cmd/mavwaked/main.go

@@ -12,10 +12,12 @@
 // samples and the capture frame is 480, so silero.go re-chunks. This comment
 // used to say the two matched, which was true of silero v4.
 //
-// There is still no wake-word model, so anything spoken near the microphone
-// becomes a turn (V-487 stage two). The SurfaceVoice auth layer caps all
-// commands at L0 (no destructive acts), which is what makes an accidental
-// trigger safe rather than expensive.
+// The keyword is "Мэйвен" and it is required, when -wake-model points at the
+// head (V-487 stage two). Without it anything spoken near the microphone
+// becomes a turn, which the SurfaceVoice auth layer makes safe rather than
+// expensive: it caps all commands at L0, no destructive acts. It does not cap
+// reading, so an open gate still lets the room hear his facts read back.
+// wakeword.go holds the cadence and wakefeatures.go the three models.
 //
 // The conn carries both directions. mavwaked sends utterances and receives
 // proactive nudges on it, and it is opened at startup rather than at the first
@@ -62,6 +64,12 @@ const (
 	defaultAddr     = "127.0.0.1:9100"
 	defaultLang     = "ru"
 	defaultReadSize = 4096 // max PCM bytes per read from arecord (fits multiple frames)
+
+	// defaultWakeWindowMs — how long the keyword stays good for. He says
+	// "Мэйвен" and then a sentence, and the VAD does not close the utterance
+	// until he stops, so this has to outlive the word by the length of what
+	// follows it. It is spent on dispatch: one keyword, one turn.
+	defaultWakeWindowMs = 8000
 )
 
 func main() {
@@ -86,6 +94,11 @@ func run(args []string) error {
 	vadModel := flag.String("vad-model", "", "silero-vad onnx file; empty runs the energy threshold instead")
 	vadThreshold := flag.Float64("vad-threshold", defaultSileroThreshold, "speech probability a frame must clear")
 	onnxLib := flag.String("onnx-lib", os.Getenv("MAVEN_ONNX_LIB"), "libonnxruntime.so, needed with -vad-model")
+	wakeModel := flag.String("wake-model", "", "keyword head onnx; empty ships every utterance, as before V-487")
+	wakeMel := flag.String("wake-mel", "", "melspectrogram.onnx, required with -wake-model")
+	wakeEmbed := flag.String("wake-embed", "", "embedding_model.onnx, required with -wake-model")
+	wakeThreshold := flag.Float64("wake-threshold", defaultWakeThreshold, "score the keyword must clear")
+	wakeWindowMs := flag.Int("wake-window-ms", defaultWakeWindowMs, "ms an utterance may still start after the keyword")
 	flag.CommandLine.Parse(args)
 
 	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
@@ -171,6 +184,21 @@ func run(args []string) error {
 	}
 	sess := newSession(vad, newAplayPlayer(), &voiceSender{vc: vc}, *lang, barge)
 
+	// Keyword gate. A model that will not load is logged and not fatal, for
+	// the same reason silero's is not: an open gate is the daemon he had
+	// yesterday, and a daemon that refuses to start is not.
+	if *wakeModel != "" {
+		w, err := newWakeWord(*wakeMel, *wakeEmbed, *wakeModel, *onnxLib, *wakeThreshold)
+		if err != nil {
+			log.Printf("mavwaked: wake word unavailable, every utterance is a turn: %v", err)
+		} else {
+			defer w.Close()
+			sess.UseWakeWord(w, time.Duration(*wakeWindowMs)*time.Millisecond)
+			log.Printf("mavwaked: wake word from %s, threshold %.3f, window %dms",
+				*wakeModel, *wakeThreshold, *wakeWindowMs)
+		}
+	}
+
 	// Listen for nudges alongside capture. Connect eagerly so mavend has a
 	// voice session before he has said anything: without one, a nudge routed
 	// to voice finds nobody home and goes to the away channels instead.

cmd/mavwaked/session.go

@@ -20,6 +20,15 @@ type utteranceSender interface {
 	Send(ctx context.Context, utt audio.Audio, lang string) (audio.Audio, error)
 }
 
+// keywordGate answers whether the keyword has just been spoken. The
+// production one is wakeWord; tests substitute a recorder, because a gate that
+// can only be exercised with three ONNX files is a gate nobody tests.
+type keywordGate interface {
+	Feed(frame []int16) bool
+	Reset()
+	Score() float64
+}
+
 // bargeInConfig holds the two numbers barge-in needs. Zero Frames disables
 // barge-in entirely — the half-duplex gate still runs.
 type bargeInConfig struct {
@@ -63,6 +72,14 @@ type session struct {
 	// whenever playback ends.
 	loudFrames int
 
+	// wake is the keyword gate, or nil when no model was loaded. wakeUntil is
+	// how long a keyword stays good for: he says "Мэйвен" and then a sentence,
+	// and the VAD does not close the utterance until he stops, so the window
+	// has to outlive the word by the length of what follows it.
+	wake       keywordGate
+	wakeWindow time.Duration
+	wakeUntil  time.Time
+
 	// pending holds a nudge the push receiver handed over, waiting for the
 	// capture loop to speak it. It is the one field written from another
 	// goroutine, hence the mutex; everything else in this struct belongs to
@@ -76,6 +93,8 @@ type session struct {
 	bargeIns   int // times playback was cut because he spoke over her
 	sent       int // utterances shipped to the daemon
 	nudges     int // proactive pushes spoken through the speaker
+	wakes      int // times the keyword opened the gate
+	ignored    int // complete utterances dropped because the keyword was absent
 
 	// loudSum and loudSeen accumulate the energy of suppressed frames, so
 	// the operator can read what the room actually measures and set
@@ -88,6 +107,12 @@ func newSession(vad *VAD, p player, s utteranceSender, lang string, barge bargeI
 	return &session{vad: vad, player: p, sender: s, lang: lang, barge: barge, now: time.Now}
 }
 
+// UseWakeWord puts the keyword gate in front of dispatch. Without it every
+// utterance is shipped, which is what mavwaked did before V-487 stage two.
+func (s *session) UseWakeWord(w keywordGate, window time.Duration) {
+	s.wake, s.wakeWindow = w, window
+}
+
 // frameDuration is the wall time one captured frame represents.
 const frameDuration = defaultFrameMs * time.Millisecond
 
@@ -147,6 +172,7 @@ func (s *session) feed(ctx context.Context, frame []byte) error {
 		s.bargeIns++
 		s.loudFrames = 0
 		s.vad.Reset()
+		s.resetWake()
 		log.Printf("mavwaked: barge-in — stopped playback")
 		s.replayRecent()
 		return nil
@@ -157,13 +183,28 @@ func (s *session) feed(ctx context.Context, frame []byte) error {
 	if s.loudFrames != 0 {
 		s.loudFrames = 0
 		s.vad.Reset()
+		// The wake word saw nothing during playback, so what it holds is from
+		// before she spoke. Judging what he says next on it would score a
+		// sentence that ended a reply ago.
+		s.resetWake()
 	}
 
 	if s.startPendingNudge() {
 		return nil
 	}
 
-	utt, state := s.vad.Feed(PCMToI16(frame))
+	// The keyword is scored on the same frames the VAD sees, and only on the
+	// ones that reach here: every path above returns while she is speaking, so
+	// her own voice saying "Мэйвен" cannot wake her.
+	pcm := PCMToI16(frame)
+	if s.wake != nil && s.wake.Feed(pcm) {
+		s.wakes++
+		s.wakeUntil = s.now().Add(s.wakeWindow)
+		log.Printf("mavwaked: keyword heard (score %.3f), listening for %s",
+			s.wake.Score(), s.wakeWindow)
+	}
+
+	utt, state := s.vad.Feed(pcm)
 	if state == StateSpeech || utt.Bytes == nil {
 		return nil
 	}
@@ -218,6 +259,25 @@ func (s *session) startPendingNudge() bool {
 	return true
 }
 
+// awake reports whether an utterance ending now was addressed to her.
+//
+// With no wake word loaded every utterance is, which is exactly what mavwaked
+// did before this gate existed. An operator with no model file gets the old
+// daemon rather than a daemon that refuses to hear anything.
+func (s *session) awake() bool {
+	if s.wake == nil {
+		return true
+	}
+	return s.now().Before(s.wakeUntil)
+}
+
+// resetWake drops the gate's streaming state when there is a gate.
+func (s *session) resetWake() {
+	if s.wake != nil {
+		s.wake.Reset()
+	}
+}
+
 // keepRecent stores a copy of one barge-in trigger frame, keeping at most
 // barge.Frames of them.
 func (s *session) keepRecent(frame []byte) {
@@ -258,6 +318,19 @@ func (s *session) replayRecent() {
 // whole backlog straight into the VAD, and a Send error did the same on every
 // failed turn, so a dead socket drove a retry loop off nothing but backlog.
 func (s *session) dispatch(ctx context.Context, utt audio.Audio) error {
+	if !s.awake() {
+		s.ignored++
+		log.Printf("mavwaked: utterance ignored, keyword not heard (%.2fs, %d ignored so far)",
+			utt.Duration(), s.ignored)
+		s.vad.Reset()
+		s.resetWake()
+		return nil
+	}
+	// One keyword, one turn. A window that renewed itself on every reply would
+	// leave the microphone open for as long as he kept talking, which is the
+	// state this gate exists to end.
+	s.wakeUntil = time.Time{}
+
 	log.Printf("mavwaked: utterance complete (%.2fs, %d bytes), sending...", utt.Duration(), len(utt.Bytes))
 	start := s.now()
 	reply, err := s.sender.Send(ctx, utt, s.lang)
@@ -286,6 +359,7 @@ func (s *session) dispatch(ctx context.Context, utt audio.Audio) error {
 // recorded before she started speaking.
 func (s *session) dropBacklog(start time.Time) {
 	s.vad.Reset()
+	s.resetWake()
 	s.loudFrames = 0
 	s.recent = s.recent[:0]
 	if elapsed := s.now().Sub(start); elapsed > 0 {

cmd/mavwaked/wakefeatures.go

@@ -0,0 +1,187 @@
+package main
+
+// The three models behind the wake word (V-487 stage two).
+//
+// openWakeWord's pipeline, run in a row:
+//
+//	audio      -> melspectrogram.onnx -> 32-bin mel frames, one per 10ms
+//	76 frames  -> embedding_model.onnx -> one 96-dim embedding per 80ms
+//	16 embeds  -> maven_wakeword.onnx  -> one score
+//
+// The first two are frozen and pretrained. Only the last was trained here,
+// which is why it is 100KB and the other two are megabytes. The shapes are
+// not guesses: 2.0s of 16kHz audio measures 197 mel frames, and 76-frame
+// windows at stride 8 give exactly the 16 embeddings the head was fitted on.
+//
+// This file knows ONNX and nothing about the 80ms cadence. wakeword.go knows
+// the cadence and nothing about tensors.
+
+import (
+	"fmt"
+
+	ort "github.com/yalue/onnxruntime_go"
+)
+
+const (
+	// melHop — samples per mel frame. 10ms at 16kHz.
+	melHop = 160
+	// melBins — mel bins per frame, fixed by melspectrogram.onnx.
+	melBins = 32
+	// embedFrames — mel frames one embedding is computed over, 760ms.
+	embedFrames = 76
+	// embedStride — mel frames between embeddings, 80ms.
+	embedStride = 8
+	// embedDim — the embedding width.
+	embedDim = 96
+	// headWindow — embeddings the head scores at once, 1.28s of audio.
+	headWindow = 16
+
+	// melContext — samples of history prepended to each incremental mel
+	// call, chosen so the eight frames this call yields continue exactly
+	// where the previous call's eight stopped.
+	//
+	// melspectrogram.onnx returns N/160-3 frames for N samples, and frame i
+	// covers [i*160, i*160+400). With 480 samples of history the buffer is
+	// 1760 samples, which is 8 frames, and the oldest of them starts one hop
+	// after the newest of the previous call. Less history leaves a gap: the
+	// first frames of a bare chunk would be computed against silence.
+	melContext = 480
+
+	// chunkSamples — audio per embedding step, 80ms.
+	chunkSamples = embedStride * melHop
+)
+
+// wakeModels holds the three ONNX sessions. It runs on CPU threads beside
+// silero and never touches the GPU. That is a rule, not a result: a wake word
+// that waits on card admission is not a wake word.
+type wakeModels struct {
+	mel  *ort.DynamicAdvancedSession
+	emb  *ort.DynamicAdvancedSession
+	head *ort.DynamicAdvancedSession
+}
+
+// newWakeModels loads all three. melPath and embedPath are openWakeWord's
+// frozen feature models; headPath is the keyword head trained for "Мэйвен".
+func newWakeModels(melPath, embedPath, headPath, libPath string) (*wakeModels, error) {
+	if !ort.IsInitialized() {
+		if libPath != "" {
+			ort.SetSharedLibraryPath(libPath)
+		}
+		if err := ort.InitializeEnvironment(); err != nil {
+			return nil, fmt.Errorf("wake word: onnx runtime: %w", err)
+		}
+	}
+	open := func(p string, in, out []string) (*ort.DynamicAdvancedSession, error) {
+		s, err := ort.NewDynamicAdvancedSession(p, in, out, nil)
+		if err != nil {
+			return nil, fmt.Errorf("wake word: load %s: %w", p, err)
+		}
+		return s, nil
+	}
+	m := &wakeModels{}
+	var err error
+	if m.mel, err = open(melPath, []string{"input"}, []string{"output"}); err != nil {
+		return nil, err
+	}
+	if m.emb, err = open(embedPath, []string{"input_1"}, []string{"conv2d_19"}); err != nil {
+		m.Close()
+		return nil, err
+	}
+	if m.head, err = open(headPath, []string{"embeddings"}, []string{"score"}); err != nil {
+		m.Close()
+		return nil, err
+	}
+	return m, nil
+}
+
+// Close releases the three sessions.
+func (m *wakeModels) Close() {
+	if m == nil {
+		return
+	}
+	for _, s := range []*ort.DynamicAdvancedSession{m.mel, m.emb, m.head} {
+		if s != nil {
+			s.Destroy()
+		}
+	}
+	m.mel, m.emb, m.head = nil, nil, nil
+}
+
+// melFrames runs one buffer of samples and returns the mel frames it yielded.
+func (m *wakeModels) melFrames(buf []float32) ([][melBins]float32, error) {
+	in, err := ort.NewTensor(ort.NewShape(1, int64(len(buf))), buf)
+	if err != nil {
+		return nil, err
+	}
+	defer in.Destroy()
+
+	n := int64(len(buf)/melHop - 3)
+	if n < 1 {
+		return nil, fmt.Errorf("wake word: %d samples yield no mel frames", len(buf))
+	}
+	out, err := ort.NewEmptyTensor[float32](ort.NewShape(1, 1, n, melBins))
+	if err != nil {
+		return nil, err
+	}
+	defer out.Destroy()
+
+	if err := m.mel.Run([]ort.Value{in}, []ort.Value{out}); err != nil {
+		return nil, err
+	}
+	data := out.GetData()
+	frames := make([][melBins]float32, n)
+	for i := range frames {
+		for j := 0; j < melBins; j++ {
+			// The scaling openWakeWord applies between the two feature
+			// models, and the head was fitted on its output.
+			frames[i][j] = data[i*melBins+j]/10.0 + 2.0
+		}
+	}
+	return frames, nil
+}
+
+// embedding runs embedFrames mel frames through the frozen embedder.
+func (m *wakeModels) embedding(mels [][melBins]float32) ([embedDim]float32, error) {
+	var e [embedDim]float32
+	flat := make([]float32, 0, embedFrames*melBins)
+	for _, f := range mels {
+		flat = append(flat, f[:]...)
+	}
+	in, err := ort.NewTensor(ort.NewShape(1, embedFrames, melBins, 1), flat)
+	if err != nil {
+		return e, err
+	}
+	defer in.Destroy()
+	out, err := ort.NewEmptyTensor[float32](ort.NewShape(1, 1, 1, embedDim))
+	if err != nil {
+		return e, err
+	}
+	defer out.Destroy()
+	if err := m.emb.Run([]ort.Value{in}, []ort.Value{out}); err != nil {
+		return e, err
+	}
+	copy(e[:], out.GetData())
+	return e, nil
+}
+
+// score runs the trained head over headWindow embeddings.
+func (m *wakeModels) score(embeds [][embedDim]float32) (float64, error) {
+	flat := make([]float32, 0, headWindow*embedDim)
+	for _, e := range embeds {
+		flat = append(flat, e[:]...)
+	}
+	in, err := ort.NewTensor(ort.NewShape(1, headWindow, embedDim), flat)
+	if err != nil {
+		return 0, err
+	}
+	defer in.Destroy()
+	out, err := ort.NewEmptyTensor[float32](ort.NewShape(1, 1))
+	if err != nil {
+		return 0, err
+	}
+	defer out.Destroy()
+	if err := m.head.Run([]ort.Value{in}, []ort.Value{out}); err != nil {
+		return 0, err
+	}
+	return float64(out.GetData()[0]), nil
+}

cmd/mavwaked/wakeword.go

@@ -0,0 +1,191 @@
+package main
+
+// The wake word, "Мэйвен" (V-487 stage two).
+//
+// Silero answers "is this frame speech". It does not answer "was this said to
+// her", and until this file existed nothing did: every utterance near the
+// microphone became a turn. What made that safe rather than expensive was
+// SurfaceVoice capping acts at L0, and L0 does not cap reading, so the room
+// could still hear his facts read back.
+//
+// This file owns the 80ms cadence and the three rings of state between the
+// models. wakefeatures.go owns the tensors.
+//
+// Nil is a working value, and it is the CLOSED gate rather than the open one.
+// Feed on a nil receiver reports no keyword; session.go asks separately
+// whether a gate exists at all. That split is deliberate: a nil that answers
+// "yes, keyword" reads as a working wake word in every log line it produces.
+
+import (
+	"log"
+	"sync"
+)
+
+// defaultWakeThreshold — score above which the keyword was said. Picked from
+// the false-accept rate on held-out Russian speech, not from accuracy: a miss
+// costs him a repeat, a false accept costs a turn nobody asked for. See
+// docs/evals for the wakes-per-hour this buys.
+const defaultWakeThreshold = 0.99
+
+// wakeWord is the streaming state around wakeModels. It is fed the same
+// capture frames the VAD sees and answers whether the keyword has just been
+// spoken.
+type wakeWord struct {
+	mu sync.Mutex
+	m  *wakeModels
+
+	threshold float64
+
+	// pending holds captured samples not yet part of a full 80ms chunk, and
+	// history holds the melContext samples before them.
+	pending []float32
+	history []float32
+
+	// mels is the newest embedFrames mel frames, oldest first.
+	mels [][melBins]float32
+	// embeds is the newest headWindow embeddings, oldest first.
+	embeds [][embedDim]float32
+
+	last float64 // most recent score, held between chunks
+}
+
+// newWakeWord loads the models and wraps them in the streaming gate.
+func newWakeWord(melPath, embedPath, headPath, libPath string, threshold float64) (*wakeWord, error) {
+	m, err := newWakeModels(melPath, embedPath, headPath, libPath)
+	if err != nil {
+		return nil, err
+	}
+	if threshold <= 0 {
+		threshold = defaultWakeThreshold
+	}
+	return &wakeWord{m: m, threshold: threshold}, nil
+}
+
+// Close releases the models.
+func (w *wakeWord) Close() {
+	if w == nil {
+		return
+	}
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	w.m.Close()
+	w.m = nil
+}
+
+// Feed takes one capture frame and reports whether the keyword was heard on
+// it. A nil wakeWord hears nothing.
+func (w *wakeWord) Feed(frame []int16) bool {
+	if w == nil {
+		return false
+	}
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
+	for _, v := range frame {
+		w.pending = append(w.pending, float32(v)/32768.0)
+	}
+	fired := false
+	for len(w.pending) >= chunkSamples {
+		chunk := w.pending[:chunkSamples]
+		if w.step(chunk) {
+			fired = true
+		}
+		w.history = append(w.history[:0], tailFloat32(append(w.history, chunk...), melContext)...)
+		// Slide the remainder to the front rather than reslicing. This runs
+		// every 80ms for as long as the daemon lives.
+		w.pending = append(w.pending[:0], w.pending[chunkSamples:]...)
+	}
+	return fired
+}
+
+// Reset drops the streaming state, so a fresh utterance is not judged on audio
+// from before it. Called after every dispatch and after barge-in, for the same
+// reason silero is: echo-era history must not score the next sentence, and her
+// own voice saying the keyword must not wake her.
+func (w *wakeWord) Reset() {
+	if w == nil {
+		return
+	}
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	w.pending, w.history = w.pending[:0], w.history[:0]
+	w.mels, w.embeds = nil, nil
+	w.last = 0
+}
+
+// Score returns the most recent score, for the operator to read out of the
+// journal when picking a threshold for his room.
+func (w *wakeWord) Score() float64 {
+	if w == nil {
+		return 0
+	}
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	return w.last
+}
+
+// step runs one 80ms chunk through all three models. It returns true when the
+// score crosses the threshold on this chunk.
+func (w *wakeWord) step(chunk []float32) bool {
+	buf := make([]float32, 0, melContext+len(chunk))
+	if pad := melContext - len(w.history); pad > 0 {
+		buf = append(buf, make([]float32, pad)...)
+	}
+	buf = append(buf, tailFloat32(w.history, melContext)...)
+	buf = append(buf, chunk...)
+
+	frames, err := w.m.melFrames(buf)
+	if err != nil {
+		// A failed inference must not silence the microphone. Hold the last
+		// score and let the next chunk try again.
+		log.Printf("mavwaked: wake word: mel: %v", err)
+		return false
+	}
+	w.mels = tailMel(append(w.mels, frames...), embedFrames)
+	if len(w.mels) < embedFrames {
+		return false
+	}
+	e, err := w.m.embedding(w.mels)
+	if err != nil {
+		log.Printf("mavwaked: wake word: embedding: %v", err)
+		return false
+	}
+	w.embeds = tailEmbed(append(w.embeds, e), headWindow)
+	if len(w.embeds) < headWindow {
+		return false
+	}
+	score, err := w.m.score(w.embeds)
+	if err != nil {
+		log.Printf("mavwaked: wake word: head: %v", err)
+		return false
+	}
+	// Report the crossing, not the state. A keyword held above the threshold
+	// for a second is one wake, and firing on every chunk of it would make the
+	// gate look open when it is merely slow to fall.
+	crossed := score >= w.threshold && w.last < w.threshold
+	w.last = score
+	return crossed
+}
+
+// The three rings. Each keeps the newest n entries and nothing older.
+
+func tailFloat32(s []float32, n int) []float32 {
+	if len(s) <= n {
+		return s
+	}
+	return s[len(s)-n:]
+}
+
+func tailMel(s [][melBins]float32, n int) [][melBins]float32 {
+	if len(s) <= n {
+		return s
+	}
+	return append(s[:0], s[len(s)-n:]...)
+}
+
+func tailEmbed(s [][embedDim]float32, n int) [][embedDim]float32 {
+	if len(s) <= n {
+		return s
+	}
+	return append(s[:0], s[len(s)-n:]...)
+}

cmd/mavwaked/wakeword_test.go

@@ -0,0 +1,174 @@
+package main
+
+import (
+	"context"
+	"testing"
+	"time"
+)
+
+// fakeGate fires on demand instead of running three ONNX models. The gate's
+// own arithmetic is measured on real audio in docs/evals; what these tests
+// cover is the thing that decides whether an utterance is shipped.
+type fakeGate struct {
+	fireOn int // fire when this many frames have been fed, 0 never fires
+	fed    int
+	resets int
+}
+
+func (g *fakeGate) Feed(_ []int16) bool {
+	g.fed++
+	return g.fireOn > 0 && g.fed == g.fireOn
+}
+func (g *fakeGate) Reset()         { g.resets++ }
+func (g *fakeGate) Score() float64 { return 1 }
+
+// wakingSession wires a session whose gate fires on the first frame it sees.
+func wakingSession(fireOn int, window time.Duration) (*session, *fakePlayer, *fakeSender, *fakeGate) {
+	sess, p, snd := newTestSession(bargeInConfig{})
+	g := &fakeGate{fireOn: fireOn}
+	sess.UseWakeWord(g, window)
+	return sess, p, snd, g
+}
+
+func TestKeywordlessSpeechNeverReachesSTT(t *testing.T) {
+	sess, p, snd, g := wakingSession(0, 8*time.Second)
+	speakThenPause(t, sess)
+
+	if len(snd.sent) != 0 {
+		t.Fatalf("sent %d utterances, want 0 — this is the whole point of V-487", len(snd.sent))
+	}
+	if sess.ignored != 1 {
+		t.Errorf("ignored = %d, want 1", sess.ignored)
+	}
+	if p.plays != 0 {
+		t.Errorf("plays = %d, want 0", p.plays)
+	}
+	if g.fed == 0 {
+		t.Error("the gate was never fed a frame")
+	}
+}
+
+func TestKeywordOpensTheGate(t *testing.T) {
+	sess, p, snd, _ := wakingSession(1, 8*time.Second)
+	speakThenPause(t, sess)
+
+	if len(snd.sent) != 1 {
+		t.Fatalf("sent %d utterances, want 1", len(snd.sent))
+	}
+	if sess.wakes != 1 {
+		t.Errorf("wakes = %d, want 1", sess.wakes)
+	}
+	if sess.ignored != 0 {
+		t.Errorf("ignored = %d, want 0", sess.ignored)
+	}
+	if p.plays != 1 {
+		t.Errorf("plays = %d, want 1", p.plays)
+	}
+}
+
+// One keyword buys one turn. Without this the microphone stays open for as
+// long as he keeps talking, which is the state the gate exists to end.
+func TestOneKeywordBuysOneTurn(t *testing.T) {
+	sess, p, snd, _ := wakingSession(1, 8*time.Second)
+	speakThenPause(t, sess)
+	p.Stop()         // she finished her reply
+	sess.discard = 0 // the backlog drain is not what this measures
+	speakThenPause(t, sess)
+
+	if len(snd.sent) != 1 {
+		t.Fatalf("sent %d utterances, want 1: the second had no keyword", len(snd.sent))
+	}
+	if sess.ignored != 1 {
+		t.Errorf("ignored = %d, want 1", sess.ignored)
+	}
+}
+
+// The keyword is heard, then he says nothing for longer than the window. What
+// he says after that is not addressed to her.
+func TestTheKeywordExpires(t *testing.T) {
+	sess, _, snd, _ := wakingSession(1, 500*time.Millisecond)
+	now := time.Unix(1750000000, 0)
+	sess.now = func() time.Time { return now }
+
+	if err := sess.feed(context.Background(), silentBytes()); err != nil {
+		t.Fatalf("feed: %v", err)
+	}
+	if sess.wakes != 1 {
+		t.Fatalf("wakes = %d, want 1", sess.wakes)
+	}
+	now = now.Add(2 * time.Second)
+	speakThenPause(t, sess)
+
+	if len(snd.sent) != 0 {
+		t.Fatalf("sent %d utterances, want 0 — the keyword had expired", len(snd.sent))
+	}
+}
+
+// Barge-in cuts her off whether or not the keyword was heard. What he says
+// after cutting her off still has to carry it.
+func TestBargeInStillInterruptsHer(t *testing.T) {
+	sess, p, _, g := wakingSession(0, 8*time.Second)
+	sess.barge = bargeInConfig{RMS: 0.2, Frames: 3}
+	p.playing = true
+	loud := frameAt(0.35)
+	for i := 0; i < 4; i++ {
+		if err := sess.feed(context.Background(), loud); err != nil {
+			t.Fatalf("feed %d: %v", i, err)
+		}
+	}
+	if sess.bargeIns != 1 {
+		t.Fatalf("bargeIns = %d, want 1", sess.bargeIns)
+	}
+	if p.stops != 1 {
+		t.Errorf("stops = %d, want 1", p.stops)
+	}
+	if g.resets == 0 {
+		t.Error("barge-in left pre-playback audio in the gate")
+	}
+}
+
+// Her own reply must not wake her. Frames captured while the player runs never
+// reach the gate, and the gate is cleared when playback ends.
+func TestHerOwnVoiceNeverReachesTheGate(t *testing.T) {
+	sess, p, _, g := wakingSession(1, 8*time.Second)
+	p.playing = true
+	for i := 0; i < 10; i++ {
+		if err := sess.feed(context.Background(), frameAt(0.35)); err != nil {
+			t.Fatalf("feed: %v", err)
+		}
+	}
+	if g.fed != 0 {
+		t.Fatalf("gate was fed %d frames while she was speaking, want 0", g.fed)
+	}
+	if sess.wakes != 0 {
+		t.Errorf("wakes = %d, want 0", sess.wakes)
+	}
+}
+
+// No model, no gate: the daemon behaves exactly as it did before V-487 stage
+// two. An operator with a missing file gets yesterday's mavwaked, not one that
+// refuses to hear anything.
+func TestNoGateShipsEveryUtterance(t *testing.T) {
+	sess, _, snd := newTestSession(bargeInConfig{})
+	speakThenPause(t, sess)
+
+	if len(snd.sent) != 1 {
+		t.Fatalf("sent %d utterances, want 1", len(snd.sent))
+	}
+	if sess.ignored != 0 {
+		t.Errorf("ignored = %d, want 0", sess.ignored)
+	}
+}
+
+// A nil *wakeWord is the closed gate, not a crash and not an open one.
+func TestNilWakeWordHearsNothing(t *testing.T) {
+	var w *wakeWord
+	if w.Feed([]int16{0, 0, 0}) {
+		t.Error("a nil wake word reported the keyword")
+	}
+	if w.Score() != 0 {
+		t.Error("a nil wake word reported a score")
+	}
+	w.Reset()
+	w.Close()
+}