/**
 * OpenAI Chat Completions surface. This is the gateway's "core" dialect: it is
 * what OpenAI-compatible providers speak, what opencode and the Cursor IDE
 * consume directly, and what the Anthropic and Responses adapters translate
 * down to. The handlers here are deliberately thin — the request is forwarded
 * to the backend and the upstream response (including SSE streams) is piped
 * straight back — so the only logic is filling in a default model.
 */
/** Fill in `model` from the backend default when the caller omitted it. */
export declare function withDefaultModel(body: unknown, defaultModel: string | undefined): unknown;
/** Whether a chat/completions request asked for a streamed response. */
export declare function isStream(body: unknown): boolean;
/** The model id a request will run as, after default injection. */
export declare function effectiveModel(body: unknown, defaultModel: string | undefined): string | undefined;