BaseLLMProvider

Defined in: src/providers/base/BaseLLMProvider.ts:75

Abstract base class for LLM providers in CompositeVoice.

Remarks

BaseLLMProvider extends BaseProvider and implements the LLMProvider interface. It provides shared helpers for building message arrays and merging generation options, while requiring subclasses to implement the primary handler method processMessages.

The handler/guard pattern:

1. Handler methods (processMessages, processText) receive data and produce results as async iterables of text chunks.
2. Guard methods (isToolCall) allow the orchestrator to interpret response chunks without coupling to provider-specific logic.

All LLM providers communicate over REST (type = 'rest') and follow a Receive Text -> Send Text contract:

• Input: a plain-text prompt or an array of LLMMessage objects.
• Output: an AsyncIterable<string> that yields text chunks (supports both streaming and non-streaming implementations).

Inheritance hierarchy:

BaseProvider
 +-- BaseLLMProvider          <-- you are here
      +-- AnthropicLLM        (streaming SSE)
      +-- OpenAILLM           (non-streaming / streaming)
      +-- GroqLLM             (streaming)
      +-- WebLLMLLM           (in-browser inference)

Example

import { BaseLLMProvider } from 'composite-voice';
import type { LLMProviderConfig, LLMGenerationOptions, LLMMessage } from 'composite-voice';

class MyLLMProvider extends BaseLLMProvider {
  constructor(config: LLMProviderConfig) {
    super(config);
  }

  protected async onInitialize(): Promise<void> { }
  protected async onDispose(): Promise<void> { }

  async *processMessages(messages: LLMMessage[], options?: LLMGenerationOptions) {
    const merged = this.mergeOptions(options);
    const response = await myApi.chat(messages, merged);
    yield response.text;
  }
}

See

• BaseProvider for the root provider lifecycle
• LLMProvider for the interface contract

Extends

• BaseProviderClass

Extended by

• OpenAICompatibleLLM
• AnthropicLLM
• WebLLMLLM

Implements

• LLMProvider

Constructors

Constructor

new BaseLLMProvider(config, logger?): BaseLLMProvider;

Defined in: src/providers/base/BaseLLMProvider.ts:89

Create a new LLM provider.

Parameters

Returns

BaseLLMProvider

Overrides

BaseProviderClass.constructor

Properties

Accessors

isProxyMode

Get Signature

get protected isProxyMode(): boolean;

Defined in: src/providers/base/BaseProvider.ts:286

Whether the provider is in proxy mode.

Returns

boolean

true when proxyUrl is set.

Inherited from

BaseProviderClass.isProxyMode

Methods

assertAuth()

protected assertAuth(): void;

Defined in: src/providers/base/BaseProvider.ts:272

Validate that auth is configured (either apiKey or proxyUrl).

Returns

void

Remarks

Call this in onInitialize() for any provider that requires external authentication. Native providers (NativeSTT, NativeTTS) and in-browser providers (WebLLM) should NOT call this method.

Throws

ProviderInitializationError Thrown when neither apiKey nor proxyUrl is set.

Inherited from

BaseProviderClass.assertAuth

assertReady()

protected assertReady(): void;

Defined in: src/providers/base/BaseProvider.ts:255

Guard that throws if the provider has not been initialized.

Returns

void

Remarks

Call at the start of any method that requires the provider to be ready.

Throws

Error Thrown with a descriptive message when initialized is false.

Inherited from

BaseProviderClass.assertReady

dispose()

dispose(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:154

Clean up resources and dispose of the provider.

Returns

Promise<void>

Remarks

Delegates to the subclass hook onDispose and resets the initialized flag. If the provider is not initialized, the call is a no-op.

Throws

Re-throws any error raised by onDispose.

Implementation of

LLMProvider.dispose

Inherited from

BaseProviderClass.dispose

generate()

abstract generate(prompt, options?): Promise<AsyncIterable<string, any, any>>;

Defined in: src/providers/base/BaseLLMProvider.ts:130

Generate a response from a single user prompt.

Parameters

Returns

Promise<AsyncIterable<string, any, any>>

An async iterable of text chunks.

Remarks

Required by the LLMProvider interface. Subclasses must implement this.

Implementation of

LLMProvider.generate

generateFromMessages()

abstract generateFromMessages(messages, options?): Promise<AsyncIterable<string, any, any>>;

Defined in: src/providers/base/BaseLLMProvider.ts:144

Generate a response from a multi-turn conversation.

Parameters

Returns

Promise<AsyncIterable<string, any, any>>

An async iterable of text chunks.

Remarks

Required by the LLMProvider interface. Subclasses must implement this.

Implementation of

LLMProvider.generateFromMessages

getConfig()

getConfig(): LLMProviderConfig;

Defined in: src/providers/base/BaseLLMProvider.ts:247

Get a shallow copy of the current LLM configuration.

Returns

LLMProviderConfig

A new LLMProviderConfig object.

Overrides

BaseProviderClass.getConfig

initialize()

initialize(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:127

Initialize the provider, making it ready for use.

Returns

Promise<void>

Remarks

Calls the subclass hook onInitialize. If the provider has already been initialized the call is a no-op.

Throws

ProviderInitializationError Thrown when onInitialize rejects. The original error is wrapped with the provider class name for diagnostics.

Implementation of

LLMProvider.initialize

Inherited from

BaseProviderClass.initialize

isReady()

isReady(): boolean;

Defined in: src/providers/base/BaseProvider.ts:178

Check whether the provider has been initialized and is ready.

Returns

boolean

true when initialize has completed successfully and dispose has not yet been called.

Implementation of

LLMProvider.isReady

Inherited from

BaseProviderClass.isReady

isToolCall()

isToolCall(_chunk): boolean;

Defined in: src/providers/base/BaseLLMProvider.ts:179

Check whether a response chunk represents a tool call.

Parameters

Returns

boolean

true when the chunk represents a tool call.

Remarks

The default implementation returns false. Tool-aware providers override this to detect tool invocations in the response stream.

mergeOptions()

protected mergeOptions(options?): LLMGenerationOptions;

Defined in: src/providers/base/BaseLLMProvider.ts:224

Merge per-call generation options with the provider’s config defaults.

Parameters

Returns

LLMGenerationOptions

A merged LLMGenerationOptions object.

Remarks

Values supplied in options take precedence over values in config. Only defined values are included in the result, allowing providers to distinguish “not set” from explicit values.

onConfigUpdate()

protected onConfigUpdate(_config): void;

Defined in: src/providers/base/BaseProvider.ts:242

Hook called after updateConfig merges new values.

Parameters

Returns

void

Remarks

The default implementation is a no-op. Override in subclasses to react to runtime configuration changes (e.g. reconnect with a new API key).

Inherited from

BaseProviderClass.onConfigUpdate

onDispose()

abstract protected onDispose(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:229

Provider-specific disposal logic.

Returns

Promise<void>

Remarks

Subclasses must implement this method to release any resources acquired during onInitialize (e.g. close connections, free memory).

Inherited from

BaseProviderClass.onDispose

onInitialize()

abstract protected onInitialize(): Promise<void>;

Defined in: src/providers/base/BaseProvider.ts:217

Provider-specific initialization logic.

Returns

Promise<void>

Remarks

Subclasses must implement this method to perform any setup required before the provider can be used (e.g. validate credentials, open connections, load models).

Inherited from

BaseProviderClass.onInitialize

processMessages()

abstract processMessages(messages, options?): Promise<AsyncIterable<string, any, any>>;

Defined in: src/providers/base/BaseLLMProvider.ts:113

Process a conversation and generate a response.

Parameters

Returns

Promise<AsyncIterable<string, any, any>>

An AsyncIterable that yields text chunks as they arrive.

Remarks

Interface: Receive Text -> Send Text. The primary handler method. Returns an AsyncIterable that yields text chunks. When streaming is enabled, multiple chunks are yielded as tokens arrive. When streaming is disabled, a single chunk containing the full response is yielded.

processText()

processText(prompt, options?): Promise<AsyncIterable<string, any, any>>;

Defined in: src/providers/base/BaseLLMProvider.ts:160

Process a single text prompt (convenience wrapper).

Parameters

Returns

Promise<AsyncIterable<string, any, any>>

An AsyncIterable that yields text chunks as they arrive.

Remarks

Converts the prompt to a messages array (optionally prepending a system message from config) and delegates to processMessages.

promptToMessages()

protected promptToMessages(prompt): LLMMessage[];

Defined in: src/providers/base/BaseLLMProvider.ts:195

Convert a plain-text prompt into an LLMMessage array.

Parameters

Returns

LLMMessage[]

A messages array suitable for processMessages.

Remarks

If the provider’s config includes a systemPrompt, it is prepended as a system message. The prompt itself becomes a user message.

resolveApiKey()

protected resolveApiKey(): string;

Defined in: src/providers/base/BaseProvider.ts:325

Resolve the API key for this provider.

Returns

string

The configured API key, or 'proxy' in proxy mode.

Remarks

Returns 'proxy' in proxy mode so that SDK clients (which require a non-empty API key string) can be instantiated without the real key.

Inherited from

BaseProviderClass.resolveApiKey

resolveAuthHeader()

protected resolveAuthHeader(defaultAuthType?): string | undefined;

Defined in: src/providers/base/BaseProvider.ts:366

Resolve Authorization header value for the configured auth type.

Parameters

Returns

string | undefined

The Authorization header value, or undefined in proxy mode.

Remarks

Returns the header value for REST or server-side WebSocket connections:

• 'token' → 'Token <apiKey>'
• 'bearer' → 'Bearer <apiKey>'

Returns undefined in proxy mode.

Inherited from

BaseProviderClass.resolveAuthHeader

resolveBaseUrl()

protected resolveBaseUrl(defaultUrl?): string | undefined;

Defined in: src/providers/base/BaseProvider.ts:307

Resolve the base URL for this provider.

Parameters

Returns

string | undefined

The resolved URL, or undefined when all sources are unset.

Remarks

Priority: proxyUrl > endpoint > defaultUrl.

For WebSocket providers (this.type === 'websocket'), the proxy URL’s http(s) scheme is automatically converted to ws(s).

When no URL is configured and defaultUrl is undefined, the return value is undefined — this lets SDK-based providers (Anthropic, OpenAI) fall back to their own built-in defaults.

Inherited from

BaseProviderClass.resolveBaseUrl

resolveWsProtocols()

protected resolveWsProtocols(defaultAuthType?): string[] | undefined;

Defined in: src/providers/base/BaseProvider.ts:343

Resolve WebSocket subprotocol for authentication.

Parameters

Returns

string[] | undefined

Subprotocol array for new WebSocket(url, protocols), or undefined.

Remarks

Returns the subprotocol array for direct mode based on authType:

• 'token' → ['token', apiKey] (Deepgram default)
• 'bearer' → ['bearer', apiKey] (OAuth/Bearer tokens)

Returns undefined in proxy mode (no client-side auth needed).

Inherited from

BaseProviderClass.resolveWsProtocols

updateConfig()

updateConfig(config): void;

Defined in: src/providers/base/BaseProvider.ts:201

Merge partial configuration updates into the current config.

Parameters

Returns

void

Remarks

After merging, the subclass hook onConfigUpdate is called so providers can react to changed values at runtime.

Inherited from

BaseProviderClass.updateConfig