/**
 * Context Budget Checker
 *
 * Pre-generation validation that estimates total input token cost
 * and compares against the model's available input space.
 *
 * This runs BEFORE every LLM call to prevent context overflow.
 */
import type { BudgetCheckResult, BudgetCheckParams } from "../types/index.js";
/** Default compaction threshold (80% of available input) */
export declare const DEFAULT_COMPACTION_THRESHOLD = 0.8;
/**
 * Tokens the CONVERSATION HISTORY may occupy, i.e. the model's available input
 * space minus everything that rides alongside it (system prompt, current
 * prompt, tool definitions, file attachments).
 *
 * This is the number the compactor must target. Passing it the undeducted
 * `availableInputTokens` made every stage gate compare history-only tokens
 * against the WHOLE budget, so compaction only engaged once history alone
 * exceeded the entire window — with a large MCP tool set a request could sit
 * far over budget while the compactor reported "nothing to do" and fell through
 * to emergency truncation.
 *
 * Returns 0 when the fixed overhead already exceeds the window; callers must
 * treat that as unrecoverable rather than compacting to an empty history.
 */
export declare function resolveHistoryBudget(result: BudgetCheckResult, compactionThreshold?: number): number;
/**
 * Check whether a request fits within the model's context budget.
 *
 * Estimates total input tokens from: system prompt + tool definitions +
 * conversation history + current prompt + file attachments, and compares
 * against available input space.
 */
export declare function checkContextBudget(params: BudgetCheckParams): BudgetCheckResult;