> ## Documentation Index
> Fetch the complete documentation index at: https://docs.assist.fm/llms.txt
> Use this file to discover all available pages before exploring further.

# Flow builder

> Design visual call flows with drag-and-drop routing logic.

## What is the flow builder?

The flow builder is a visual editor that lets you design how your agent handles different scenarios during a call. Instead of writing complex instructions, you can create a flowchart with nodes that define actions like transferring to a human, playing a message, or branching based on conditions.

## Node types

| Node | Purpose |
| - | - |
| **Start** | The entry point of every flow |
| **Transfer** | Forward the call to a phone number |
| **Message** | Speak a specific message to the caller |
| **Condition** | Branch the flow based on what the caller said |
| **End** | Hang up the call |

## Building a flow

**1. Open the flow builder**

Navigate to your agent's page and click the **Flow** tab.

**2. Add nodes**

Click on the canvas to add new nodes. Select the node type from the menu.

**3. Connect nodes**

Drag from one node's output to another node's input to create connections.

**4. Configure transfer numbers**

For transfer nodes, enter the phone number and an optional label (e.g. "Manager", "Sales desk").

**5. Save your flow**

Click **Save** to apply the flow. Changes take effect on the next call.

> [!TIP]
>
> The flow builder works alongside your agent's text instructions. Use instructions for general behavior and the flow builder for specific routing scenarios.

## Example: reception with transfer

```mermaid theme={null}
graph TD
    A[Start] --> B{Caller wants human?}
    B -->|Yes| C[Transfer to +31 20 123 4567]
    B -->|No| D[Agent answers question]
    D --> E{Resolved?}
    E -->|Yes| F[End call]
    E -->|No| C
```

## Transfer numbers

Transfer nodes specify the phone number to forward the call to. You can configure:

* **Label** — a descriptive name shown in the flow editor (e.g. "Front desk")
* **Number** — the full international phone number including country code

> [!NOTE]
>
> Transfer numbers must be valid phone numbers with country code (e.g. `+31201234567`). The agent will announce the transfer to the caller before forwarding.

## Fallback number

In addition to flow-based transfers, every agent has a **fallback number** setting. This is used when:

* The agent encounters an error
* The caller explicitly asks for a human and no transfer node is configured
* The flow doesn't cover the current scenario

Configure the fallback number in your agent's general settings.


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