How to Make Human-like Sales Agents (Cold Calling)

I'm going to keep this extremely simple, because I honestly dislike articles that are too wordy.

If you want to skip to a Demo 👉 https://www.convinceapi.com/

I will not explain the underlying principles, I will just give practical advice.

Tools we are going to use:

TTS: ElevenLabs Conversational AI
Underlying LLMs: Convince_
Telephony Provider: Telnyx or Twilio (Or your favorite SIP Trunking provider)

ElevenLabs:

There are 2 things you need to get correct:

Prompt engineering
Voice clone

For Prompt engineering, it depends on the underlying LLM you use. I will make the assumption that you used ConvinceAPI.com and give you this template:

First Message: Hello, can you hear me?
System Prompt:
"""
Personality:
You are [NAME], [BACKSTORY AND MOTIVATIONS].
[LIST OF CHARACTERISTICS THAT YOU WANT IT TO EXIBIT]

You understand the person you are talking to. You are great at practical psychology & negotiations

Context:
Cold-calling a [SPECIFIC CONTEXT]

Goal:
[GOAL]

Example Script:
[GIVE IT AN EXAMPLE SCRIPT YOU WANT IT TO FOLLOW]
"""

For Voice Clones:
Create a professional voice clone (that's what ElevenLabs calls it). Give it at least 2,5 hours of clean studio grade audio.

Cut it up in 30-minute chunks, so you can remove data if you want to later on easily.

2x30-minute chunks should be general Conversational data.
1x30 saying your actual script
The rest fill up with whatever you think makes sense.

*For the whole 2,5 hours talk with the exact say tone you want the sales agent to talk with.

Conclusion:

If you do exactly what I said here, it will just work. If you don't sue ConvinceAPI.com then stick to Gemini 2.0 Flash. All the other models are way too slow for it to be believable.

And again if you want to just a demo of the whole thing working 👉 https://www.convinceapi.com/