> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vaanivoice.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Build from Scratch
> Start with a blank canvas to design custom, multi-branch conversational workflows and strict compliance rules
Building from scratch provides complete control over every parameter of your voice agent. This approach is designed for teams with existing prompt engineering specifications, intricate conditional logic, strict regulatory compliance requirements, or bespoke multi-step API integrations.
## When to Build from Scratch
* **Multi-Branch Dialog Flows**: Workflows requiring strict step-by-step state machines (e.g., identity verification before payment processing).
* **Compliance & Legal Disclaimers**: Exact mandatory phrases that must be spoken verbatim before continuing the call.
* **Complex API Orchestration**: Calls where the agent triggers multiple custom tools or database operations mid-conversation.
* **Custom Dynamic Variables**: Advanced prompts requiring several dynamic caller attributes injected at runtime.
***
## Step-by-Step Walkthrough
Click **+ New Agent** in the Vaani dashboard and select **Build from Scratch**.
Assign an internal slug or identifier (e.g. `loan-kyc-agent-v2`). This name is only visible to your internal team.
In the prompt editor, compose your agent's instructions using structured markdown sections:
```markdown theme={null}
### 1. IDENTITY & GOAL
You are Maya, an account specialist at FinCorp. Your objective is to verify customer details and schedule loan verification visits.
### 2. CONVERSATIONAL RULES
- Always verify the caller's identity by asking for the last 4 digits of their SSN/Aadhaar.
- If the user interrupts, stop speaking immediately and address their statement.
- Never guess interest rates; always refer to the rate chart in the knowledge base.
### 3. CONVERSATION PHASES
- Phase 1: Greeting & Identity Verification
- Phase 2: Loan Purpose & Desired Amount
- Phase 3: Appointment Booking via Tool
- Phase 4: Confirmation & Warm Farewell
```
Specify dynamic runtime placeholders in curly braces `{}`:
```json theme={null}
{
"customer_name": "string (required)",
"application_id": "string (required)",
"outstanding_balance": "number (optional)"
}
```
These variables are populated automatically when you initiate a call via the API or campaign dialer.
Manually select providers for each stage of the voice loop:
* **Ears (STT)**: Deepgram Nova-2 with customized vocabulary boosting.
* **Brain (LLM)**: Model choice (e.g., Claude 3.5 Sonnet or GPT-4o) and temperature settings (`0.2` for strict compliance, `0.7` for open conversation).
* **Mouth (TTS)**: Voice engine, accent, speaking speed, and pitch.
Draft the greeting message and choose whether the agent speaks first or listens for the caller's initial greeting.
Click **Save Agent**. Your agent is stored, and a UUID `agent_id` is created for production use.
***
## Best Practices for Scratch Building
Phone conversations feel natural when sentences are short (1-2 sentences per turn). Avoid long monologue blocks.
Explicitly instruct the agent on what to do when background noise is high or the caller's answer is ambiguous.
Instruct the model to pronounce numbers phonetically when reading back OTPs, card numbers, or dates.
Use the in-browser simulator to test interruptions, non-sequiturs, and rapid topic switching.
***
## Next Steps
Review your newly configured agent's dashboard
Equip your agent with custom API tools and training documents
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