import type { Message, ModelConfig, ProviderRequest, ProviderRequestOptions } from "@arnilo/prism";
/** OpenAI Responses `prompt_cache_key` accepted length cap. */
export declare const OPENAI_PROMPT_CACHE_KEY_MAX_LENGTH = 64;
export declare function promptCacheKey(options: ProviderRequestOptions | undefined): string | undefined;
/**
 * OpenAI Responses only accepts `prompt_cache_retention: "24h"` (extended
 * caching). Default short caching is automatic and implicit, so `"short"` and
 * `"none"` omit the field rather than emitting an invalid literal. `"long"`
 * maps to `"24h"` only when the model declares `cache.longRetention`; unknown
 * models omit the field so Prism never sends unsupported retention values.
 */
export declare function promptCacheRetention(options: ProviderRequestOptions | undefined, model: ModelConfig): "24h" | undefined;
/**
 * GPT-5.6+ explicit-only caching: `prompt_cache_options: { mode: "explicit" }`.
 * Activated when the model declares `cache.explicitBreakpoints` and the host
 * supplies `cache.breakpoints` (or forces `cache.mode: "on"`). The only TTL is
 * `"30m"` (also the default), so no ttl field is ever emitted. Older models and
 * `cache.mode: "off"` keep implicit caching with no options field.
 * @see https://developers.openai.com/api/docs/guides/prompt-caching
 */
export declare function promptCacheOptions(options: ProviderRequestOptions | undefined, model: ModelConfig): {
    mode: "explicit";
} | undefined;
export type OpenAIBreakpointMessage = Omit<Message, "content"> & {
    readonly content: readonly (Message["content"][number] & {
        readonly prompt_cache_breakpoint?: {
            readonly mode: "explicit";
        };
    })[];
};
/**
 * Stamp `prompt_cache_breakpoint: { mode: "explicit" }` on the last content
 * block of caller-selected `cache.breakpoints` anchors (shared selection
 * semantics with `applyCacheControl`). Only runs when `promptCacheOptions`
 * activates explicit mode; `tools` breakpoints are skipped (tool definitions
 * are not markable content blocks in Responses).
 */
export declare function applyPromptCacheBreakpoints(request: ProviderRequest): readonly OpenAIBreakpointMessage[];