How to Build an AI Voice Call Agent with Python & VideoSDK

1python3 -m venv venv
2source venv/bin/activate  # On Windows: venv\Scripts\activate
3

1pip install videosdk-agents videosdk-plugins-silero videosdk-plugins-turn-detector videosdk-plugins-deepgram videosdk-plugins-openai videosdk-plugins-elevenlabs
2

1VIDEOSDK_API_KEY=your_videosdk_api_key
2DEEPGRAM_API_KEY=your_deepgram_api_key
3OPENAI_API_KEY=your_openai_api_key
4ELEVENLABS_API_KEY=your_elevenlabs_api_key
5

1import asyncio, os
2from videosdk.agents import Agent, AgentSession, CascadingPipeline, JobContext, RoomOptions, WorkerJob, ConversationFlow
3from videosdk.plugins.silero import SileroVAD
4from videosdk.plugins.turn_detector import TurnDetector, pre_download_model
5from videosdk.plugins.deepgram import DeepgramSTT
6from videosdk.plugins.openai import OpenAILLM
7from videosdk.plugins.elevenlabs import ElevenLabsTTS
8from typing import AsyncIterator
9
10# Pre-downloading the Turn Detector model
11pre_download_model()
12
13agent_instructions = "You are a professional and friendly AI Voice Call Assistant. Your primary role is to facilitate seamless, natural-sounding voice conversations with users over the phone. You can answer general questions, provide information, assist with scheduling, and guide users through automated processes. Always speak clearly, use polite language, and confirm understanding when necessary. You must never collect sensitive personal information (such as credit card numbers or social security numbers), and you cannot provide legal, medical, or financial advice. If a user requests such information or advice, politely inform them that you are unable to assist and recommend contacting a qualified professional. Always respect user privacy and comply with data protection guidelines. If you are unsure about a request, escalate or suggest speaking with a human representative."
14
15class MyVoiceAgent(Agent):
16    def __init__(self):
17        super().__init__(instructions=agent_instructions)
18    async def on_enter(self): await self.session.say("Hello! How can I help?")
19    async def on_exit(self): await self.session.say("Goodbye!")
20
21async def start_session(context: JobContext):
22    # Create agent and conversation flow
23    agent = MyVoiceAgent()
24    conversation_flow = ConversationFlow(agent)
25
26    # Create pipeline
27    pipeline = CascadingPipeline(
28        stt=DeepgramSTT(model="nova-2", language="en"),
29        llm=OpenAILLM(model="gpt-4o"),
30        tts=ElevenLabsTTS(model="eleven_flash_v2_5"),
31        vad=SileroVAD(threshold=0.35),
32        turn_detector=TurnDetector(threshold=0.8)
33    )
34
35    session = AgentSession(
36        agent=agent,
37        pipeline=pipeline,
38        conversation_flow=conversation_flow
39    )
40
41    try:
42        await context.connect()
43        await session.start()
44        # Keep the session running until manually terminated
45        await asyncio.Event().wait()
46    finally:
47        # Clean up resources when done
48        await session.close()
49        await context.shutdown()
50
51def make_context() -> JobContext:
52    room_options = RoomOptions(
53    #  room_id="YOUR_MEETING_ID",  # Set to join a pre-created room; omit to auto-create
54        name="VideoSDK Cascaded Agent",
55        playground=True
56    )
57
58    return JobContext(room_options=room_options)
59
60if __name__ == "__main__":
61    job = WorkerJob(entrypoint=start_session, jobctx=make_context)
62    job.start()
63

1curl -X POST "https://api.videosdk.live/v2/rooms" \
2  -H "Authorization: YOUR_VIDEOSDK_API_KEY"
3

1agent_instructions = "You are a professional and friendly AI Voice Call Assistant. Your primary role is to facilitate seamless, natural-sounding voice conversations with users over the phone. You can answer general questions, provide information, assist with scheduling, and guide users through automated processes. Always speak clearly, use polite language, and confirm understanding when necessary. You must never collect sensitive personal information (such as credit card numbers or social security numbers), and you cannot provide legal, medical, or financial advice. If a user requests such information or advice, politely inform them that you are unable to assist and recommend contacting a qualified professional. Always respect user privacy and comply with data protection guidelines. If you are unsure about a request, escalate or suggest speaking with a human representative."
2
3class MyVoiceAgent(Agent):
4    def __init__(self):
5        super().__init__(instructions=agent_instructions)
6    async def on_enter(self): await self.session.say("Hello! How can I help?")
7    async def on_exit(self): await self.session.say("Goodbye!")
8

1pipeline = CascadingPipeline(
2    stt=DeepgramSTT(model="nova-2", language="en"),
3    llm=OpenAILLM(model="gpt-4o"),
4    tts=ElevenLabsTTS(model="eleven_flash_v2_5"),
5    vad=SileroVAD(threshold=0.35),
6    turn_detector=TurnDetector(threshold=0.8)
7)
8

1async def start_session(context: JobContext):
2    agent = MyVoiceAgent()
3    conversation_flow = ConversationFlow(agent)
4    pipeline = CascadingPipeline(
5        stt=DeepgramSTT(model="nova-2", language="en"),
6        llm=OpenAILLM(model="gpt-4o"),
7        tts=ElevenLabsTTS(model="eleven_flash_v2_5"),
8        vad=SileroVAD(threshold=0.35),
9        turn_detector=TurnDetector(threshold=0.8)
10    )
11    session = AgentSession(agent=agent, pipeline=pipeline, conversation_flow=conversation_flow)
12    try:
13        await context.connect()
14        await session.start()
15        await asyncio.Event().wait()
16    finally:
17        await session.close()
18        await context.shutdown()
19
20def make_context() -> JobContext:
21    room_options = RoomOptions(
22        name="VideoSDK Cascaded Agent",
23        playground=True
24    )
25    return JobContext(room_options=room_options)
26
27if __name__ == "__main__":
28    job = WorkerJob(entrypoint=start_session, jobctx=make_context)
29    job.start()
30

1python main.py
2