feat(dictation): add rewrite_mode to DictationConfig

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## [4.41.6]
+
+- Add `rewrite_mode` to `DictationConfig` — the model tier that runs the dictation rewrite: `"fast"` (the server default) or `"smart"`, which follows detailed formatting instructions more reliably at higher latency. Unset, it is not sent. The `DictationRewriteMode` type is exported from the package root
+
 ## [4.41.5]
 
 - Add `speakerLabelsRevisionIntervalMs` streaming param (sent as `speaker_labels_revision_interval_ms`) — the cadence, in ms of audio time, at which the server emits mid-stream `speakerRevision` events when `speakerLabels` is enabled. Unset or `0` sends only the end-of-stream revision; non-zero values are clamped server-side to 120 000–300 000 ms. The first mid-stream revision needs ~120 s of streamed speech, and one is sent only when some earlier turn's label changed

CLAUDE.md

@@ -360,6 +360,7 @@ const result = await client.dictation.transcribeLive(mic, {
   stt_prompt: "A doctor dictating a patient visit note.", // max 6000 chars; describes the recording
   keyterms_prompt: ["AssemblyAI", "U3-Pro"], // whitespace stripped, empties dropped, max 100 terms, 8000 chars total
   llm_instruction: "Format this as a SOAP note.", // max 2048 chars; follow-up LLM pass over the transcript
+  rewrite_mode: "smart", // rewrite model tier: "fast" (server default) or "smart" (follows detailed instructions, slower)
 });
 ```
 
@@ -392,7 +393,7 @@ upload, the transcription and the LLM pass; the service caps audio at 120 s. `si
 
 **Exports** from the package root: `DictationTranscriber`, `DictationLiveSession`,
 `DictationError`, and the `DictationAudioInput`, `DictationConfig`, `DictationLiveOptions`,
-`DictationWord` and `DictationResponse` types.
+`DictationRewriteMode`, `DictationWord` and `DictationResponse` types.
 
 ## LLM Gateway
 

README.md

@@ -674,6 +674,17 @@ console.log(result.final_text); // llm_response when there is one, text otherwis
 When the LLM pass fails, `llm_response` is `null` and `llm_error` says why — the
 transcript itself still comes back.
 
+`rewrite_mode` picks the model tier that runs the rewrite. `"fast"` is the
+default; `"smart"` follows detailed formatting instructions more reliably, at
+higher latency:
+
+```typescript
+const result = await client.dictation.transcribeLive(micStream, {
+  llm_instruction: "Lowercase unless a name, no final punctuation.",
+  rewrite_mode: "smart",
+});
+```
+
 </details>
 
 <details>
@@ -687,6 +698,7 @@ const result = await client.dictation.transcribeLive(micStream, {
   stt_prompt: "A doctor dictating a patient visit note.", // max 6000 chars
   keyterms_prompt: ["AssemblyAI", "Universal-3"], // max 100 terms, 8000 chars total
   llm_instruction: "Format this as a SOAP note.", // max 2048 chars
+  rewrite_mode: "smart", // rewrite model tier: "fast" (default) or "smart"
 });
 ```
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "assemblyai",
-  "version": "4.41.5",
+  "version": "4.41.6",
   "description": "The AssemblyAI JavaScript SDK provides an easy-to-use interface for interacting with the AssemblyAI API, which supports async and real-time transcription.",
   "engines": {
     "node": ">=18"

src/services/dictation/service.ts

@@ -403,6 +403,8 @@ function buildConfigJson(config: DictationConfig): Record<string, unknown> {
   if (keytermsPrompt) json["keyterms_prompt"] = keytermsPrompt;
   if (config.llm_instruction !== undefined)
     json["llm_instruction"] = config.llm_instruction;
+  if (config.rewrite_mode !== undefined)
+    json["rewrite_mode"] = config.rewrite_mode;
 
   return json;
 }

src/types/dictation/index.ts

@@ -21,6 +21,13 @@ export type DictationAudioInput =
   | AsyncIterable<Uint8Array>
   | Iterable<Uint8Array>;
 
+/**
+ * The model tier that runs the transcript rewrite: `fast` (the server
+ * default) or `smart`, which follows detailed formatting instructions more
+ * reliably at higher latency.
+ */
+export type DictationRewriteMode = "fast" | "smart";
+
 /**
  * Options for a dictation request.
  *
@@ -75,6 +82,12 @@ export type DictationConfig = {
    * characters; longer instructions are rejected.
    */
   llm_instruction?: string;
+  /**
+   * The model tier that runs the rewrite: `"fast"` or `"smart"`. `"smart"`
+   * follows detailed formatting instructions more reliably at higher
+   * latency. Unset leaves the server default, `"fast"`.
+   */
+  rewrite_mode?: DictationRewriteMode;
 };
 
 /**

tests/unit/dictation.test.ts

@@ -433,6 +433,7 @@ describe("dictation config", () => {
       stt_prompt: "A doctor dictating a patient visit note.",
       keyterms_prompt: ["AssemblyAI", "U3-Pro"],
       llm_instruction: "Format this as a SOAP note.",
+      rewrite_mode: "smart",
     });
     expect(await configPart()).toEqual({
       sample_rate: 16000,
@@ -441,9 +442,18 @@ describe("dictation config", () => {
       stt_prompt: "A doctor dictating a patient visit note.",
       keyterms_prompt: ["AssemblyAI", "U3-Pro"],
       llm_instruction: "Format this as a SOAP note.",
+      rewrite_mode: "smart",
     });
   });
 
+  it("should leave rewrite_mode out when it is unset", async () => {
+    mockOk();
+    await assembly.dictation.transcribeLive(chunks(bytes("RIFF")), {
+      llm_instruction: "Clean this up.",
+    });
+    expect(await configPart()).toEqual({ llm_instruction: "Clean this up." });
+  });
+
   it("should never send keys the dictation API does not accept", async () => {
     mockOk();
     await assembly.dictation.transcribeLive(chunks(bytes("RIFF")), {