Merge branch 'main' into fix/fd_1828

lib/session/call-info.js

@@ -12,7 +12,6 @@ class CallInfo {
     let srf;
     this.direction = opts.direction;
     this.traceId = opts.traceId;
-    this.hasRecording = false;
     this.callTerminationBy = undefined;
     if (opts.req) {
       const u = opts.req.getParsedHeader('from');

lib/session/call-session.js

@@ -756,101 +756,69 @@ class CallSession extends Emitter {
     return this._fillerNoise;
   }
 
+  async pauseOrResumeBackgroundListenIfRequired(action, silence = false) {
+    if ((action == 'pauseCallRecording' || action == 'resumeCallRecording') &&
+    this.backgroundTaskManager.isTaskRunning('record')) {
+      this.logger.debug({action, silence}, 'CallSession:pauseOrResumeBackgroundListenIfRequired');
+      const backgroundListenTask = this.backgroundTaskManager.getTask('record');
+      const status = action === 'pauseCallRecording' ? ListenStatus.Pause : ListenStatus.Resume;
+      backgroundListenTask.updateListen(
+        status,
+        silence
+      );
+    }
+  }
 
   async notifyRecordOptions(opts) {
-    const {action, silence = false, type = 'siprec'} = opts;
+    const {action, silence} = opts;
     this.logger.debug({opts}, 'CallSession:notifyRecordOptions');
 
-    if (type == 'cloud') {
-      switch (action) {
-        case 'pauseCallRecording':
-          if (this.backgroundTaskManager.isTaskRunning('record')) {
-            this.logger.debug({action, silence, type}, 'CallSession:cloudRecording');
-            const backgroundListenTask = this.backgroundTaskManager.getTask('record');
-            backgroundListenTask.updateListen(
-              ListenStatus.Pause,
-              silence
-            );
-            return true;
-          } else { return false; }
-        case 'resumeCallRecording':
-          if (this.backgroundTaskManager.isTaskRunning('record')) {
-            this.logger.debug({action, silence, type}, 'CallSession:cloudRecording');
-            const backgroundListenTask = this.backgroundTaskManager.getTask('record');
-            backgroundListenTask.updateListen(
-              ListenStatus.Resume,
-              silence
-            );
-            return true;
-          } else { return false; }
-        case 'startCallRecording':
-          if (!this.backgroundTaskManager.isTaskRunning('record')) {
-            this.logger.debug({action, silence, type}, 'CallSession:cloudRecording');
-            this.callInfo.hasRecording = true;
-            this.updateCallStatus(Object.assign({}, this.callInfo.toJSON()), this.serviceUrl)
-              .catch((err) => this.logger.error(err, 'redis error'));
-            if (!this.dlg) {
-              // Call not yet answered so set flag to record on status change
-              this.application.record_all_calls = true;
-            } else {
-              this.backgroundTaskManager.newTask('record');
-            }
-            return true;
-          } else { return false; }
-        case 'stopCallRecording':
-          if (this.backgroundTaskManager.isTaskRunning('record')) {
-            this.logger.debug({action, silence, type}, 'CallSession:cloudRecording');
-            this.backgroundTaskManager.stop('record');
-            return true;
-          } else { return false; }
-      }
-    } else {
-      // SIPREC
-      /* if we have not answered yet, just save the details for later */
-      if (!this.dlg) {
-        if (action === 'startCallRecording') {
-          this.recordOptions = opts;
-          return true;
-        }
-        return false;
-      }
+    this.pauseOrResumeBackgroundListenIfRequired(action, silence);
 
-      /* check validity of request */
-      if (action == 'startCallRecording' && this.recordState !== RecordState.RecordingOff) {
-        this.logger.info({recordState: this.recordState},
-          'CallSession:notifyRecordOptions: recording is already started, ignoring request');
-        return false;
-      }
-      if (action == 'stopCallRecording' && this.recordState === RecordState.RecordingOff) {
-        this.logger.info({recordState: this.recordState},
-          'CallSession:notifyRecordOptions: recording is already stopped, ignoring request');
-        return false;
-      }
-      if (action == 'pauseCallRecording' && this.recordState !== RecordState.RecordingOn) {
-        this.logger.info({recordState: this.recordState},
-          'CallSession:notifyRecordOptions: cannot pause recording, ignoring request ');
-        return false;
-      }
-      if (action == 'resumeCallRecording' && this.recordState !== RecordState.RecordingPaused) {
-        this.logger.info({recordState: this.recordState},
-          'CallSession:notifyRecordOptions: cannot resume recording, ignoring request ');
-        return false;
+    /* if we have not answered yet, just save the details for later */
+    if (!this.dlg) {
+      if (action === 'startCallRecording') {
+        this.recordOptions = opts;
+        return true;
       }
+      return false;
+    }
 
-      this.recordOptions = opts;
+    /* check validity of request */
+    if (action == 'startCallRecording' && this.recordState !== RecordState.RecordingOff) {
+      this.logger.info({recordState: this.recordState},
+        'CallSession:notifyRecordOptions: recording is already started, ignoring request');
+      return false;
+    }
+    if (action == 'stopCallRecording' && this.recordState === RecordState.RecordingOff) {
+      this.logger.info({recordState: this.recordState},
+        'CallSession:notifyRecordOptions: recording is already stopped, ignoring request');
+      return false;
+    }
+    if (action == 'pauseCallRecording' && this.recordState !== RecordState.RecordingOn) {
+      this.logger.info({recordState: this.recordState},
+        'CallSession:notifyRecordOptions: cannot pause recording, ignoring request ');
+      return false;
+    }
+    if (action == 'resumeCallRecording' && this.recordState !== RecordState.RecordingPaused) {
+      this.logger.info({recordState: this.recordState},
+        'CallSession:notifyRecordOptions: cannot resume recording, ignoring request ');
+      return false;
+    }
 
-      switch (action) {
-        case 'startCallRecording':
-          return await this.startRecording();
-        case 'stopCallRecording':
-          return await this.stopRecording();
-        case 'pauseCallRecording':
-          return await this.pauseRecording();
-        case 'resumeCallRecording':
-          return await this.resumeRecording();
-        default:
-          throw new Error(`invalid record action ${action}`);
-      }
+    this.recordOptions = opts;
+
+    switch (action) {
+      case 'startCallRecording':
+        return await this.startRecording();
+      case 'stopCallRecording':
+        return await this.stopRecording();
+      case 'pauseCallRecording':
+        return await this.pauseRecording();
+      case 'resumeCallRecording':
+        return await this.resumeRecording();
+      default:
+        throw new Error(`invalid record action ${action}`);
     }
   }
 
@@ -2500,36 +2468,6 @@ Duration=${duration} `
       }
       else {
         this.logger.error(err, `Error attempting to allocate endpoint for for task ${task.name}`);
-        // Check for SipError type (e.g., 488 codec incompatibility)
-        const isSipError = err.name === 'SipError';
-        if (isSipError && err.status) {
-          // Extract Reason header from SIP response if available (e.g., Q.850;cause=88;text="INCOMPATIBLE_DESTINATION")
-          const sipReasonHeader = err.res?.msg?.headers?.reason;
-          this._endpointAllocationError = {
-            status: err.status,
-            reason: err.reason || 'Endpoint Allocation Failed',
-            sipReasonHeader
-          };
-          this.logger.info({endpointAllocationError: this._endpointAllocationError},
-            'Captured SipError for propagation to SBC');
-
-          // Send SIP error response immediately for inbound calls
-          if (this.res && !this.res.finalResponseSent) {
-            this.logger.info(`Sending ${err.status} response to SBC due to SipError`);
-            this.res.send(err.status, {
-              headers: {
-                'X-Reason': `endpoint allocation failure: ${err.reason || 'Endpoint Allocation Failed'}`,
-                ...(sipReasonHeader && {'Reason': sipReasonHeader})
-              }
-            });
-            this._notifyCallStatusChange({
-              callStatus: CallStatus.Failed,
-              sipStatus: err.status,
-              sipReason: err.reason || 'Endpoint Allocation Failed'
-            });
-            this._callReleased();
-          }
-        }
         throw new Error(`${BADPRECONDITIONS}: unable to allocate endpoint`);
       }
     }
@@ -3042,7 +2980,8 @@ Duration=${duration} `
 
     // manage record all call.
     if (callStatus === CallStatus.InProgress) {
-      if (this.accountInfo.account.record_all_calls || this.application.record_all_calls) {
+      if (this.accountInfo.account.record_all_calls ||
+        this.application.record_all_calls) {
         this.backgroundTaskManager.newTask('record');
       }
     } else if (callStatus == CallStatus.Completed) {

lib/session/inbound-call-session.js

@@ -60,19 +60,6 @@ class InboundCallSession extends CallSession {
           }
         });
       }
-      else if (this._endpointAllocationError) {
-        // Propagate SIP error from endpoint allocation failure back to the client
-        const {status, reason, sipReasonHeader} = this._endpointAllocationError;
-        this.rootSpan.setAttributes({'call.termination': `endpoint allocation SIP error ${status}`});
-        this.logger.info({endpointAllocationError: this._endpointAllocationError},
-          `InboundCallSession:_onTasksDone generating ${status} due to endpoint allocation failure`);
-        this.res.send(status, {
-          headers: {
-            'X-Reason': `endpoint allocation failure: ${reason}`,
-            ...(sipReasonHeader && {'Reason': sipReasonHeader})
-          }
-        });
-      }
       else {
         this.rootSpan.setAttributes({'call.termination': 'tasks completed without answering call'});
         this.logger.info('InboundCallSession:_onTasksDone auto-generating non-success response to invite');

lib/tasks/gather.js

@@ -500,10 +500,6 @@ class TaskGather extends SttTask {
         this.addCustomEventListener(ep, GladiaTranscriptionEvents.ConnectFailure,
           this._onVendorConnectFailure.bind(this, cs, ep));
         this.addCustomEventListener(ep, GladiaTranscriptionEvents.Error, this._onVendorError.bind(this, cs, ep));
-        // gladia require unique url for each session
-        const {host, path} = await this.createGladiaLiveSession();
-        opts.GLADIA_SPEECH_HOST = host;
-        opts.GLADIA_SPEECH_PATH = path;
         break;
 
       case 'soniox':

lib/tasks/redirect.js

@@ -1,6 +1,7 @@
 const Task = require('./task');
 const {TaskName} = require('../utils/constants');
 const WsRequestor = require('../utils/ws-requestor');
+const URL = require('url');
 const HttpRequestor = require('../utils/http-requestor');
 
 /**
@@ -9,7 +10,6 @@ const HttpRequestor = require('../utils/http-requestor');
 class TaskRedirect extends Task {
   constructor(logger, opts) {
     super(logger, opts);
-    this.statusHook = opts.statusHook || false;
   }
 
   get name() { return TaskName.Redirect; }
@@ -33,7 +33,7 @@ class TaskRedirect extends Task {
       }
       else {
         const baseUrl =  this.cs.application.requestor.baseUrl;
-        const newUrl = new URL(this.actionHook);
+        const newUrl = URL.parse(this.actionHook);
         const newBaseUrl = newUrl.protocol + '//' + newUrl.host;
         if (baseUrl != newBaseUrl) {
           try {
@@ -47,30 +47,6 @@ class TaskRedirect extends Task {
         }
       }
     }
-
-    /* update the notifier if a new statusHook was provided */
-    if (this.statusHook) {
-      this.logger.info(`TaskRedirect updating statusHook to ${this.statusHook}`);
-      try {
-        const oldNotifier = cs.application.notifier;
-        const isStatusHookAbsolute = cs.notifier?._isAbsoluteUrl(this.statusHook);
-        if (isStatusHookAbsolute) {
-          if (cs.notifier instanceof WsRequestor) {
-            cs.application.notifier = new WsRequestor(this.logger, cs.accountSid, {url: this.statusHook},
-              cs.accountInfo.account.webhook_secret);
-          } else {
-            cs.application.notifier = new HttpRequestor(this.logger, cs.accountSid, {url: this.statusHook},
-              cs.accountInfo.account.webhook_secret);
-          }
-          if (oldNotifier?.close) oldNotifier.close();
-        }
-        /* update the call_status_hook URL that gets passed to the notifier */
-        cs.application.call_status_hook = this.statusHook;
-      } catch (err) {
-        this.logger.info(err, `TaskRedirect error updating statusHook to ${this.statusHook}`);
-      }
-    }
-
     await this.performAction();
   }
 }

lib/tasks/stt-task.js

@@ -203,14 +203,26 @@ class SttTask extends Task {
     if (cs.hasGlobalSttPunctuation && !this.data.recognizer.punctuation) {
       this.data.recognizer.punctuation = cs.globalSttPunctuation;
     }
+    if (this.vendor === 'gladia') {
+      const { api_key, region } = this.sttCredentials;
+      const {url} = await this.createGladiaLiveSession({
+        api_key, region,
+        model: this.data.recognizer.model || 'solaria-1',
+        options: this.data.recognizer.gladiaOptions || {}
+      });
+      const {host, pathname, search} = new URL(url);
+      this.sttCredentials.host = host;
+      this.sttCredentials.path = `${pathname}${search}`;
+    }
   }
 
 
-  async createGladiaLiveSession() {
-    const { api_key, region = 'us-west' } = this.sttCredentials;
-    const model = this.data.recognizer.model || 'solaria-1';
-    const options = this.data.recognizer.gladiaOptions || {};
-
+  async createGladiaLiveSession({
+    api_key,
+    region = 'us-west',
+    model = 'solaria-1',
+    options = {},
+  }) {
     const url = `https://api.gladia.io/v2/live?region=${region}`;
     const response = await fetch(url, {
       method: 'POST',
@@ -240,9 +252,7 @@ class SttTask extends Task {
 
     const data = await response.json();
     this.logger.debug({url: data.url}, 'Gladia Call registered');
-
-    const {host, pathname, search} = new URL(data.url);
-    return {host, path: `${pathname}${search}`};
+    return data;
   }
 
   addCustomEventListener(ep, event, handler) {

lib/tasks/transcribe.js

@@ -459,14 +459,6 @@ class TaskTranscribe extends SttTask {
       else if (this.data.recognizer?.hints?.length > 0) {
         prompt = this.data.recognizer?.hints.join(', ');
       }
-    } else if (this.vendor === 'gladia') {
-      // gladia require unique url for each session
-      const {host, path} = await this.createGladiaLiveSession();
-      await ep.set({
-        GLADIA_SPEECH_HOST: host,
-        GLADIA_SPEECH_PATH: path,
-      })
-        .catch((err) => this.logger.info(err, 'Error setting channel variables'));
     }
 
     await ep.startTranscription({

lib/utils/action-hook-delay.js

@@ -118,13 +118,6 @@ class ActionHookDelayProcessor extends Emitter {
     this.logger.debug('ActionHookDelayProcessor#_onNoResponseTimer');
     this._noResponseTimer = null;
 
-    /* check if endpoint is still available (call may have ended) */
-    if (!this.ep) {
-      this.logger.debug('ActionHookDelayProcessor#_onNoResponseTimer: endpoint is null, call may have ended');
-      this._active = false;
-      return;
-    }
-
     /* get the next play or say action */
     const verb = this.actions[this._retryCount % this.actions.length];
 
@@ -136,8 +129,8 @@ class ActionHookDelayProcessor extends Emitter {
       this._taskInProgress.exec(this.cs, {ep: this.ep}).catch((err) => {
         this.logger.info(`ActionHookDelayProcessor#_onNoResponseTimer: error playing file: ${err.message}`);
         this._taskInProgress = null;
-        this.ep?.removeAllListeners('playback-start');
-        this.ep?.removeAllListeners('playback-stop');
+        this.ep.removeAllListeners('playback-start');
+        this.ep.removeAllListeners('playback-stop');
       });
     } catch (err) {
       this.logger.info(err, 'ActionHookDelayProcessor#_onNoResponseTimer: error starting action');

lib/utils/background-task-manager.js

@@ -135,24 +135,26 @@ class BackgroundTaskManager extends Emitter {
 
   // Initiate Record
   async _initRecord() {
-    if (!JAMBONZ_RECORD_WS_BASE_URL || !this.cs.accountInfo.account.bucket_credential) {
-      this.logger.error('_initRecord: invalid cfg - missing JAMBONZ_RECORD_WS_BASE_URL or bucket config');
-      return undefined;
-    }
-    const listenOpts = {
-      url: `${JAMBONZ_RECORD_WS_BASE_URL}/record/${this.cs.accountInfo.account.bucket_credential.vendor}`,
-      disableBidirectionalAudio: true,
-      mixType : 'stereo',
-      passDtmf: true
-    };
-    if (JAMBONZ_RECORD_WS_USERNAME && JAMBONZ_RECORD_WS_PASSWORD) {
-      listenOpts.wsAuth = {
-        username: JAMBONZ_RECORD_WS_USERNAME,
-        password: JAMBONZ_RECORD_WS_PASSWORD
+    if (this.cs.accountInfo.account.record_all_calls || this.cs.application.record_all_calls) {
+      if (!JAMBONZ_RECORD_WS_BASE_URL || !this.cs.accountInfo.account.bucket_credential) {
+        this.logger.error('_initRecord: invalid cfg - missing JAMBONZ_RECORD_WS_BASE_URL or bucket config');
+        return undefined;
+      }
+      const listenOpts = {
+        url: `${JAMBONZ_RECORD_WS_BASE_URL}/record/${this.cs.accountInfo.account.bucket_credential.vendor}`,
+        disableBidirectionalAudio: true,
+        mixType : 'stereo',
+        passDtmf: true
       };
+      if (JAMBONZ_RECORD_WS_USERNAME && JAMBONZ_RECORD_WS_PASSWORD) {
+        listenOpts.wsAuth = {
+          username: JAMBONZ_RECORD_WS_USERNAME,
+          password: JAMBONZ_RECORD_WS_PASSWORD
+        };
+      }
+      this.logger.debug({listenOpts}, '_initRecord: enabling listen');
+      return await this._initListen({verb: 'listen', ...listenOpts}, 'jambonz-session-record', true, 'record');
     }
-    this.logger.debug({listenOpts}, '_initRecord: enabling listen');
-    return await this._initListen({verb: 'listen', ...listenOpts}, 'jambonz-session-record', true, 'record');
   }
 
   // Initiate Transcribe

lib/utils/sbc-pinger.js

@@ -120,8 +120,17 @@ module.exports = (logger) => {
       }
       pingProxies(srf);
 
-      // Note: in response to SIGUSR1 we start drying up but do not exit when calls reach zero.
-      // This is to allow external scripts that sent the signal to manage the lifecycle.
+      // if we have zero calls, we can complete the scale-in right
+      setTimeout(() => {
+        const calls = srf.locals.sessionTracker.count;
+        if (calls === 0) {
+          logger.info('scale-in can complete immediately as we have no calls in progress');
+          process.exit(0);
+        }
+        else {
+          logger.info(`${calls} calls in progress; scale-in will complete when they are done`);
+        }
+      }, 5000);
     });
   }
 

lib/utils/transcription-utils.js

@@ -1085,6 +1085,13 @@ module.exports = (logger) => {
         ...(keyterms && keyterms.length > 0 && {DEEPGRAMFLUX_SPEECH_KEYTERMS: keyterms.join(',')}),
       };
     }
+    else if ('gladia' === vendor) {
+      const {host, path} = sttCredentials;
+      opts = {
+        GLADIA_SPEECH_HOST: host,
+        GLADIA_SPEECH_PATH: path,
+      };
+    }
     else if ('soniox' === vendor) {
       const {sonioxOptions = {}} = rOpts;
       const {storage = {}} = sonioxOptions;
@@ -1310,9 +1317,6 @@ module.exports = (logger) => {
           ...(openaiOptions.turn_detection.silence_duration_ms && {
             OPENAI_TURN_DETECTION_SILENCE_DURATION_MS: openaiOptions.turn_detection.silence_duration_ms
           }),
-          ...(openaiOptions.turn_detection.eagerness && {
-            OPENAI_TURN_DETECTION_EAGERNESS: openaiOptions.turn_detection.eagerness
-          })
         };
       }
     }

lib/utils/tts-streaming-buffer.js

@@ -220,7 +220,8 @@ class TtsStreamingBuffer extends Emitter {
           this.queue.shift();
         }
         // Immediately send all accumulated text (ignoring sentence boundaries).
-        if (flushText.length > 0) {
+        // Skip sending if flushText is only whitespace.
+        if (flushText.length > 0 && !isWhitespace(flushText)) {
           const modifiedFlushText = flushText.replace(/\n\n/g, '\n \n');
           try {
             await this._api(this.ep, [this.ep.uuid, 'send', modifiedFlushText]);

package-lock.json

@@ -18,7 +18,7 @@
         "@jambonz/speech-utils": "^0.2.26",
         "@jambonz/stats-collector": "^0.1.10",
         "@jambonz/time-series": "^0.2.15",
-        "@jambonz/verb-specifications": "^0.0.125",
+        "@jambonz/verb-specifications": "^0.0.122",
         "@modelcontextprotocol/sdk": "^1.9.0",
         "@opentelemetry/api": "^1.8.0",
         "@opentelemetry/exporter-jaeger": "^1.23.0",
@@ -1529,9 +1529,9 @@
       }
     },
     "node_modules/@jambonz/verb-specifications": {
-      "version": "0.0.125",
-      "resolved": "https://registry.npmjs.org/@jambonz/verb-specifications/-/verb-specifications-0.0.125.tgz",
-      "integrity": "sha512-lU1fyyYyjXOdIfQ2gmOFmssZASYNu6LD066iXjqFrBJpiI7shkprcZ1qeWGibuEk9nR2k+em3/YL31Wc8L4wvA==",
+      "version": "0.0.122",
+      "resolved": "https://registry.npmjs.org/@jambonz/verb-specifications/-/verb-specifications-0.0.122.tgz",
+      "integrity": "sha512-7xqaULhKFywJ2ZuyiYt77iiJwJ+8b98Zt1X4+OqZ7Cdjhfo7S6KnR66XRVJHnekXbmfVv58kB0KWUux5TG//Sw==",
       "license": "MIT",
       "dependencies": {
         "debug": "^4.3.4",

package.json

@@ -34,7 +34,7 @@
     "@jambonz/speech-utils": "^0.2.26",
     "@jambonz/stats-collector": "^0.1.10",
     "@jambonz/time-series": "^0.2.15",
-    "@jambonz/verb-specifications": "^0.0.125",
+    "@jambonz/verb-specifications": "^0.0.122",
     "@modelcontextprotocol/sdk": "^1.9.0",
     "@opentelemetry/api": "^1.8.0",
     "@opentelemetry/exporter-jaeger": "^1.23.0",

test/index.js

@@ -4,6 +4,7 @@ require('./ws-requestor-unit-test');
 require('./http-requestor-retry-test');
 require('./http-requestor-unit-test');
 require('./unit-tests');
+require('./tts-streaming-buffer-test');
 require('./docker_start');
 require('./create-test-db');
 require('./account-validation-tests');

test/tts-streaming-buffer-test.js

@@ -0,0 +1,177 @@
+const test = require('tape');
+const sinon = require('sinon');
+
+const noop = () => {};
+const logger = {
+  error: noop,
+  info: noop,
+  debug: noop
+};
+
+const {
+  TtsStreamingConnectionStatus
+} = require('../lib/utils/constants.json');
+
+const TtsStreamingBuffer = require('../lib/utils/tts-streaming-buffer');
+
+// Helper to create a mock CallSession
+function createMockCs(options = {}) {
+  const mockEp = {
+    uuid: 'test-uuid-1234',
+    api: sinon.stub().resolves({ body: '+OK' }),
+    addCustomEventListener: sinon.stub(),
+    removeCustomEventListener: sinon.stub()
+  };
+
+  return {
+    logger,
+    ep: mockEp,
+    isTtsStreamOpen: options.isTtsStreamOpen !== undefined ? options.isTtsStreamOpen : true,
+    getTsStreamingVendor: () => options.vendor || 'deepgram'
+  };
+}
+
+/**
+ * BUG REPRODUCTION TEST
+ *
+ * This test reproduces the exact issue from production logs:
+ * {
+ *   "args": ["uuid", "send", " "],
+ *   "msg": "Error calling uuid_deepgram_tts_streaming: -USAGE: <uuid> connect|send|clear|close [tokens]"
+ * }
+ *
+ * Root cause: When multiple flushes are queued while connecting, and a space token
+ * gets buffered between flushes, Phase 1 of _feedQueue sends that space to the TTS vendor.
+ *
+ * Sequence:
+ * 1. bufferTokens('Hello.') while connecting
+ * 2. flush() while connecting
+ * 3. bufferTokens(' ') while connecting (passes because bufferedLength > 0)
+ * 4. flush() while connecting
+ * 5. Connection completes, _feedQueue processes: [text:Hello., flush, text:" ", flush]
+ * 6. First flush sends "Hello." - OK
+ * 7. Second flush sends " " - BUG!
+ */
+test('TtsStreamingBuffer: multiple flushes while connecting - space token sent to TTS vendor', async(t) => {
+  const cs = createMockCs();
+  const buffer = new TtsStreamingBuffer(cs);
+
+  buffer._connectionStatus = TtsStreamingConnectionStatus.Connecting;
+  buffer.vendor = 'deepgram';
+
+  const apiCalls = [];
+  const originalApi = buffer._api.bind(buffer);
+  buffer._api = async function(ep, args) {
+    apiCalls.push({ args: [...args] });
+    return originalApi(ep, args);
+  };
+
+  // First batch while connecting
+  await buffer.bufferTokens('Hello.');
+  buffer.flush();
+
+  // Second batch - just a space (passes because bufferedLength > 0)
+  await buffer.bufferTokens(' ');
+  buffer.flush();
+
+  // Verify queue state before connect
+  t.equal(buffer.queue.length, 4, 'queue should have 4 items: [text, flush, text, flush]');
+  t.equal(buffer.queue[0].type, 'text', 'first item should be text');
+  t.equal(buffer.queue[0].value, 'Hello.', 'first text should be "Hello."');
+  t.equal(buffer.queue[1].type, 'flush', 'second item should be flush');
+  t.equal(buffer.queue[2].type, 'text', 'third item should be text');
+  t.equal(buffer.queue[2].value, ' ', 'third item should be space');
+  t.equal(buffer.queue[3].type, 'flush', 'fourth item should be flush');
+
+  // Connect - triggers _feedQueue
+  buffer._connectionStatus = TtsStreamingConnectionStatus.Connected;
+  await buffer._feedQueue();
+
+  // Check API calls
+  const sendCalls = apiCalls.filter(call => call.args[1] === 'send');
+
+  // This assertion will FAIL until the bug is fixed
+  const whitespaceOnlySends = sendCalls.filter(call => /^\s*$/.test(call.args[2]));
+
+  t.equal(whitespaceOnlySends.length, 0,
+    `should not send whitespace-only tokens, but sent: ${whitespaceOnlySends.map(c => JSON.stringify(c.args[2])).join(', ')}`);
+
+  t.end();
+});
+
+/**
+ * Additional test: Verify text with trailing space in same flush is OK
+ */
+test('TtsStreamingBuffer: text with trailing space in same flush should work', async(t) => {
+  const cs = createMockCs();
+  const buffer = new TtsStreamingBuffer(cs);
+
+  buffer._connectionStatus = TtsStreamingConnectionStatus.Connecting;
+  buffer.vendor = 'deepgram';
+
+  const apiCalls = [];
+  const originalApi = buffer._api.bind(buffer);
+  buffer._api = async function(ep, args) {
+    apiCalls.push({ args: [...args] });
+    return originalApi(ep, args);
+  };
+
+  // Buffer text with trailing space, then flush
+  await buffer.bufferTokens('Hello.');
+  await buffer.bufferTokens(' ');
+  buffer.flush();
+
+  // Connect
+  buffer._connectionStatus = TtsStreamingConnectionStatus.Connected;
+  await buffer._feedQueue();
+
+  const sendCalls = apiCalls.filter(call => call.args[1] === 'send');
+
+  t.equal(sendCalls.length, 1, 'should have one send call');
+  t.equal(sendCalls[0].args[2], 'Hello. ', 'should send "Hello. " (text with trailing space)');
+
+  t.end();
+});
+
+/**
+ * Test: Leading whitespace should be discarded when buffer is empty
+ */
+test('TtsStreamingBuffer: leading whitespace discarded when buffer empty', async(t) => {
+  const cs = createMockCs();
+  const buffer = new TtsStreamingBuffer(cs);
+
+  buffer._connectionStatus = TtsStreamingConnectionStatus.Connected;
+  buffer.vendor = 'deepgram';
+
+  // Try to buffer whitespace when buffer is empty
+  const result = await buffer.bufferTokens('   ');
+
+  t.equal(result.status, 'ok', 'should return ok status');
+  t.equal(buffer.bufferedLength, 0, 'buffer should remain empty');
+  t.equal(buffer.queue.length, 0, 'queue should remain empty');
+
+  t.end();
+});
+
+/**
+ * Test: Whitespace can be buffered when buffer has content
+ */
+test('TtsStreamingBuffer: whitespace accepted when buffer has content', async(t) => {
+  const cs = createMockCs();
+  const buffer = new TtsStreamingBuffer(cs);
+
+  buffer._connectionStatus = TtsStreamingConnectionStatus.Connecting;
+  buffer.vendor = 'deepgram';
+
+  // Buffer real text first
+  await buffer.bufferTokens('Hello');
+
+  // Now buffer whitespace (should pass because bufferedLength > 0)
+  const result = await buffer.bufferTokens(' ');
+
+  t.equal(result.status, 'ok', 'should return ok status');
+  t.equal(buffer.bufferedLength, 6, 'buffer should have 6 chars');
+  t.equal(buffer.queue.length, 2, 'queue should have 2 items');
+
+  t.end();
+});