Core Concepts
These are the essential building blocks of Caller AI. Once you understand these concepts, you will be able to create powerful AI assistants that handle both inbound and outbound phone conversations with natural accuracy.
1. System Prompt and Initial Message
System Prompt
This is the brain of your AI assistant. It is where you define:
- personality
- tone
- objectives
- rules
- what the AI should or should not say
- how it handles questions
- how it qualifies leads
- how it reacts to objections
- how it closes or routes calls
Everything your assistant does starts from this prompt. Your system prompt determines the AI’s behavior in every situation.
"Act as a friendly appointment setter for ABC Company. Confirm the caller’s information, gather their details, answer FAQs, and book appointments when the caller qualifies."
Initial Message
This is the first thing your AI says when the call begins. The initial message sets the tone for the entire call.
"Hi, thanks for calling ABC Company. How can I help you today?"
"Hi, this is Alex with ABC Company. I saw you recently requested information. Is this still a good time to talk?"
2. Voices
Caller AI includes premium natural sounding voices and supports voice cloning. You can:
- choose from a library of AI voices
- clone your own voice
- adjust speed
- adjust clarity
- adjust emotion
- support multiple languages
The voice you choose greatly impacts the caller experience.
3. Putting It All Together
Your AI assistant is formed by combining:
- your system prompt
- your initial message
- your chosen voice
- your selected tools (transfer, end call, text follow up, CRM update, booking, webhooks)
Once the assistant is created:
Inbound calls: Assign the assistant to a phone number so it can answer calls.
Outbound calls: Assign the assistant to a campaign so it can run through your leads.
Caller AI takes care of the call logic, speech recognition, voice output, workflows, and real time actions.
Next Steps
Learn how call minutes and billing work to plan usage, or go to AI Assistants Overview to start creating your first Caller AI assistant.