/** Provider-neutral transcription contract (plan 061 Task 3).
 *  One-shot audio→text plus a streaming variant yielding partials; both share the
 *  `TranscriptDelta` event type aligned with `RealtimeEvent.transcript_delta` naming.
 *  Adapters enforce audio byte caps with typed errors — they never silently truncate. */
import type { ModelCapabilities, ModelConfig, Usage } from "./content.js";
export interface TranscriptionRequest {
    readonly model: string;
    /** Audio bytes to transcribe. */
    readonly audio: Uint8Array;
    /** Audio container hint, e.g. `wav`, `mp3`; the adapter maps it to an upload filename. */
    readonly format?: string;
    /** ISO-639-1 hint, e.g. `en`. */
    readonly language?: string;
    /** Optional spelling/style hint text. */
    readonly prompt?: string;
    readonly signal?: AbortSignal;
}
export interface TranscriptionResult {
    readonly text: string;
    /** Provider-reported token usage; absent when the provider does not report it. */
    readonly usage?: Usage;
}
/** Partial transcript. Naming mirrors `RealtimeEvent.transcript_delta` (no `role` —
 *  one-shot transcription has no speaker turn). */
export interface TranscriptDelta {
    readonly type: "transcript_delta";
    readonly text: string;
}
/** Terminal event: final full text plus optional usage. Exactly one per stream. */
export interface TranscriptDone {
    readonly type: "done";
    readonly text: string;
    readonly usage?: Usage;
}
export type TranscriptEvent = TranscriptDelta | TranscriptDone;
export interface TranscriptionProvider {
    readonly id: string;
    transcribe(request: TranscriptionRequest): Promise<TranscriptionResult>;
    /** Yields `transcript_delta` partials in order, then exactly one `done`. */
    transcribeStream(request: TranscriptionRequest): AsyncIterable<TranscriptEvent>;
}
export type TranscriptionErrorCode = "empty_input" | "audio_too_large" | "request_failed" | "response_malformed" | "unsupported_model";
export declare class TranscriptionError extends Error {
    readonly code: TranscriptionErrorCode;
    constructor(code: TranscriptionErrorCode, message: string);
}
export declare function modelSupportsTranscription(capabilities?: ModelCapabilities): boolean;
export declare function assertTranscriptionSupported(model: ModelConfig): void;