/**
 * OpenKernel — Coder rotation engine
 *
 * Turns a dispatch request into an *ordered chain* of concrete backend configs.
 * The four strategies are not alternatives you pick between — they compose:
 *
 *   1. task-type routing / policy tier  → choose WHICH profiles and their order
 *   2. round-robin                      → choose WHERE in that set to start
 *   3. fallback                         → the returned order IS the retry chain
 *
 * The caller runs the head; if it fails, it walks to the next entry. Because an
 * uninstalled backend simply reports "not available" (a failure), availability
 * filtering falls out of fallback for free — no need to know remote state here.
 */
import type { BackendId } from './types.js';
import type { CoderConfig, CoderPolicy, RotationStrategy } from './profiles.js';
/** What the orchestrator asks for. All fields optional — defaults come from config. */
export interface SelectRequest {
    /** Force a strategy; otherwise config.strategy (default 'auto'). */
    strategy?: RotationStrategy;
    /** Pin an explicit profile by name (still yields config fallbacks behind it). */
    profile?: string;
    /** Pin an explicit backend (legacy path — no rotation, exact behaviour as before). */
    backend?: BackendId;
    /** Model override applied to the chain head. */
    model?: string;
    /** Task-type key for routing (e.g. 'refactor', 'docs'). */
    taskType?: string;
    /** Policy tier for ordering when strategy is policy/auto. */
    policy?: CoderPolicy;
}
/** A concrete, directly-runnable backend selection. */
export interface ResolvedBackend {
    backend: BackendId;
    model?: string;
    args?: string[];
    env?: Record<string, string>;
    profileName?: string;
}
/** Per-node round-robin cursor, keyed by candidate-set signature. */
export declare class RotationState {
    private cursors;
    /** Advance and return the starting offset for a candidate set of length `len`. */
    next(key: string, len: number): number;
}
/**
 * Build the ordered backend chain for a request. The head is what to run; the
 * remainder is the fallback order. Always returns at least one entry (falls back
 * to the config default profile, then any profile, then a bare 'claude').
 */
export declare function selectChain(cfg: CoderConfig, req: SelectRequest, state: RotationState): ResolvedBackend[];