internal/phraser/broken_json_test.go

@@ -0,0 +1,54 @@
+package phraser
+
+import (
+	"errors"
+	"strings"
+	"testing"
+)
+
+// A reply that starts a JSON object and never finishes it is a failed
+// generation, not a reply. Before this, the parser returned ("", "") for these
+// and every caller then shipped the raw fragment as the thing Maven said. A
+// real run produced replies of literally "{" and "{\n  \"".
+func TestParseResponseMoodRejectsUnfinishedJSON(t *testing.T) {
+	for _, raw := range []string{
+		`{`,
+		"{\n  \"",
+		`{"response": "неполн`,
+		`{"response": "текст", "mood":`,
+	} {
+		text, mood, err := parseResponseMood(raw)
+		if !errors.Is(err, errBrokenJSON) {
+			t.Errorf("parseResponseMood(%q) err = %v, want errBrokenJSON", raw, err)
+		}
+		if text != "" || mood != "" {
+			t.Errorf("parseResponseMood(%q) leaked %q/%q — a fragment must never come back as a reply", raw, text, mood)
+		}
+	}
+}
+
+// Bare prose is still fine. Small models sometimes answer without any JSON at
+// all, and that reply is usable — so the new error must not swallow it.
+func TestParseResponseMoodAllowsBareProse(t *testing.T) {
+	for _, raw := range []string{
+		"норм, а ты как?",
+		"вот что я нашла: ключ у соседа",
+	} {
+		text, mood, err := parseResponseMood(raw)
+		if err != nil {
+			t.Errorf("parseResponseMood(%q) err = %v, want nil", raw, err)
+		}
+		// No JSON means no fields; the caller ships raw as-is.
+		if text != "" || mood != "" {
+			t.Errorf("parseResponseMood(%q) = %q/%q, want empty", raw, text, mood)
+		}
+	}
+}
+
+// The measured failure: the model wants more than 400 characters and the old
+// grammar cut it off mid-word. Guards the bound against being tightened back.
+func TestGrammarStringBoundHasRoomForARealAnswer(t *testing.T) {
+	if !strings.Contains(responseGrammar, "{0,1000}") {
+		t.Error("grammar string bound is not 1000; 400 truncated real replies mid-word (see the comment on responseGrammar)")
+	}
+}

internal/phraser/eval/address_multi_test.go

@@ -31,3 +31,35 @@ func TestAddressDeduplicates(t *testing.T) {
 		t.Errorf("detail repeats the same break %d times: %q", n, res.Detail)
 	}
 }
+
+// The fragments a real run produced. All of them scored as non-empty replies
+// before checkNonEmpty looked for letters.
+func TestNonEmptyNeedsLetters(t *testing.T) {
+	for _, body := range []string{
+		"{",
+		"{\n  \"",
+		"15-16",
+		`{"`,
+		"   ",
+		"...",
+	} {
+		if got := checkNonEmpty(body); got.Pass {
+			t.Errorf("checkNonEmpty(%q) passed — that is not a reply", body)
+		}
+	}
+}
+
+// And it must not start failing real replies. Latin counts as well as Cyrillic:
+// answers about ssd or vpn are legitimately part English.
+func TestNonEmptyAcceptsRealReplies(t *testing.T) {
+	for _, body := range []string{
+		"норм, а ты как?",
+		"вот что я нашла: ключ у соседа",
+		"ssd быстрее hdd.",
+		"9 минут.",
+	} {
+		if got := checkNonEmpty(body); !got.Pass {
+			t.Errorf("checkNonEmpty(%q) failed: %s", body, got.Detail)
+		}
+	}
+}

internal/phraser/eval/checks.go

@@ -623,11 +623,24 @@ const (
 	CheckEllipsis = "ellipsis" // she finished the sentence
 )
 
+// A reply needs words in it, not just characters. This check used to test for a
+// non-empty string, which scored 27/27 on a run where two replies were "{" and
+// "{\n  \"" — punctuation passed as content. Braces, quotes, digits and spaces
+// are all empty in the only sense that matters.
+//
+// Digits alone fail too, and that is deliberate: the same run answered "сколько
+// варить яйцо вкрутую?" with "15-16". No unit, no words, and it is also the
+// wrong number. Whatever that is, it is not something she said.
 func checkNonEmpty(body string) Result {
 	if strings.TrimSpace(body) == "" {
 		return Result{CheckNonEmpty, false, "empty reply"}
 	}
-	return Result{CheckNonEmpty, true, ""}
+	for _, r := range body {
+		if unicode.IsLetter(r) {
+			return Result{CheckNonEmpty, true, ""}
+		}
+	}
+	return Result{CheckNonEmpty, false, fmt.Sprintf("no letters in the reply %q — punctuation or digits only", strings.TrimSpace(body))}
 }
 
 // checkEllipsis — a reply ending in "…" or "..." is a generation that ran out of

internal/phraser/grammar_test.go

@@ -97,7 +97,10 @@ func TestGrammarStringRuleIsNotASCIIOnly(t *testing.T) {
 // Russian body with an escaped quote inside, hand-built to test the contract.
 func TestGrammarShapedJSONParses(t *testing.T) {
 	raw := `{"response": "он сказал \"привет\" и ушёл.\nвот так.", "mood": "confused"}`
-	text, mood := parseResponseMood(raw)
+	text, mood, err := parseResponseMood(raw)
+	if err != nil {
+		t.Fatalf("grammar-shaped JSON did not parse: %v", err)
+	}
 	if want := "он сказал \"привет\" и ушёл.\nвот так."; text != want {
 		t.Errorf("response = %q, want %q", text, want)
 	}

internal/phraser/llmphraser.go

@@ -190,7 +190,12 @@ func (p *LLMPhraser) PhraseNudge(ctx context.Context, c loop.Candidate) (deliver
 	if err != nil {
 		return delivery.PhrasedNudge{}, err
 	}
-	body, mood := parseResponseMood(resp)
+	body, mood, perr := parseResponseMood(resp)
+	if perr != nil {
+		// Truncated JSON. Not a nudge — use the plain Russian fallback.
+		log.Printf("phraser: PhraseNudge: %v", perr)
+		body, mood = "", ""
+	}
 	if body == "" {
 		// fallback: try old body/summary format
 		body, _ = parsePhrase(resp)
@@ -216,11 +221,16 @@ func (p *LLMPhraser) PhraseQuery(ctx context.Context, utterance string, notes []
 		// prompt is the single tested source in router.KnowledgePrompt.
 		sys := persona.Prepend(p.cfg.ContextBlock, router.KnowledgePrompt())
 		prompt := fmt.Sprintf("Пользователь спрашивает: \"%s\".", utterance)
-		resp, err := p.chatWithSystem(ctx, sys, prompt, 256)
+		resp, err := p.chatWithSystem(ctx, sys, prompt, 768)
 		if err != nil || resp == "" {
 			return "не знаю.", nil
 		}
-		if text, _ := parseResponseMood(resp); text != "" {
+		text, _, perr := parseResponseMood(resp)
+		if perr != nil {
+			log.Printf("phraser: PhraseQuery: %v", perr)
+			return "не знаю.", nil
+		}
+		if text != "" {
 			return text, nil
 		}
 		return resp, nil
@@ -233,14 +243,19 @@ func (p *LLMPhraser) PhraseQuery(ctx context.Context, utterance string, notes []
 		`Он спрашивает: "%s". В твоих заметках по этому вопросу написано: "%s". Ответь ему коротко и своими словами. Если в заметках ответа нет — так и скажи.`,
 		utterance, strings.Join(notes, `"; "`),
 	)
-	resp, err := p.chatWithSystem(ctx, sys, prompt, 256)
-	if err != nil {
+	resp, err := p.chatWithSystem(ctx, sys, prompt, 768)
+	text, _, perr := parseResponseMood(resp)
+	if err != nil || perr != nil {
+		// Read the notes out rather than ship a broken fragment.
+		if perr != nil {
+			log.Printf("phraser: PhraseQuery: %v", perr)
+		}
 		if len(notes) == 1 {
 			return "вот что я нашла: " + notes[0], nil
 		}
 		return "вот что я нашла: " + strings.Join(notes, "; "), nil
 	}
-	if text, _ := parseResponseMood(resp); text != "" {
+	if text != "" {
 		return text, nil
 	}
 	return resp, nil
@@ -263,12 +278,17 @@ func (p *LLMPhraser) PhraseChat(ctx context.Context, utterance string, history [
 	combined += utterance
 	msgs = append(msgs, chatMsg{Role: "user", Content: strings.TrimSpace(combined)})
 
-	resp, err := p.chatWithMessages(ctx, msgs, 512)
+	resp, err := p.chatWithMessages(ctx, msgs, 768)
 	if err != nil {
 		log.Printf("phraser: PhraseChat: %v", err)
 		return "поговорили.", nil
 	}
-	if text, _ := parseResponseMood(resp); text != "" {
+	text, _, perr := parseResponseMood(resp)
+	if perr != nil {
+		log.Printf("phraser: PhraseChat: %v", perr)
+		return "поговорили.", nil
+	}
+	if text != "" {
 		return text, nil
 	}
 	// fallback: plain text without JSON
@@ -351,7 +371,12 @@ func (p *LLMPhraser) PhraseReminder(ctx context.Context, d loop.ReminderDecision
 	if err != nil {
 		return delivery.PhrasedReminder{}, err
 	}
-	body, mood := parseResponseMood(resp)
+	body, mood, perr := parseResponseMood(resp)
+	if perr != nil {
+		// Truncated JSON. Fall through to the reminder's own text.
+		log.Printf("phraser: PhraseReminder: %v", perr)
+		body, mood = "", ""
+	}
 	if body == "" {
 		// fallback: try old body/summary format
 		body, _ = parsePhrase(resp)
@@ -396,10 +421,16 @@ type chatReq struct {
 // Russian, so an ASCII-only rule would make every reply empty. The escape rule
 // is what lets the model close a string it opened with a quote inside. Length
 // is bounded so a repetition loop truncates the field, not the JSON object.
+//
+// That bound was 400 and 400 was too tight. Measured against Qwen3.5-0.8B: on
+// "почему гром слышно позже молнии?" the reply came back exactly 400 characters
+// long, cut mid-word ("Нужно записать и,"), at every token cap from 256 to 2048.
+// So the token cap was never what stopped it — this rule was. 1000 characters is
+// roughly six Russian sentences, still short enough to stop a repetition loop.
 const responseGrammar = `
 root   ::= "{" ws "\"response\"" ws ":" ws string ws "," ws "\"mood\"" ws ":" ws mood ws "}"
 mood   ::= "\"neutral\"" | "\"happy\"" | "\"thinking\"" | "\"tired\"" | "\"confused\""
-string ::= "\"" ([^"\\] | "\\" ["\\/bfnrt]){0,400} "\""
+string ::= "\"" ([^"\\] | "\\" ["\\/bfnrt]){0,1000} "\""
 ws     ::= [ \t\n]*
 `
 
@@ -633,21 +664,39 @@ type responseMood struct {
 	Mood     string `json:"mood"`
 }
 
+// errBrokenJSON — the model started a JSON object and never finished it.
+// That is a failed generation, not a reply. Callers must use their fallback.
+var errBrokenJSON = fmt.Errorf("phraser: model output starts as JSON but does not parse")
+
 // parseResponseMood extracts {"response","mood"} from LLM output, tolerant
-// of thinking tokens and extra text before/after the JSON block. Returns
-// ("", "") when no valid JSON is found.
-func parseResponseMood(raw string) (response, mood string) {
+// of thinking tokens and extra text before/after the JSON block.
+//
+// Three outcomes:
+//   - parsed fine → the fields, nil error.
+//   - output never looked like JSON → ("", "", nil). The caller may ship it
+//     as-is; small models sometimes answer in bare prose and that is fine.
+//   - output starts with "{" but does not parse → errBrokenJSON. The grammar
+//     guarantees a valid *prefix*, so a generation that hits the token cap
+//     mid-object comes back as a fragment like `{` or `{\n  "`. Shipping that
+//     as a reply is the bug this error exists to stop.
+func parseResponseMood(raw string) (response, mood string, err error) {
 	cleaned := strings.TrimSpace(raw)
 	start := strings.Index(cleaned, "{")
 	end := strings.LastIndex(cleaned, "}")
 	if start < 0 || end < 0 || end <= start {
-		return "", ""
+		if strings.HasPrefix(cleaned, "{") {
+			return "", "", errBrokenJSON
+		}
+		return "", "", nil
 	}
 	var parsed responseMood
-	if err := json.Unmarshal([]byte(cleaned[start:end+1]), &parsed); err != nil {
-		return "", ""
+	if e := json.Unmarshal([]byte(cleaned[start:end+1]), &parsed); e != nil {
+		if strings.HasPrefix(cleaned, "{") {
+			return "", "", errBrokenJSON
+		}
+		return "", "", nil
 	}
-	return parsed.Response, parsed.Mood
+	return parsed.Response, parsed.Mood, nil
 }
 
 func parsePhrase(raw string) (body, summary string) {