# Router

This section will explain in detail the usage of Router. Router has a dedicated configuration node for customization.

```json
"Router": {
  "RouterId": "",
  "Provider": "azure-openai",
  "Model": "gpt-4"
}
```

## How router works

### How to register agent to router?

When you add a new Agent, the Router can automatically read the Agent's configuration, but in order for the Router to distribute the Request to the new Agent, you must set the `AllowRouting` attribute to `True`. For more information on how to use Router, please refer to the Agent/Router chapter.

## Routing capability extension

If you need to expand the capabilities of Router, we only need to add the corresponding **Routing Handler**.

### How to add custom handler?

```csharp
public class TransferToCsrRoutingHandler : IRoutingHandler
{
    public string Name => "order_payment";

    public string Description => "pay the order.";

    private readonly RoutingSettings _settings;

    public TransferToCsrRoutingHandler(RoutingSettings settings) 
    {
        _settings = settings;
    }

    public async Task<RoleDialogModel> Handle(IRoutingService routing, FunctionCallFromLlm inst)
    {
        var result = new RoleDialogModel(AgentRole.User, "I'm connecting the payment gateway, wait a moment please.")
        {
            CurrentAgentId = _settings.RouterId,
            FunctionName = inst.Function
        };
        return result;
    }
}
```

## Routing - Redirection

Router will maintain an Agent call stack and automatically set the currently active Agent based on the conversation status and redirection configuration.

![calling stack](./assets/routing-calling-stack.png)

You can configure redirection rules based on your business needs.

```json
{
    "routingRules": [
        {
            "field": "order_number",
            "required": true,
            "description": "pizza order number",
            "redirectTo": "c2b57a74-ae4e-4c81-b3ad-9ac5bff982bd"
        }
    ]
}
```