import type { VertexAnthropicCacheInput, VertexAnthropicCacheOutput, VertexAnthropicMessage } from "../types/index.js";
/** Anthropic allows at most four `cache_control` breakpoints per request. */
export declare const ANTHROPIC_MAX_CACHE_BREAKPOINTS = 4;
/**
 * Annotate a native Vertex+Claude request with prompt-cache breakpoints.
 *
 * Budget allocation (max 4 markers):
 *   1. The stable prefix — the last system block when a system prompt is
 *      present (this single marker caches `tools + system`, since system
 *      renders after tools); otherwise the last tool definition.
 *   2-4. A rolling breakpoint on the last few messages, so the
 *      growing-but-now-stable conversation history is cached and only the
 *      newest turn is billed as fresh input.
 *
 * Pure: the inputs are cloned, never mutated.
 */
export declare function applyVertexAnthropicCacheBreakpoints(input: VertexAnthropicCacheInput): VertexAnthropicCacheOutput;
/**
 * Count the `cache_control` markers already present on a request. The direct
 * Anthropic path (AI-SDK pipeline) arrives with markers the upstream layers
 * placed — MessageBuilder tags the system prompt, GenerationHandler tags the
 * last tool definition, and message content blocks may carry translated
 * AI-SDK markers. Anthropic rejects requests with more than four markers, so
 * any additional history breakpoints must fit in the remaining budget.
 */
export declare function countAnthropicCacheMarkers(input: {
    system?: string | ReadonlyArray<{
        cache_control?: unknown;
    }> | undefined;
    tools?: ReadonlyArray<{
        cache_control?: unknown;
    }> | undefined;
    messages: ReadonlyArray<VertexAnthropicMessage>;
}): number;
/**
 * Rolling history breakpoints for request paths whose stable-prefix markers
 * are managed upstream (direct Anthropic: system via MessageBuilder, last
 * tool via GenerationHandler). Marks the last content block of up to `budget`
 * tail messages; a tail block that already carries a marker is left as-is
 * without consuming budget (it already serves as that breakpoint). Pure —
 * the input array is cloned, never mutated.
 */
export declare function applyAnthropicHistoryCacheBreakpoints(input: ReadonlyArray<VertexAnthropicMessage>, budget: number): VertexAnthropicMessage[];