/**
 * Anthropic accepts at most 4 `cache_control` breakpoints per request, counted
 * globally across `tools` + `system` + message content. A rich system prompt
 * (skills + mode + mode-skill hint + plan + autonomy contributors + the two
 * per-turn volatile blocks) can carry 5–7 ephemeral markers, which the API
 * rejects with `400 invalid_request`. This is the single chokepoint that caps
 * the count, keeping the markers that protect the most cache and dropping the
 * redundant middle ones.
 *
 * Dropping a middle breakpoint never worsens caching: Anthropic matches the
 * longest cached prefix, and a dropped shorter prefix is fully contained in the
 * next kept (longer) prefix — it was only a redundant fallback. The function
 * never *adds* a marker, so it can only ever preserve or improve validity.
 */
export declare const ANTHROPIC_MAX_BREAKPOINTS = 4;
interface WireBody {
    tools?: unknown;
    system?: unknown;
    messages?: unknown;
}
/**
 * Ensure at most `limit` cache_control breakpoints reach the wire. When over
 * budget, keep: the first marker (anchors the fully-static tools+identity
 * prefix), the last marker (largest incremental prefix — the conversation
 * cache-hit each turn), every pinned/ttl marker (honors caller intent), the
 * second-newest marker inside `messages`, then fill remaining slots by the
 * largest prefix-token gap so the surviving breakpoints partition the request
 * as evenly as possible. `cache_control` is deleted from every dropped block in
 * place — so the wire objects must be fresh clones, never shared with
 * `ctx.systemPrompt`.
 *
 * The two newest message markers are kept together on purpose: they are this
 * request's prefix and the entry the PREVIOUS request wrote. Keeping only the
 * deepest one leaves the hit to Anthropic's bounded automatic look-back, which
 * a turn with many parallel tool calls can overrun. Gap-fill would rank the
 * pair poorly — they sit close together at the very end — so it is selected
 * before the generic fill.
 */
export declare function capAnthropicCacheBreakpoints(body: WireBody, limit?: number): void;
export {};
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