Fix active speech ending on background noise

docs/TURN_TAKING_STATE_MACHINE.md

@@ -105,10 +105,10 @@ Required fields: `mode`, `speechThreshold`, `noiseFloorThreshold`, `minSpeechMs`
 ### VAD/open microphone
 
 - `armed` + qualifying speech -> `user_speaking`
-- `armed` + level below `speechThreshold` but above `noiseFloorThreshold` -> `noise_gated`
+- `armed` + level below `speechThreshold` but at or above `noiseFloorThreshold` -> `noise_gated`
 - `noise_gated` + qualifying speech -> `user_speaking`
-- `user_speaking` + silence for `silenceMs` -> `cooldown`
-- `cooldown` after `cooldownMs` -> `armed`
+- `user_speaking` + level below `speechThreshold` for `silenceMs` -> `cooldown` (the idle noise floor does not extend an active utterance)
+- after `cooldownMs`, the next input is evaluated normally from the open-microphone gate
 
 ### Wake-hook
 

src/core.js

@@ -271,19 +271,6 @@ export class BargeKitEngine {
       return this.getSnapshot();
     }
 
-    if (normalized.level >= this.config.noiseFloorThreshold) {
-      this.candidateSpeech = null;
-      this.emitter.emit('bargekit.input.noise_gated', {
-        type: 'bargekit.input.noise_gated',
-        timestamp,
-        level: normalized.level
-      });
-      if (!this.activeSpeech) {
-        this.#setState('noise_gated', timestamp, 'mic.level');
-      }
-      return this.getSnapshot();
-    }
-
     this.candidateSpeech = null;
     if (this.activeSpeech) {
       if (this.lastBelowThresholdAt === 0) {
@@ -299,6 +286,16 @@ export class BargeKitEngine {
       return this.getSnapshot();
     }
 
+    if (normalized.level >= this.config.noiseFloorThreshold) {
+      this.emitter.emit('bargekit.input.noise_gated', {
+        type: 'bargekit.input.noise_gated',
+        timestamp,
+        level: normalized.level
+      });
+      this.#setState('noise_gated', timestamp, 'mic.level');
+      return this.getSnapshot();
+    }
+
     if (!this.agentOutputActive) {
       this.#setState('listening', timestamp, 'mic.level');
     }

test/core-state-engine.test.js

@@ -56,6 +56,38 @@ test('engine noise-gates keyboard-like bursts below speech threshold', () => {
   assert.ok(events.every((event) => event.level >= 0.18 && event.level < 0.6));
 });
 
+test('active speech ends after sustained sub-speech noise at the noise floor', () => {
+  const engine = createBargeKit({
+    mode: 'vad',
+    speechThreshold: 0.5,
+    noiseFloorThreshold: 0.1,
+    minSpeechMs: 20,
+    debounceMs: 20,
+    silenceMs: 100,
+    cooldownMs: 40
+  });
+  const ends = collect(engine, 'bargekit.user_speech.ended');
+
+  engine.start(0);
+  engine.ingestLevel({ timestamp: 0, level: 0.8 });
+  engine.ingestLevel({ timestamp: 20, level: 0.8 });
+  engine.ingestLevel({ timestamp: 80, level: 0.2 });
+  engine.ingestLevel({ timestamp: 180, level: 0.2 });
+
+  assert.equal(ends.length, 1);
+  assert.equal(ends[0].reason, 'vad.speech.end');
+  assert.equal(ends[0].endedAt, 180);
+  assert.equal(engine.getSnapshot().state, 'cooldown');
+
+  engine.ingestLevel({ timestamp: 200, level: 0.2 });
+  assert.equal(ends.length, 1);
+  assert.equal(engine.getSnapshot().state, 'cooldown');
+
+  engine.ingestLevel({ timestamp: 220, level: 0.05 });
+  assert.equal(ends.length, 1);
+  assert.equal(engine.getSnapshot().state, 'listening');
+});
+
 test('push-to-talk mode ignores speech until push is held', () => {
   const engine = createBargeKit({ mode: 'push_to_talk', minSpeechMs: 80, debounceMs: 40 });
   const starts = collect(engine, 'bargekit.user_speech.started');