feat: voice and language support in cal.ai (calcom#23865)

* feat: lang support

* fix: type errors

* feat: select voice agent

* refactor: address feedback

* refactor: address feedback

* refactor: missing import

* fix: types

Author: Udit-takkar

apps/web/public/icons/sprite.svg

@@ -3704,5 +3704,13 @@
   "start_from_scratch_description": "Create your own workflow from scratch.",
   "cal_ai_template_title": "Cal.ai template",
   "cal_ai_template_description": "AI agents that book meetings, send reminders, and follow up!",
+  "voice": "Voice",
+  "select_voice": "Select Voice",
+  "select_voice_for_agent": "Select a voice for your agent",
+  "choose_a_voice_for_your_agent": "Choose a voice for your agent",
+  "trait": "Trait",
+  "voice_id": "Voice ID",
+  "use_voice": "Use Voice",
+  "current_voice": "Current Voice",
   "ADD_NEW_STRINGS_ABOVE_THIS_LINE_TO_PREVENT_MERGE_CONFLICTS": "↑↑↑↑↑↑↑↑↑↑↑↑↑ Add your new strings above here ↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑↑"
 }

apps/web/public/static/locales/en/common.json

@@ -96,6 +96,9 @@ export type AIPhoneServiceListCallsResponse<
   T extends AIPhoneServiceProviderType = AIPhoneServiceProviderType
 > = AIPhoneServiceProviderTypeMap[T]["ListCallsResponse"];
 
+export type AIPhoneServiceVoice<T extends AIPhoneServiceProviderType = AIPhoneServiceProviderType> =
+  AIPhoneServiceProviderTypeMap[T]["Voice"];
+
 export interface AIPhoneServiceDeletion {
   modelId?: string;
   agentId?: string;
@@ -311,6 +314,7 @@ export interface AIPhoneServiceProvider<T extends AIPhoneServiceProviderType = A
     beginMessage?: string | null;
     generalTools?: AIPhoneServiceTools<T>;
     voiceId?: string;
+    language?: string;
   }): Promise<{ message: string }>;
 
   /**
@@ -374,6 +378,11 @@ export interface AIPhoneServiceProvider<T extends AIPhoneServiceProviderType = A
       startTimestamp?: { lower_threshold?: number; upper_threshold?: number };
     };
   }): Promise<AIPhoneServiceListCallsResponse<T>>;
+
+  /**
+   * List available voices
+   */
+  listVoices(): Promise<AIPhoneServiceVoice<T>[]>;
 }
 
 /**

packages/features/calAIPhone/interfaces/AIPhoneService.interface.ts

@@ -22,7 +22,7 @@ import type { AgentRepositoryInterface } from "../interfaces/AgentRepositoryInte
 import type { PhoneNumberRepositoryInterface } from "../interfaces/PhoneNumberRepositoryInterface";
 import type { TransactionInterface } from "../interfaces/TransactionInterface";
 import { RetellAIService } from "./RetellAIService";
-import type { RetellAIRepository } from "./types";
+import type { RetellAIRepository, Language } from "./types";
 
 export class RetellAIPhoneServiceProvider
   implements AIPhoneServiceProvider<AIPhoneServiceProviderType.RETELL_AI>
@@ -243,6 +243,7 @@ export class RetellAIPhoneServiceProvider
     beginMessage?: string | null;
     generalTools?: AIPhoneServiceTools<AIPhoneServiceProviderType.RETELL_AI>;
     voiceId?: string;
+    language?: Language;
   }): Promise<{ message: string }> {
     return await this.service.updateAgentConfiguration(params);
   }
@@ -302,4 +303,8 @@ export class RetellAIPhoneServiceProvider
   }) {
     return await this.service.listCalls(params);
   }
+
+  async listVoices() {
+    return await this.service.listVoices();
+  }
 }

packages/features/calAIPhone/providers/retellAI/RetellAIPhoneServiceProvider.ts

@@ -12,6 +12,7 @@ import { AgentService } from "./services/AgentService";
 import { BillingService } from "./services/BillingService";
 import { CallService } from "./services/CallService";
 import { PhoneNumberService } from "./services/PhoneNumberService";
+import { VoiceService } from "./services/VoiceService";
 import type {
   RetellLLM,
   RetellCall,
@@ -32,6 +33,7 @@ export class RetellAIService {
   private billingService: BillingService;
   private callService: CallService;
   private phoneNumberService: PhoneNumberService;
+  private voiceService: VoiceService;
 
   constructor(
     private repository: RetellAIRepository,
@@ -49,6 +51,7 @@ export class RetellAIService {
       phoneNumberRepository,
       transactionManager
     );
+    this.voiceService = new VoiceService(repository);
 
     // Inject RetellAIService reference into CallService
     this.callService.setRetellAIService(this);
@@ -171,6 +174,7 @@ export class RetellAIService {
     beginMessage?: string | null;
     generalTools?: RetellLLMGeneralTools;
     voiceId?: string;
+    language?: Language;
   }) {
     return this.agentService.updateAgentConfiguration({
       ...params,
@@ -254,4 +258,8 @@ export class RetellAIService {
   }) {
     return this.callService.listCalls(params);
   }
+
+  async listVoices() {
+    return this.voiceService.listVoices();
+  }
 }

packages/features/calAIPhone/providers/retellAI/RetellAIService.ts

@@ -16,6 +16,7 @@ import type {
   ImportPhoneNumberParams,
   RetellCallListParams,
   RetellCallListResponse,
+  RetellVoice,
 } from "./types";
 
 const RETELL_API_KEY = process.env.RETELL_AI_KEY;
@@ -270,4 +271,16 @@ export class RetellSDKClient implements RetellAIRepository {
       throw error;
     }
   }
+
+  async listVoices(): Promise<RetellVoice[]> {
+
+    try {
+      const response = await this.client.voice.list();
+
+      return response;
+    } catch (error) {
+      this.logger.error("Failed to list voices", { error });
+      throw error;
+    }
+  }
 }

packages/features/calAIPhone/providers/retellAI/RetellSDKClient.ts

@@ -21,6 +21,7 @@ import type {
   RetellDynamicVariables,
   RetellCallListParams,
   RetellCallListResponse,
+  RetellVoice,
 } from "./types";
 
 export { RetellAIService } from "./RetellAIService";
@@ -30,6 +31,7 @@ export { AgentService } from "./services/AgentService";
 export { BillingService } from "./services/BillingService";
 export { CallService } from "./services/CallService";
 export { PhoneNumberService } from "./services/PhoneNumberService";
+export { VoiceService } from "./services/VoiceService";
 
 export { RetellAIPhoneServiceProvider } from "./RetellAIPhoneServiceProvider";
 export { RetellAIPhoneServiceProviderFactory } from "./RetellAIPhoneServiceProviderFactory";
@@ -65,6 +67,7 @@ export type {
   RetellDynamicVariables,
   RetellCallListParams,
   RetellCallListResponse,
+  RetellVoice,
 };
 
 export interface RetellAIPhoneServiceProviderTypeMap {
@@ -83,6 +86,7 @@ export interface RetellAIPhoneServiceProviderTypeMap {
   AgentWithDetails: RetellAgentWithDetails;
   ListCallsParams: RetellCallListParams;
   ListCallsResponse: RetellCallListResponse;
+  Voice: RetellVoice;
 }
 
 // ===== USAGE EXAMPLES =====

packages/features/calAIPhone/providers/retellAI/index.ts

@@ -507,6 +507,7 @@ export class AgentService {
     beginMessage,
     generalTools,
     voiceId,
+    language,
     updateLLMConfiguration,
   }: {
     id: string;
@@ -517,6 +518,7 @@ export class AgentService {
     beginMessage?: string | null;
     generalTools?: AIPhoneServiceTools<AIPhoneServiceProviderType.RETELL_AI>;
     voiceId?: string;
+    language?: Language;
     updateLLMConfiguration: (
       llmId: string,
       data: AIPhoneServiceUpdateModelParams<AIPhoneServiceProviderType.RETELL_AI>
@@ -539,7 +541,8 @@ export class AgentService {
       generalPrompt !== undefined ||
       beginMessage !== undefined ||
       generalTools !== undefined ||
-      voiceId !== undefined;
+      voiceId !== undefined ||
+      language !== undefined;
 
     if (hasRetellUpdates) {
       try {
@@ -558,10 +561,11 @@ export class AgentService {
           await updateLLMConfiguration(llmId, llmUpdateData);
         }
 
-        if (voiceId) {
-          await this.updateAgent(agent.providerAgentId, {
-            voice_id: voiceId,
-          });
+        if (voiceId || language) {
+          const agentUpdateData: Parameters<typeof this.updateAgent>[1] = {};
+          if (voiceId) agentUpdateData.voice_id = voiceId;
+          if (language) agentUpdateData.language = language;
+          await this.updateAgent(agent.providerAgentId, agentUpdateData);
         }
       } catch (error) {
         this.logger.error("Failed to update agent configuration in external AI service", {

packages/features/calAIPhone/providers/retellAI/services/AgentService.ts

@@ -0,0 +1,30 @@
+import { HttpError } from "@calcom/lib/http-error";
+import logger from "@calcom/lib/logger";
+
+import type { RetellAIRepository, RetellVoice } from "../types";
+
+export class VoiceService {
+  private logger = logger.getSubLogger({ prefix: ["VoiceService"] });
+
+  constructor(private retellRepository: RetellAIRepository) {}
+
+  async listVoices(): Promise<RetellVoice[]> {
+    try {
+      const voices = await this.retellRepository.listVoices();
+      
+      this.logger.info("Retrieved voices successfully", {
+        count: voices.length,
+      });
+      
+      return voices;
+    } catch (error) {
+      this.logger.error("Failed to list voices from external AI service", {
+        error,
+      });
+      throw new HttpError({
+        statusCode: 500,
+        message: "Failed to retrieve available voices. Please try again.",
+      });
+    }
+  }
+}

packages/features/calAIPhone/providers/retellAI/services/VoiceService.ts

@@ -6,6 +6,7 @@ export type RetellLLM = Retell.LlmResponse;
 export type RetellPhoneNumber = Retell.PhoneNumberResponse;
 export type RetellCall = Retell.PhoneCallResponse;
 export type RetellDynamicVariables = { [key: string]: unknown };
+export type RetellVoice = Retell.VoiceResponse;
 
 export type RetellAgent = Retell.AgentResponse;
 
@@ -186,4 +187,7 @@ export interface RetellAIRepository {
   createWebCall(
     data: CreateWebCallParams
   ): Promise<{ call_id: string; access_token: string; agent_id: string }>;
+
+  // Voice operations
+  listVoices(): Promise<RetellVoice[]>;
 }