/**
 * Assembling a system prompt to a size, rather than to whatever it happens to add up to.
 *
 * "Why still there's a limit?" — because the tool list was the part that had been measured, and it
 * was not the part that mattered. In a real project the overhead was 4,166 tokens against a
 * 4,096-token window even after the tools were cut from 2.3k to 0.6k: the instructions came to
 * 1.3k, and 720 tokens of framework guidance had been appended automatically because the project
 * happens to be Next.js. Nobody asked for that, and on a small window it is a fifth of everything
 * the model will ever see.
 *
 * A prompt built by concatenating whatever applies has no size — it has a size that emerges. Here
 * the sections are declared with a priority, a budget is given, and what does not fit is dropped
 * from the least important end and reported. On a large window the budget is not reached and
 * nothing is dropped, which is the normal case and must stay untouched.
 */
export interface PromptSection {
    /** Shown when reporting what was dropped. */
    name: string;
    text: string;
    /**
     * Lower goes in first. Identity and the rules that prevent harm are 0; guidance that only
     * improves style is last.
     */
    priority: number;
    /** Never dropped, whatever the budget. */
    essential?: boolean;
    /**
     * Cut to this many characters rather than dropped outright, when it does not fit.
     *
     * For sections where a part is worth more than nothing — a project's first lines say what it is
     * even when the rest will not fit.
     */
    truncateTo?: number;
}
export interface Assembled {
    text: string;
    /** Sections left out entirely. */
    dropped: string[];
    /** Sections included but cut short. */
    truncated: string[];
    tokens: number;
}
/**
 * The sections that fit, in the order they were given.
 *
 * Essential sections go in whatever the cost — a prompt without its identity or its safety rules
 * is worse than a prompt that is too long. Everything else is taken in priority order while there
 * is room, and a section with `truncateTo` is cut rather than lost when only part of it fits.
 */
export declare function assembleWithinBudget(sections: readonly PromptSection[], budgetTokens: number): Assembled;
/** What the user is told when part of the prompt did not fit. */
export declare function budgetNotice(result: Assembled, budgetTokens: number): string;
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