phraser: the reminder summary is cut in runes, and silence is an error (V-620)

Three defects in internal/phraser, all of the shape "reports done when
nothing happened".

The reminder summary was cut in bytes: `len(s) > 60` and `s[:57]`, in two
copies (Stub.PhraseReminder and LLMPhraser.PhraseReminder). On Russian a
letter is two bytes, so the cut fell at about 28 letters instead of 60 and
landed inside a letter about half the time. Sendable.Summary is what
voicesink hands to piper and what the telegram sink posts, so the half rune
was spoken and sent. One rune-counting helper now, shared by both. The test
that covered this was ASCII, which is what let the arithmetic stand.

The evidence branch of PhraseQuery and the bare-prose tail of PhraseChat
both returned ("", nil) when the server answered and the model wrote no
tokens. The knowledge branch has guarded that with errEmptyResponse since it
was written; these two did not. The daemon's callers check for the empty
string and paper over it, so the visible cost was the eval, which scored a
silent model as bad phrasing rather than as a failure, and a log line that
never appeared.

Stub.PhraseReminder set no Mood. Its sibling PhraseNudge sets "neutral" and
says in a comment why: the Stub is a production fallback and owes the output
contract a value. The zero value is not one of the five moods.

No prompt and no spoken wording changed, so the phrasing eval is unmoved.

internal/phraser/failure_test.go

@@ -78,3 +78,36 @@ func TestEmptyKnowledgeAnswerIsAnError(t *testing.T) {
 		t.Errorf("error = %v; want it to name the empty response", err)
 	}
 }
+
+// The other two paths, which had no such guard. The evidence branch of
+// PhraseQuery and PhraseChat both returned ("", nil) off a server that produced
+// no tokens — an empty answer reported as a successful phrasing. The daemon's
+// callers check for the empty string and paper over it; the eval does not, and
+// scored a silent model as bad phrasing rather than as a failure.
+func TestEmptyAnswerIsAnErrorOnEveryPath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.Write([]byte(`{"choices":[{"message":{"content":""}}]}`))
+	}))
+	t.Cleanup(srv.Close)
+	p := NewLLMPhraserAt(srv.URL, Config{})
+
+	t.Run("evidence", func(t *testing.T) {
+		got, err := p.PhraseQuery(context.Background(), "сколько воды я выпил", []string{"два литра"})
+		if err == nil {
+			t.Fatal("an empty response scored as an answer")
+		}
+		if !isFallback(t, fbQuerySources, "два литра", got) {
+			t.Errorf("fallback text = %q, want a %q variant", got, fbQuerySources)
+		}
+	})
+	t.Run("chat", func(t *testing.T) {
+		got, err := p.PhraseChat(context.Background(), "как дела", nil)
+		if err == nil {
+			t.Fatal("an empty response scored as an answer")
+		}
+		if !isFallback(t, fbChat, "", got) {
+			t.Errorf("fallback text = %q, want a %q variant", got, fbChat)
+		}
+	})
+}

internal/phraser/llmphraser.go

@@ -299,6 +299,16 @@ func (p *LLMPhraser) PhraseQuery(ctx context.Context, utterance string, notes []
 	if text != "" {
 		return text, nil
 	}
+	if raw == "" {
+		// Same guard the knowledge branch above has had since it was written,
+		// and this branch did not: the server answered and the model wrote
+		// nothing, which returned ("", nil) — an empty answer reported as a
+		// successful phrasing. The daemon's callers happen to check for the
+		// empty string, so it read as a silent fallback there; the eval scored
+		// it as bad phrasing rather than as the failure it is, and nothing on
+		// either path logged that the model had produced no tokens.
+		return SourcesFallback(strings.Join(notes, "; ")), errEmptyResponse
+	}
 	return raw, nil
 }
 
@@ -375,7 +385,13 @@ func (p *LLMPhraser) PhraseChat(ctx context.Context, utterance string, history [
 	if i := strings.IndexByte(resp, '\n'); i >= 0 {
 		resp = resp[:i]
 	}
-	return strings.TrimSpace(resp), nil
+	if resp = strings.TrimSpace(resp); resp == "" {
+		// The model was up and wrote nothing. Same rule as PhraseQuery: the
+		// fallback keeps the turn alive and the failure stays visible, rather
+		// than ("", nil) telling the caller the chat path succeeded.
+		return ChatFallback(), fmt.Errorf("phrase chat: %w", errEmptyResponse)
+	}
+	return resp, nil
 }
 
 func (p *LLMPhraser) PhraseReminder(ctx context.Context, d loop.ReminderDecision) (delivery.PhrasedReminder, error) {
@@ -414,11 +430,9 @@ func (p *LLMPhraser) PhraseReminder(ctx context.Context, d loop.ReminderDecision
 	if mood == "" {
 		mood = "neutral"
 	}
-	summary := body
-	if len(summary) > 60 {
-		summary = summary[:57] + "..."
-	}
-	return delivery.PhrasedReminder{Decision: d, Body: body, Summary: summary, Mood: mood}, nil
+	return delivery.PhrasedReminder{
+		Decision: d, Body: body, Summary: reminderSummary(body), Mood: mood,
+	}, nil
 }
 
 func (p *LLMPhraser) chat(ctx context.Context, userPrompt string) (string, error) {

internal/phraser/phraser.go

@@ -115,11 +115,32 @@ func (s *Stub) PhraseReminder(_ context.Context, d loop.ReminderDecision) (deliv
 	if text == "" {
 		text = "reminder"
 	}
-	summary := text
-	if len(summary) > 60 {
-		summary = summary[:57] + "..."
+	// Mood, for the same reason PhraseNudge sets it: the Stub is a production
+	// fallback, so it owes the output contract a value. This one was left at the
+	// zero value, which is not one of the five moods.
+	return delivery.PhrasedReminder{
+		Decision: d, Body: text, Summary: reminderSummary(text), Mood: "neutral",
+	}, nil
+}
+
+// summaryLimit — how much of a reminder goes to the away channels.
+const summaryLimit = 60
+
+// reminderSummary shortens a reminder body to the away-channel summary.
+//
+// Counted in runes. Both copies of this counted bytes — `len(s) > 60` and
+// `s[:57]` — and on a Russian reminder that is wrong twice. A Cyrillic letter is
+// two bytes, so the cut fell at about 28 letters rather than 60; and byte 57
+// lands inside a letter about half the time, so the summary ended in half a
+// rune. That is not cosmetic: Sendable.Summary is the text voicesink hands to
+// piper and the text the telegram sink posts, so the broken byte was spoken and
+// sent.
+func reminderSummary(body string) string {
+	r := []rune(body)
+	if len(r) <= summaryLimit {
+		return body
 	}
-	return delivery.PhrasedReminder{Decision: d, Body: text, Summary: summary}, nil
+	return string(r[:summaryLimit-3]) + "..."
 }
 
 // phraseNudge — the per-rule templates. each reads the context the predicate

internal/phraser/phraser_test.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"testing"
 	"time"
+	"unicode/utf8"
 
 	"github.com/kami/maven/internal/delivery"
 	"github.com/kami/maven/internal/dialogue"
@@ -185,6 +186,34 @@ func TestPhraseReminderTruncatesLongSummary(t *testing.T) {
 	}
 }
 
+// The same truncation, in the language she actually speaks. The test above is
+// ASCII, which is what let the byte arithmetic stand: `len(s) > 60` and `s[:57]`
+// cut a Russian reminder at about 28 letters instead of 60, and landed inside a
+// letter about half the time. Summary is what voicesink hands to piper and what
+// the telegram sink posts, so half a rune was spoken and sent.
+func TestPhraseReminderSummaryCountsRunesNotBytes(t *testing.T) {
+	long := "позвонить маме и забрать посылку из пункта выдачи на соседней улице до восьми вечера"
+	rd := loop.ReminderDecision{
+		Reminder: store.Reminder{Payload: `{"text":"` + long + `"}`},
+		State:    loop.State{Now: time.Now().UTC()},
+	}
+	pr, _ := NewStub().PhraseReminder(context.Background(), rd)
+	if !utf8.ValidString(pr.Summary) {
+		t.Fatalf("summary is not valid UTF-8, it was cut mid-letter: %q", pr.Summary)
+	}
+	if n := utf8.RuneCountInString(pr.Summary); n > summaryLimit {
+		t.Fatalf("summary = %d runes, want at most %d: %q", n, summaryLimit, pr.Summary)
+	}
+	// The cut must be near the limit, not near half of it. A byte count would
+	// stop at 28 letters here.
+	if n := utf8.RuneCountInString(pr.Summary); n < summaryLimit-5 {
+		t.Fatalf("summary = %d runes, cut far too early — counted in bytes? %q", n, pr.Summary)
+	}
+	if pr.Mood == "" {
+		t.Error("Mood is empty; the Stub is a production fallback and owes the contract a mood")
+	}
+}
+
 func TestPhraseReminderNonJSONPayload(t *testing.T) {
 	// a payload that isn't JSON → the phraser falls back to the raw string.
 	rd := loop.ReminderDecision{