Sync from internal repo (YYYY/MM/DD)

CLAUDE.md

@@ -17,7 +17,7 @@ const client = new AssemblyAI({
 
 const transcript = await client.transcripts.transcribe({
   audio: "https://example.com/audio.mp3",
-  speech_models: ["universal-3-pro", "universal-2"],
+  speech_models: ["universal-3-5-pro", "universal-2"],
   speaker_labels: true,
 });
 
@@ -59,7 +59,7 @@ const transcript = await client.transcripts.transcribe({
 ```typescript
 const transcript = await client.transcripts.transcribe({
   audio: audioUrl,
-  speech_models: ["universal-3-pro", "universal-2"],
+  speech_models: ["universal-3-5-pro", "universal-2"],
   speaker_labels: true,
   sentiment_analysis: true,
   entity_detection: true,
@@ -72,7 +72,7 @@ const transcript = await client.transcripts.transcribe({
 
 ```typescript
 const transcriber = client.streaming.transcriber({
-  speechModel: "u3-rt-pro",
+  speechModel: "universal-3-5-pro",
   sampleRate: 16_000,
 });
 
@@ -85,6 +85,88 @@ await transcriber.connect();
 await transcriber.close();
 ```
 
+For voice agents, `agentContext` (the agent's last reply, U3Pro only) is settable
+at connect time and updatable mid-stream after each agent turn:
+`transcriber.updateConfiguration({ agent_context: "..." })`.
+
+**Speaker revisions** (`speakerRevision` event, diarization-only — emitted only
+when `speakerLabels` is enabled). Sent once per offline-recluster resolve; each
+message batches every earlier Turn whose speaker label changed (unchanged turns
+are omitted). For each `revisions[i]`, match `turn_order` against the original
+Turn and replace its per-word `speaker` (and the turn-level `speaker_label`)
+with the revision's values — text and word timestamps are unchanged:
+
+```typescript
+transcriber.on("speakerRevision", (event) => {
+  for (const r of event.revisions) {
+    // r.turn_order, r.speaker_label, r.words[i].speaker
+  }
+});
+```
+
+**Dual-channel streaming (e.g. mic + system audio in a browser):**
+
+Dual-channel mode is configured on `StreamingTranscriber` itself by passing
+`channels`. All mixing, per-channel VAD, and per-word channel attribution
+happen inside the transcriber — runtime-agnostic, no browser required. Callers
+push tagged PCM via `sendAudio(pcm, { channel })`.
+
+For browsers, `DualChannelCapture` is a thin helper that pumps two
+`MediaStream`s into the transcriber:
+
+```typescript
+import { AssemblyAI, DualChannelCapture } from "assemblyai";
+
+const micStream = await navigator.mediaDevices.getUserMedia({
+  audio: { echoCancellation: true, noiseSuppression: true },
+});
+const systemStream = await navigator.mediaDevices.getDisplayMedia({
+  audio: true,
+});
+
+const transcriber = client.streaming.transcriber({
+  speechModel: "universal-3-5-pro",
+  sampleRate: 16_000,
+  speakerLabels: true,
+  channels: [{ name: "mic" }, { name: "system" }],
+});
+
+transcriber.on("turn", (turn) => {
+  // turn.words[i].channel: "mic" | "system" | "unknown"  (physical channel)
+  // turn.channel: duration-weighted rollup
+  // turn.speaker_label: AAI diarization, passed through unchanged
+});
+
+const capture = new DualChannelCapture({
+  micStream,
+  systemStream,
+  transcriber,
+});
+
+await transcriber.connect();
+await capture.start();
+```
+
+For non-browser runtimes (Node, telephony, file replay), bypass the helper and
+push tagged PCM directly:
+
+```typescript
+const transcriber = client.streaming.transcriber({
+  speechModel: "universal-3-5-pro",
+  sampleRate: 16_000,
+  channels: [{ name: "mic" }, { name: "system" }],
+});
+
+await transcriber.connect();
+transcriber.sendAudio(micPcm, { channel: "mic" });
+transcriber.sendAudio(systemPcm, { channel: "system" });
+```
+
+Channel attribution is additive — AAI's `speaker_label` / `words[i].speaker` are
+never overwritten. Echo cancellation must be set at `getUserMedia` time; the
+helper does not modify caller-provided MediaStream constraints. macOS needs a
+loopback driver (BlackHole, Loopback.app) for `getDisplayMedia` system audio.
+
 **Subtitles:**
 
 ```typescript
@@ -94,12 +176,12 @@ const vtt = await client.transcripts.subtitles(id, "vtt");
 
 ## Important gotchas
 
-- **`.transcribe()` polls until complete** — use `.submit()` for fire-and-forget
-- **`speech_models` takes an array** with fallback ordering: `["universal-3-pro", "universal-2"]`
-- **Streaming uses `u3-rt-pro`** as the speech model
+- **.transcribe() polls until complete** — use .submit() for fire-and-forget
+- **speech_models takes an array** with fallback ordering: ["universal-3-5-pro", "universal-2"]
+- **Streaming uses universal-3-5-pro** as the speech model
 - **Never expose API keys client-side** — use temporary auth tokens for browser streaming
 - **Node >= 18 required**
-- **Only runtime dependency**: `ws` (WebSocket library)
+- **Only runtime dependency**: ws (WebSocket library)
 - **Multi-runtime support**: Works in Node.js, Deno, Bun, Cloudflare Workers, and browsers
 
 ## Docs