body); Title is "maven" (consistent sender identity on the lock
-// screen — the content is in the body). Priority maps from severity/kind so
+// Send publishes one notification to ntfy. the body is the minimal away
+// message (never the full body); Title is "maven" (consistent sender identity
+// on the lock screen — the content is in the body). Priority maps from severity/kind so
 // the phone client can ring differently for an alarm vs a soft ops nudge.
 func (s *Sink) Send(ctx context.Context, d delivery.Sendable) error {
-	body := d.Summary
-	if body == "" {
-		body = d.Body // terse full message beats no message
-	}
-	if body == "" {
-		return fmt.Errorf("ntfysink: empty message for %s", d.Channel)
-	}
+	// never fall back to d.Body: ntfy leaves the box, so an empty summary gets
+	// a generic line instead of the full detail.
+	body := delivery.AwayMessage(d)
 
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost, s.topicURL(), strings.NewReader(body))
 	if err != nil {

internal/delivery/ntfysink/ntfysink_test.go

@@ -147,9 +147,9 @@ func TestSendBodyIsSummaryNotFullBody(t *testing.T) {
 	}
 }
 
-func TestSendFallsBackToBodyWhenSummaryEmpty(t *testing.T) {
-	// a terse full message is better than no message; the phraser should
-	// produce a summary for away-bound severities, but don't silently drop.
+func TestSendNeverSendsTheBodyWhenSummaryEmpty(t *testing.T) {
+	// #368: this used to fall back to the full body. ntfy leaves the box, so
+	// an empty summary gets a fixed generic line plus the rule name instead.
 	rs := newRecordingServer(t, 200, "")
 	srv := httptest.NewServer(rs.handler())
 	defer srv.Close()
@@ -160,12 +160,15 @@ func TestSendFallsBackToBodyWhenSummaryEmpty(t *testing.T) {
 		t.Fatalf("Send: %v", err)
 	}
 	_, _, body, _, _, _ := rs.snapshot()
-	if body != s.Body {
-		t.Fatalf("fallback body: want %q, got %q", s.Body, body)
+	want := delivery.GenericAwayMessage + ": service_down"
+	if body != want {
+		t.Fatalf("body: want %q, got %q", want, body)
 	}
 }
 
-func TestSendRejectsEmptyMessage(t *testing.T) {
+func TestSendNeverSendsAnEmptyMessage(t *testing.T) {
+	// with nothing at all to say we still send the generic line — an away
+	// channel can never carry detail, but it also never goes out blank.
 	rs := newRecordingServer(t, 200, "")
 	srv := httptest.NewServer(rs.handler())
 	defer srv.Close()
@@ -173,9 +176,13 @@ func TestSendRejectsEmptyMessage(t *testing.T) {
 	sink, _ := New(Config{BaseURL: srv.URL, Topic: "maven"})
 	s := nudgeSendable(loop.Sev3, "")
 	s.Body = ""
-	err := sink.Send(context.Background(), s)
-	if err == nil {
-		t.Fatal("want error for empty message")
+	s.RuleName = ""
+	if err := sink.Send(context.Background(), s); err != nil {
+		t.Fatalf("Send: %v", err)
+	}
+	_, _, body, _, _, _ := rs.snapshot()
+	if body != delivery.GenericAwayMessage {
+		t.Fatalf("body: want %q, got %q", delivery.GenericAwayMessage, body)
 	}
 }
 

internal/delivery/telegramsink/telegramsink.go

@@ -2,11 +2,12 @@
 //
 // telegram is the away-channel for sev4 (ops hard) nudges — "disk-fire alarm
 // at 2am routes to telegram, repeat til ack." the message body is the
-// Sendable's Summary — the minimal-body rule from the spec ("disk low on
-// homesrv," not detail; no shoulder-surf exfil through the relay). voice gets
-// Body; away channels get Summary, enforced at the sink so a phraser bug can't
-// exfil. additionally, protect_content=true is passed on every send so the
-// message can't be forwarded out of the chat — locks the minimal body further.
+// delivery.AwayMessage — the minimal-body rule from the spec ("disk low on
+// homesrv," not detail; no shoulder-surf exfil through the relay). the
+// dispatcher already strips detail off away sendables; the sink uses the same
+// helper so it can't leak the body on its own either. additionally,
+// protect_content=true is passed on every send so the message can't be
+// forwarded out of the chat — locks the minimal body further.
 //
 // telegram's bot API is region-restricted for this homesrv — direct egress to
 // api.telegram.org is unreliable. the spec's "away channels leave the box —
@@ -140,18 +141,13 @@ type telegramResp struct {
 }
 
 // Send publishes one message to the configured telegram chat. the body is the
-// Sendable's Summary (minimal body); empty Summary falls back to Body (terse
-// full message beats no message). protect_content=true so a phraser bug (Body
-// leaking detail through Summary) can't be forwarded onward by the user or a
-// chat observer — locks the minimal-body rule at the channel's own last mile.
+// minimal away message (never the full body). protect_content=true so even
+// that can't be forwarded onward by the user or a chat observer — locks the
+// minimal-body rule at the channel's own last mile.
 func (s *Sink) Send(ctx context.Context, d delivery.Sendable) error {
-	body := d.Summary
-	if body == "" {
-		body = d.Body
-	}
-	if body == "" {
-		return fmt.Errorf("telegramsink: empty message for %s", d.Channel)
-	}
+	// never fall back to d.Body: telegram leaves the box, so an empty summary
+	// gets a generic line instead of the full detail.
+	body := delivery.AwayMessage(d)
 
 	payload := sendMessageReq{
 		ChatID:              s.cfg.ChatID,

internal/delivery/telegramsink/telegramsink_test.go

@@ -173,9 +173,9 @@ func TestSendBodyIsSummaryNotFullBody(t *testing.T) {
 	}
 }
 
-func TestSendFallsBackToBodyWhenSummaryEmpty(t *testing.T) {
-	// terse full message beats none; the phraser should produce a summary for
-	// away-bound severities, but don't silently drop.
+func TestSendNeverSendsTheBodyWhenSummaryEmpty(t *testing.T) {
+	// #368: this used to fall back to the full body. telegram leaves the box,
+	// so an empty summary gets a fixed generic line plus the rule name.
 	rs := newRecordingServer(t, 200, "")
 	srv := httptest.NewServer(rs.handler())
 	defer srv.Close()
@@ -188,12 +188,14 @@ func TestSendFallsBackToBodyWhenSummaryEmpty(t *testing.T) {
 	_, _, body, _, _ := rs.snapshot()
 	var req sendMessageReq
 	_ = json.Unmarshal([]byte(body), &req)
-	if req.Text != s.Body {
-		t.Fatalf("fallback text: want %q, got %q", s.Body, req.Text)
+	want := delivery.GenericAwayMessage + ": service_down"
+	if req.Text != want {
+		t.Fatalf("text: want %q, got %q", want, req.Text)
 	}
 }
 
-func TestSendRejectsEmptyMessage(t *testing.T) {
+func TestSendNeverSendsAnEmptyMessage(t *testing.T) {
+	// with nothing at all to say we still send the generic line.
 	rs := newRecordingServer(t, 200, "")
 	srv := httptest.NewServer(rs.handler())
 	defer srv.Close()
@@ -201,9 +203,15 @@ func TestSendRejectsEmptyMessage(t *testing.T) {
 	sink, _ := New(sinkCfg(srv.URL))
 	s := nudgeSendable(loop.Sev4, "")
 	s.Body = ""
-	err := sink.Send(context.Background(), s)
-	if err == nil {
-		t.Fatal("want error for empty message")
+	s.RuleName = ""
+	if err := sink.Send(context.Background(), s); err != nil {
+		t.Fatalf("Send: %v", err)
+	}
+	_, _, body, _, _ := rs.snapshot()
+	var req sendMessageReq
+	_ = json.Unmarshal([]byte(body), &req)
+	if req.Text != delivery.GenericAwayMessage {
+		t.Fatalf("text: want %q, got %q", delivery.GenericAwayMessage, req.Text)
 	}
 }