import type { TokenCounter } from './types.js';
/**
 * Cacheable-prefix analysis.
 *
 * Prompt caching is a byte-for-byte prefix match, so as soon as a template
 * placeholder ({{user}}, ${query}...) is filled with a different value,
 * everything after it stops being cached. The real cacheable prefix of a
 * template is therefore NOT the whole prompt, but whatever precedes the first
 * variable placeholder.
 */
export interface CachePrefixAnalysis {
    /** Total tokens in the prompt. */
    totalTokens: number;
    /** Tokens before the first variable placeholder. With no placeholders, the total. */
    stablePrefixTokens: number;
    /** Text of the first variable placeholder, or `null` when there is none. */
    firstPlaceholder: string | null;
    /**
     * Tokens of NON-placeholder content sitting after the first placeholder:
     * stable instructions that are not cached today and that would be cached if
     * moved ahead of the first placeholder.
     */
    staticTokensAfter: number;
}
export declare function analyzeCachePrefix(prompt: string, count: TokenCounter): CachePrefixAnalysis;
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