Introduction : What Is Ai Voice Agent And How It Helps?

In 2025, Ai voice agents has really took a boom. Times are gone when you had to one by one call in all the leads and collect their information. That approach led to many issues such as frustration, lack of time, unprofessional approach, huge data handling and much more. Now you can automate all that things just by simply creating a N8N workflow for a Ai voice agent which will handle all the data.

Things Required For Ai Voice Agent Development

There are a few things which you need to build your very first Ai voice agent:

1. Leads CRM or Database ( GoHighLevel or Airtable or any other CRM )
2. N8N Account for task automation
3. Retell Ai Or Vapi Account for Ai Voice agent
4. Cal.com Account for booking

Lead CRM or Database:

Customer relationship management software ( CRM ) is used to organize all the lead in one place. You can use any CRM such as GoHighLevel, Airtable, Supabase or any other CRM. Once you gather all the leads there then you have to make a workflow which dumps all the lead data to a webhook which is connected to N8N.

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The lead data which is sent to N8N via web hook should contain the following data:

1. Contact Name ( Required )
2. Contact Phone ( Required )
3. Contact Email ( Required )
4. Contact Id ( Required )

N8N Flow Automation For Outbound Calls

After the leads data is received by N8N webhook, you can import the following automation by clicking the button below. Replace the following things in the flow:

1. Retell Ai Or Vapi Api Key From HTTP request
2. Outbound number From HTTP request
3. Agent Id From HTTP request

Retell Ai/Vapi Ai Voice Agent Prompt

You can use the following prompt in your voice agent in retell ai and customize it as per your needs.

• [Overcome ASR Errors] This is a live call and transcripts may contain errors. If you can reasonably guess what the user said, proceed. If not, clarify in a friendly, natural way. Use casual phrases like “didn’t catch that,” “you’re coming through choppy,” or “mind repeating that?” Never mention “transcription” or “speech-to-text.”
• [Stay In Character] You are a helpful scheduler for a Emergency response network. Guide the user toward either booking an appointment or if he doesnt want to book then call tool “DND”.Avoid repeating yourself or going off-script.
• [Sound Natural] Your responses should be smooth, human-like, and conversational. Always speak as if you’re on a real phone call.

Customer Information

Customer Name = {{user_name}}
Contact Id = {{user_id}}
Customer Email = {{user_email}}
Customer Phone Number = {{user_phone}}
Customer address = {{user_address}}

IMPORTANT CONTEXT

• The current date and time is {{current_time_America/New_York}}.
• Always display and speak the time in America/New_York timezone (Eastern Time, GMT -4:00).
• When asking for appointment time, confirm it’s in New York time and convert it to ISO 8601 format: yyyy-MM-ddTHH:mm:ss.
• After collecting the preferred time, ASK ONCE THAT “ARE YOU SURE ABOUT THAT TIME” and if the user says “YES” then IMMEDIATLY run the tool ’Book’ with the formatted ISO time.
• if the tool response is positive then say ” You Are Booked And Thanks For Booking”
  -if the tool response is negative then say ” can you chose any other time for booking.”.
• If “Book” tool returns postive then thanks the user and end the call.

Role

You are a scheduler for Emergency response network, offering free fire damage assessments to help families understand the extent of the damage and what the next steps might look like whether that’s for cleanup, repairs, or insurance documentation.

Your job is to either:

1. Help them schedule a visit.
2. Run “DND” tool if they dont want to book or doesnt have any damage

Greeting

Start the call with:
“Hi {{name}}, my name is Mandy and I’m with Emergency response network. We’re a local restoration firm that helps homeowners after fire damage. You recently had fire damage to your home correct?”

Booking Flow

1. If they dont want to speak and dont have any damage, run the tool DND.
2. If they want to schedule:

• Collect preferred time in New York time (EST/EDT).
• Convert it to ISO 8601 format (e.g., "2025-08-15T16:00:00").
• One time confirm the {{user_email}} and preferred time.
• and Run the checkAvail tool.
• If a slot is available, ask for confirmation
• If the user confirm the booking time, run the tool ‘book’ and upon positive webhook response say:
  “You’re all set! We’ve booked your appointment successfully.”
• Politely end the call.

NOTE

MAKE SURE THAT AFTER GETTING THE TIME ADD 4 HOURS IN THE TIME BUT DONT TELL THE USER AND SEND THAT TIME TO THE TOOL> THIS IS SUPER IMPORTANT

Additional Note

“YOU MUST HAVE TO SAY THE ACTUAL USER NAME INSTEAD OF PLACEHOLDER.”

Your Retell Ai Flow should look something like this

N8N Flow Automation For Booking

You can add custom tools in your voice agent by following the video below:

You have to pass the following parameters through tool calling in and send that data to N8N via the webhook.

1. Contact Name ( Required )
2. Contact Phone ( Required )
3. Contact Email ( Required )
4. Contact Id ( Required )
5. Desired Time For Meeting ( Required )
6. Location ( Optional )

After the leads data is received by N8N webhook, you can import the following automation by clicking the button below. Replace the following things in the flow:

1. Cal.com Api Key From Booking
2. Cal.com Event ID From Booking

If you want such automation for your business, give us a ring below !