feat(google-cloud): add Google Cloud Text-to-Speech plugin

.changeset/google-cloud-tts-plugin.md

@@ -0,0 +1,11 @@
+---
+"@livekit/agents-plugin-google-cloud": patch
+"@livekit/agents": patch
+---
+
+feat: add Google Cloud Text-to-Speech plugin
+
+Ports the Google Cloud TTS integration from the Python SDK, supporting both
+streaming (via gRPC bidirectional streaming) and non-streaming synthesis.
+Uses @google-cloud/text-to-speech client with standard Google Cloud auth
+(credentials object, keyFilename, GOOGLE_APPLICATION_CREDENTIALS, or ADC).

agents/src/utils.ts

@@ -334,11 +334,11 @@ export class AsyncIterableQueue<T> implements AsyncIterableIterator<T> {
     this.#queue.put(AsyncIterableQueue.CLOSE_SENTINEL);
   }
 
-  async next(): Promise<IteratorResult<T>> {
+  async next(options: { signal?: AbortSignal } = {}): Promise<IteratorResult<T>> {
     if (this.#closed && this.#queue.items.length === 0) {
       return { value: undefined, done: true };
     }
-    const item = await this.#queue.get();
+    const item = await this.#queue.get(options);
     if (item === AsyncIterableQueue.CLOSE_SENTINEL && this.#closed) {
       return { value: undefined, done: true };
     }

plugins/google-cloud/README.md

@@ -0,0 +1,60 @@
+<!--
+SPDX-FileCopyrightText: 2026 LiveKit, Inc.
+
+SPDX-License-Identifier: Apache-2.0
+-->
+
+# Google Cloud plugin for LiveKit Agents
+
+The Agents Framework is designed for building realtime, programmable
+participants that run on servers. Use it to create conversational, multi-modal
+voice agents that can see, hear, and understand.
+
+This package contains the Google Cloud plugin, which provides text-to-speech
+via the [Google Cloud Text-to-Speech API](https://cloud.google.com/text-to-speech).
+
+## Installation
+
+```bash
+pnpm add @livekit/agents-plugin-google-cloud
+```
+
+## Authentication
+
+Credentials are resolved by the underlying `@google-cloud/text-to-speech` client in order:
+
+1. `credentials` object passed directly (`{ client_email, private_key }`)
+2. `keyFilename` path to a service account JSON key file
+3. `GOOGLE_APPLICATION_CREDENTIALS` environment variable
+4. Application Default Credentials (auto-detected by `gcloud auth`)
+
+## Usage
+
+```typescript
+import { TTS } from '@livekit/agents-plugin-google-cloud';
+
+// Streaming synthesis (gRPC, default)
+const tts = new TTS({
+  language: 'en-US',
+  voiceName: 'en-US-Standard-H',
+});
+
+// Non-streaming synthesis (REST)
+const tts = new TTS({
+  language: 'en-IN',
+  voiceName: 'en-IN-Standard-C',
+  streaming: false,
+});
+
+// Streaming synthesis
+const stream = tts.stream();
+stream.pushText('Hello, world!');
+stream.flush();
+for await (const event of stream) {
+  // event.frame contains AudioFrame data
+}
+```
+
+## License
+
+Apache 2.0

plugins/google-cloud/api-extractor.json

@@ -0,0 +1,8 @@
+/**
+ * Config file for API Extractor.  For more info, please visit: https://api-extractor.com
+ */
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/api-extractor/v7/api-extractor.schema.json",
+  "extends": "../../api-extractor-shared.json",
+  "mainEntryPointFilePath": "./dist/index.d.ts"
+}

plugins/google-cloud/package.json

@@ -0,0 +1,51 @@
+{
+  "name": "@livekit/agents-plugin-google-cloud",
+  "version": "1.4.4",
+  "description": "Google Cloud TTS plugin for LiveKit Node Agents",
+  "main": "dist/index.js",
+  "require": "dist/index.cjs",
+  "types": "dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    },
+    "require": {
+      "types": "./dist/index.d.cts",
+      "default": "./dist/index.cjs"
+    }
+  },
+  "author": "LiveKit",
+  "type": "module",
+  "repository": "git@github.com:livekit/agents-js.git",
+  "license": "Apache-2.0",
+  "files": [
+    "dist",
+    "src",
+    "README.md"
+  ],
+  "scripts": {
+    "build": "tsup --onSuccess \"pnpm build:types\"",
+    "build:types": "tsc --declaration --emitDeclarationOnly && node ../../scripts/copyDeclarationOutput.js",
+    "clean": "rm -rf dist",
+    "clean:build": "pnpm clean && pnpm build",
+    "lint": "eslint -f unix \"src/**/*.{ts,js}\"",
+    "api:check": "api-extractor run --typescript-compiler-folder ../../node_modules/typescript",
+    "api:update": "api-extractor run --local --typescript-compiler-folder ../../node_modules/typescript --verbose"
+  },
+  "devDependencies": {
+    "@livekit/agents": "workspace:*",
+    "@livekit/agents-plugins-test": "workspace:*",
+    "@livekit/rtc-node": "catalog:",
+    "@microsoft/api-extractor": "^7.35.0",
+    "tsup": "^8.3.5",
+    "typescript": "^5.0.0"
+  },
+  "dependencies": {
+    "@google-cloud/text-to-speech": "^6.0.0"
+  },
+  "peerDependencies": {
+    "@livekit/agents": "workspace:*",
+    "@livekit/rtc-node": "catalog:"
+  }
+}

plugins/google-cloud/src/index.ts

@@ -0,0 +1,19 @@
+// SPDX-FileCopyrightText: 2026 LiveKit, Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+import { Plugin } from '@livekit/agents';
+
+export * from './models.js';
+export { ChunkedStream, SynthesizeStream, TTS, type TTSOptions } from './tts.js';
+
+class GoogleCloudPlugin extends Plugin {
+  constructor() {
+    super({
+      title: 'google-cloud',
+      version: __PACKAGE_VERSION__,
+      package: __PACKAGE_NAME__,
+    });
+  }
+}
+
+Plugin.registerPlugin(new GoogleCloudPlugin());

plugins/google-cloud/src/models.ts

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: 2026 LiveKit, Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+/** Google Cloud TTS models. */
+export type TTSModel =
+  | 'chirp-3'
+  | 'chirp-3-hd'
+  | 'journey'
+  | 'journey-2'
+  | 'chirp-2-hd'
+  | 'chirp-2-lq'
+  | string;
+
+/** Google Cloud TTS voice genders. */
+export type TTSGender = 'male' | 'female' | 'neutral';
+
+/** Speech language codes (BCP-47). */
+export type TTSLanguage =
+  | 'en-US'
+  | 'en-GB'
+  | 'en-AU'
+  | 'en-IN'
+  | 'hi-IN'
+  | 'bn-IN'
+  | 'ta-IN'
+  | 'te-IN'
+  | 'mr-IN'
+  | 'gu-IN'
+  | 'kn-IN'
+  | 'ml-IN'
+  | 'pa-IN'
+  | string;
+
+/** Audio encoding formats for non-streaming synthesis. */
+export type TTSAudioEncoding = 'LINEAR16' | 'MP3' | 'OGG_OPUS' | 'MULAW' | 'ALAW';
+
+/** Default voice name used when none is specified. */
+export const DEFAULT_VOICE_NAME = 'en-US-Standard-H';