Helpers provide additional ways to interact with your bot pipeline. They offer a common interface for working with transports, events, and messages within the context of a specific service.

Since RTVI does not make any assumptions about which services a developer will leverage in their bots, helpers reduce unnecessary functionality in your voice clients and facilitate framework extensibility.

Some examples of where helpers can be useful include:

  • LLM message context modificiation
  • Direct text-to-speech output
  • Multi-lingual workflows
  • Custom convenience functions

It’s easiest to think of helpers as wrappers around existing voice client functionality that target a specific service, making your RTVI codebase less verbose.

​
Using a helper

Helpers must be imported, defined and registered to you voice client.

Here is an example using the included LLM helper:

import {
  LLMHelper,
  LLMHelperEvent
  VoiceMessage,
} from "realtime-ai";

const voiceClient = new VoiceClient({
    services: {
        llm: "openai"
    },
    config: [ 
        // ...
    ]
});

const llmHelper = new LLMHelper({
    callbacks: {
        onLLMContextUpdate: (messages) => {
            // ...
        }
    }
});

voiceClient.registerHelper("llm", llmHelper);

// Events
voiceClient.on(LLMHelperEvent.LLMContextUpdate, (messages) => console.log(messages));

await llmHelper.appendContext({
    role: "user",
    content: "Tell me a joke!",
 });

​
Registering a helper

Registering a helper provides it with a reference to your voice client. Helpers must be registered in order to use event and action dispatch / resolution.

voiceClient.registerHelper(service, helper);

service
string
required

Service targeted by the helper as part of your voice client constructor services map. An exception is thrown if no matching service can be found.

Note: targeting services is required for scenarios where a pipeline contains multiple declarations of the same service type. For example, your pipeline may have two or more LLM services registered.

helper
VoiceClientHelper
required

A helper subclass instance of VoiceClientHelper.

​
Retrieving a helper

The voice client holds a reference to all registered helpers. This can be useful if you do not want to hold / pass a reference across your codebase:

const llmHelper = voiceClient.getHelper("llm") as LLMHelper;

​
Unregistering a helper

A service in your pipeline can currently have reference to a single helper to avoid conflicting action dispatch.

You can unregister a helper from a service like so:

voiceClient.unregisterHelper("llm")

Unregistering helpers will not delete any references in your own code. Any subsequent attempts to use an unregistered helper against the service name will raise an exception.

If you register a new helper with the same service name and use a previous helper instance, you may encounter errors.

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How are helper messages handled?

The VoiceClientHelper base class requires that a helper define a handleMessage method.

Any RTVI messages received from the transport that does not match native voice client message types are passed through to your client’s registered helpers:

public handleMessage(ev: VoiceMessage): void {
    switch(ev.type) {
        case MyHelperMessageType.SOME_MESSAGE:
            this._options.callbacks.onSomeMessage(ev.data);
            break;
            // etc
    }
}

Be mindful of defining a ‘default’ switch handler if you have multiple registered helpers listening for the same message type. Catching them will prevent lower order helpers from receiving the message.

​
Writing helpers

Creating your own helper classes can be useful when you want to create reusable code that targets a specific service (or series of services.)

The abstract VoiceClientHelper class is intentionally lightweight to provide as much flexibility to the developer as needed.

A typical helper definition will likely include:

  • A constructor
  • Callback methods
  • Event and message types

A basic implementation of a helper would look like this:

ErrorsLLM Helper