mavend: answer "а завтра?" from the previous turn, not from the model

An elliptical follow-up carries no intent of its own. followUpMerge cannot help — it inherits slots once the intent is known, and here the intent is the missing part. So "а завтра?" went to the router, which on a 1.7B is close to a coin flip, and the guess cost ~2.7s. continuationDecision runs before the router and rebuilds the turn from the previous one: same intent, same key, new day. Deterministic and free. Three guards, all narrow on purpose. A parseable date is required, which is what separates an ellipsis from an ordinary short utterance. Four tokens max. And only query, system and reminder may be inherited: fact and note would write something he did not say, and act would let a two-word utterance re-run an allowlisted fn, which is a way to fire a destructive command nobody typed. A continuation is still remembered, so "а завтра?" then "а послезавтра?" chains. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TrVSBKe3RFDF4fGYKWYQnX
2026-08-01 22:09:05 +04:00
parent d0d0021659
commit 7d08d27efb
3 changed files with 245 additions and 5 deletions
@@ -0,0 +1,118 @@
+// Elliptical follow-ups — "а завтра?" after "какие напоминания на сегодня".
+//
+// These carry no intent of their own. Two words, one of them a particle, and
+// everything that makes the utterance meaningful lives in the turn before it.
+// Sent to the router they get whatever the model guesses, which on a 1.7B is
+// close to a coin flip, and the guess costs ~2.7s to obtain.
+//
+// followUpMerge (followup.go) cannot help: it inherits SLOTS once the intent is
+// known, and here the intent is the missing part. So this runs before the
+// router and answers from the previous turn directly, which is both correct by
+// construction and free.
+package main
+
+import (
+	"time"
+
+	"github.com/kami/maven/internal/dialogue"
+	"github.com/kami/maven/internal/router"
+)
+
+// continuationMaxTokens — an ellipsis is short by definition. Past four tokens
+// the utterance carries enough of its own content to be routed on its merits,
+// and inheriting an intent for it would be overreach.
+const continuationMaxTokens = 4
+
+// continuationParticles — the words that open a follow-up. A leading particle
+// is one of the two ways in; the other is an utterance that is nothing but a
+// date ("завтра?").
+var continuationParticles = map[string]bool{
+	"а": true, "и": true, "ну": true,
+	"what": true, "and": true, "how": true,
+}
+
+// continuableIntents — which intents an ellipsis may inherit.
+//
+// query and system are questions: asking the same question about a different
+// day is exactly what "а завтра?" means. reminder is an instruction that names
+// a time, so re-aiming it at another day is a coherent second instruction.
+//
+// The rest are excluded on purpose. fact and note would write something he did
+// not say — "поужинал" then "а вчера?" is a question about yesterday, not a
+// claim about it. chat has no slot to re-aim. act is the dangerous one: an
+// allowlisted fn inherited by a two-word utterance is a way to run a
+// destructive command nobody typed, and no follow-up is worth that.
+var continuableIntents = map[dialogue.Intent]bool{
+	dialogue.IntentQuery:    true,
+	dialogue.IntentSystem:   true,
+	dialogue.IntentReminder: true,
+}
+
+// continuationDecision reads an utterance as "the previous question, but for
+// this other day". Returns ok=false whenever anything is uncertain, which
+// hands the turn back to the ordinary router path.
+//
+// The date is what makes this safe. An ellipsis with no parseable day is just
+// a short utterance, and short utterances are the router's job.
+func continuationDecision(prev *dialogue.Session, text string, now time.Time) (router.Decision, bool) {
+	if prev == nil || prev.IsExpired(now) || !continuableIntents[prev.Intent] {
+		return router.Decision{}, false
+	}
+	tokens := quietTokens(text)
+	if len(tokens) == 0 || len(tokens) > continuationMaxTokens {
+		return router.Decision{}, false
+	}
+	day, ok := router.ParseCalendarDate(text, now)
+	if !ok {
+		return router.Decision{}, false
+	}
+	// Either it opens with a particle, or the whole utterance is the date.
+	if !continuationParticles[tokens[0]] && !isBareDate(tokens, day, now) {
+		return router.Decision{}, false
+	}
+
+	dec := router.Decision{
+		Utterance:  text,
+		Intent:     router.Intent(prev.Intent),
+		Confidence: 1.0,
+		Stage:      0,
+		Slots: router.Slots{
+			Key:    prev.Slots.Key,
+			HasKey: prev.Slots.HasKey,
+			Value:  prev.Slots.Value,
+			Text:   prev.Slots.Text,
+			// Fn/Args are deliberately not carried: continuableIntents
+			// excludes act, so there is never one to carry.
+			Time:    day,
+			HasTime: true,
+		},
+	}
+	return dec, true
+}
+
+// isBareDate reports whether the utterance is nothing but its date expression.
+// "завтра" and "на выходных" qualify; "напомни завтра" does not, because the
+// verb is content of its own and belongs to the router.
+//
+// Implemented by re-parsing each token: if every token that is not part of a
+// date expression is a preposition or a question mark's leftovers, the
+// utterance is bare. Cheap enough at four tokens.
+func isBareDate(tokens []string, day time.Time, now time.Time) bool {
+	for _, t := range tokens {
+		if continuationFillers[t] {
+			continue
+		}
+		if d, ok := router.ParseCalendarDate(t, now); ok && d.Equal(day) {
+			continue
+		}
+		return false
+	}
+	return true
+}
+
+// continuationFillers — tokens that carry no content of their own inside a
+// date expression ("на выходных", "в среду").
+var continuationFillers = map[string]bool{
+	"на": true, "в": true, "во": true, "за": true, "про": true,
+	"about": true, "on": true, "for": true,
+}
@@ -0,0 +1,100 @@
+package main
+
+import (
+	"testing"
+	"time"
+
+	"github.com/kami/maven/internal/dialogue"
+	"github.com/kami/maven/internal/router"
+)
+
+var contNow = time.Date(2026, 8, 1, 12, 0, 0, 0, time.UTC)
+
+func contSession(intent dialogue.Intent, key string) *dialogue.Session {
+	return &dialogue.Session{
+		Intent:    intent,
+		Slots:     dialogue.Slots{Key: key, HasKey: key != "", Text: "какие напоминания на сегодня"},
+		Timestamp: contNow.Add(-30 * time.Second),
+		TTL:       2 * time.Minute,
+	}
+}
+
+func TestContinuationInheritsTheQuestion(t *testing.T) {
+	prev := contSession(dialogue.IntentQuery, "water")
+	dec, ok := continuationDecision(prev, "а завтра?", contNow)
+	if !ok {
+		t.Fatal("continuationDecision returned false, want a decision")
+	}
+	if dec.Intent != router.IntentQuery {
+		t.Errorf("intent = %q, want query", dec.Intent)
+	}
+	if dec.Slots.Key != "water" || !dec.Slots.HasKey {
+		t.Errorf("key = %q, want water carried over", dec.Slots.Key)
+	}
+	if !dec.Slots.HasTime {
+		t.Fatal("no time slot; the whole point is re-aiming the day")
+	}
+	if got, want := dec.Slots.Time.Format("2006-01-02"), "2026-08-02"; got != want {
+		t.Errorf("time = %s, want %s", got, want)
+	}
+}
+
+func TestContinuationAcceptsABareDate(t *testing.T) {
+	prev := contSession(dialogue.IntentQuery, "water")
+	for _, s := range []string{"завтра?", "вчера", "а вчера?", "и завтра"} {
+		if _, ok := continuationDecision(prev, s, contNow); !ok {
+			t.Errorf("continuationDecision(%q) = false, want true", s)
+		}
+	}
+}
+
+func TestContinuationDeclinesWhatIsNotAnEllipsis(t *testing.T) {
+	prev := contSession(dialogue.IntentQuery, "water")
+	for _, s := range []string{
+		// No date to re-aim at — an ordinary short utterance, the router's job.
+		"а что там", "а бэкап?", "привет", "",
+		// Content of its own: the verb is not an ellipsis.
+		"напомни завтра позвонить маме",
+		// Too long to be an ellipsis even with a date in it.
+		"а что у меня стоит в календаре на завтра",
+	} {
+		if _, ok := continuationDecision(prev, s, contNow); ok {
+			t.Errorf("continuationDecision(%q) = true, want false", s)
+		}
+	}
+}
+
+func TestContinuationDeclinesUncontinuableIntents(t *testing.T) {
+	// act is the one that matters: inheriting an allowlisted fn from a
+	// two-word utterance would be a way to run a destructive command.
+	for _, in := range []dialogue.Intent{
+		dialogue.IntentAct, dialogue.IntentFact, dialogue.IntentNote, dialogue.IntentChat,
+	} {
+		if _, ok := continuationDecision(contSession(in, "water"), "а завтра?", contNow); ok {
+			t.Errorf("continuationDecision inherited intent %q, want refusal", in)
+		}
+	}
+}
+
+func TestContinuationDeclinesWithoutALiveSession(t *testing.T) {
+	if _, ok := continuationDecision(nil, "а завтра?", contNow); ok {
+		t.Error("continued with no previous turn")
+	}
+	stale := contSession(dialogue.IntentQuery, "water")
+	stale.Timestamp = contNow.Add(-10 * time.Minute)
+	if _, ok := continuationDecision(stale, "а завтра?", contNow); ok {
+		t.Error("continued an expired session")
+	}
+}
+
+func TestContinuationNeverCarriesAnFn(t *testing.T) {
+	prev := contSession(dialogue.IntentQuery, "water")
+	prev.Slots.Fn, prev.Slots.HasFn = "restart", true
+	dec, ok := continuationDecision(prev, "а завтра?", contNow)
+	if !ok {
+		t.Fatal("want a decision")
+	}
+	if dec.Slots.HasFn || dec.Slots.Fn != "" {
+		t.Fatalf("carried fn %q into a continuation", dec.Slots.Fn)
+	}
+}
@@ -265,8 +265,27 @@ func (h *reactiveHandler) runTurn(ctx context.Context, text string, src turnSour
 		return withNotice(expiredNotice, reply)
 	}

-	// 5. router — classify the utterance.
-	dec, err := h.router.Route(ctx, text, h.now())
+	// 5. route. An elliptical follow-up — "а завтра?" — is answered from the
+	// previous turn instead (continuation.go): the intent is the part it is
+	// missing, so no amount of routing recovers it, and the model's guess
+	// costs seconds to obtain and is close to a coin flip. Everything else
+	// goes to the router.
+	var (
+		dec  router.Decision
+		err  error
+		prev *dialogue.Session
+	)
+	now := h.now()
+	if h.dialogueSessions != nil {
+		prev = h.dialogueSessions.Get(voiceDialogueID, now)
+	}
+	cont := false
+	if dec, cont = continuationDecision(prev, text, now); cont {
+		log.Printf("voice: continuation of %s from the previous turn", dec.Intent)
+	}
+	if !cont {
+		dec, err = h.router.Route(ctx, text, now)
+	}
 	if err != nil {
 		// ErrNoIntents ⇒ classifier unseeded (cold boot). reply with a
 		// "still warming up" rather than a wire error.
@@ -282,10 +301,13 @@ func (h *reactiveHandler) runTurn(ctx context.Context, text string, src turnSour
 	// turn (follow-ups like «напомни завтра» → «…позвонить маме»), then remember
 	// this turn for the next follow-up. Only same-intent, non-expired, non-
 	// clarify turns carry (see followUpMerge). Best-effort: nil store ⇒ skipped.
+	// A continuation already carries the previous turn's slots, so there is
+	// nothing left to inherit — but it is still remembered, so a chain of them
+	// ("а завтра?" … "а послезавтра?") keeps working.
 	if h.dialogueSessions != nil {
-		now := h.now()
-		prev := h.dialogueSessions.Get(voiceDialogueID, now)
-		dec = followUpMerge(prev, dec, now)
+		if !cont {
+			dec = followUpMerge(prev, dec, now)
+		}
 		if !dec.Clarify {
 			h.rememberTurn(prev, dec, now)
 		}