/**
 * SpeechProviderRegistry — central lookup for SpeechProviderPlugin instances.
 *
 * Per docs/voice-rearchitecture.md §11:
 *   - Bundled providers (openai/alibaba/edge/minimax/local-cli) self-register at
 *     module load time via `registerSpeechProvider()`.
 *   - Extension-loaded providers register through `extensions/sdk/speech.ts`
 *     re-exports of the same registration call.
 *   - Lookup is case-insensitive on `id` and `aliases`.
 *   - Re-registering the same id LOGS a warning and OVERWRITES (later registration
 *     wins — used by user extensions to override bundled defaults).
 *
 * DECISION: We do NOT separate "loaded vs configured" the way openclaw does
 * (their `listLoadedSpeechProviders` vs `listSpeechProviders`). xopc's extension
 * model is much simpler — extensions either load successfully or they don't.
 * If a provider is in the registry, it's loaded; whether it's configured is a
 * runtime question answered by `provider.isConfigured(ctx)`.
 */
import type { SpeechProviderId, SpeechProviderPlugin } from './speech-provider-types.js';
/**
 * Register a speech provider. Safe to call multiple times during boot — later
 * registrations overwrite earlier ones for the same id (with a warn log).
 *
 * Returns an unregister function for tests / hot-reload scenarios.
 */
export declare function registerSpeechProvider(provider: SpeechProviderPlugin): () => void;
/**
 * Look up a provider by id or alias (case-insensitive). Returns undefined when
 * no provider matches — callers must NOT throw here; the orchestrator decides
 * whether the absence is fatal or means "skip and try next provider".
 */
export declare function getSpeechProvider(id: SpeechProviderId): SpeechProviderPlugin | undefined;
/**
 * Resolve the canonical id for a provider lookup key (id or alias).
 * Useful for normalizing config strings before persistence.
 */
export declare function canonicalizeSpeechProviderId(id: SpeechProviderId): SpeechProviderId | undefined;
/**
 * List all registered providers. Order is registration order (Map preserves
 * insertion order, and we de-dup by id at registration time).
 */
export declare function listSpeechProviders(): SpeechProviderPlugin[];
/** Test-only: clear the registry. Not exported from the public barrel. */
export declare function _clearSpeechRegistryForTests(): void;