/**
 * AnthropicCacheStrategy — translates agnostic CacheMarker[] to
 * Anthropic API's `cache_control: { type: 'ephemeral' }` markers.
 *
 * Anthropic-specific behaviors honored:
 *   - **4-marker limit**: Anthropic allows ≤4 cache breakpoints per
 *     request. Strategy clamps oversize candidate sets, keeping the
 *     first 4 in slot order.
 *   - **TTL mapping**: 'short' → default 5min ephemeral; 'long' →
 *     `ttl: '1h'` (1-hour beta).
 *   - **Provider-side hashing**: this strategy doesn't hash — Anthropic
 *     keys cache by exact byte prefix server-side. We don't need
 *     content hashes for the v2.6 surface; reserved for v2.7+ if a
 *     pre-flight cache-warm-check API ships.
 *
 * What this strategy DOES vs DOESN'T do:
 *   - DOES: clamp markers, attach to LLMRequest.cacheMarkers,
 *     extract metrics from response.usage
 *   - DOES NOT: rewrite the wire body. The provider
 *     (BrowserAnthropicProvider) reads `cacheMarkers` and applies
 *     `cache_control` blocks during body construction. Separation of
 *     concerns: strategy decides WHAT to cache; provider knows HOW
 *     to encode on its specific wire.
 *
 * Auto-registers in the strategy registry on module import for
 * provider names: 'anthropic', 'browser-anthropic'.
 */
import type { CacheCapabilities, CacheMarker, CacheMetrics, CacheStrategy, CacheStrategyContext } from '../types.js';
import type { LLMRequest } from '../../adapters/types.js';
export declare class AnthropicCacheStrategy implements CacheStrategy {
    readonly providerName = "anthropic";
    readonly capabilities: CacheCapabilities;
    prepareRequest(req: LLMRequest, candidates: readonly CacheMarker[], ctx: CacheStrategyContext): Promise<{
        readonly request: LLMRequest;
        readonly markersApplied: readonly CacheMarker[];
    }>;
    extractMetrics(usage: unknown): CacheMetrics | undefined;
}