/**
 * Picks the LLM backend (invariant #5). An explicit `backend` wins; then `CAIRN_LLM_BACKEND`
 * (lets the CLI pick key-less backends like codex/claude-code); otherwise the first provider
 * whose API key is present, in order Anthropic → OpenAI → Gemini, falling back to local Claude Code.
 */
import type { LlmClient } from "../../core/ports.js";
export type LlmBackend = "anthropic" | "openai" | "gemini" | "claude-code" | "codex";
export interface LlmFactoryOptions {
    /** Force a backend regardless of environment. */
    backend?: LlmBackend;
    model?: string;
}
export declare function createLlmClient(opts?: LlmFactoryOptions): LlmClient;